Dissertations / Theses on the topic 'Dugongs'

In order to define small and large scale spatial and temporal individual movement patterns of dugongs (Dugong dugon) within the Shark Bay World Heritage Property (SBWHP) a total of 19 dugongs were fitted with remote location recording and transmitting devices. Combined locations from all units totalled over 10,000 locations. This spatial and temporal data was used to define movement patterns of dugongs within Shark Bay as well as areas of high use deemed to be indicative of foraging activity. Platform Transmitting Terminals (PTT?s) using the ARGOS location collection system tracked animals over large temporal scales with 4 animals tracked up to periods of 11 months. Using these instruments it was possible accurately define a previously identified large-scale seasonal movement pattern within the confines of Shark Bay. These four animals showed distinct seasonal home ranges defined by changes in Sea Surface Temperature.

Algal toxins can have a significant impact on human and ecological health as the toxins accumulate in the food chain and are consumed by both humans and marine organisms. This study focussed on the following marine algal toxins that were present at the study sites: okadaic acid (OA), domoic acid (DA), gymnodimine (GD), pectenotoxin-e (PTX-2) and PTX-2 seco acid (PTX-2SA). The study sites investigated for potential algal toxin exposure were selected from the waters around North Stradbroke Island, Queensland, Australia, where shellfish are harvested by the local population, and where dugongs are known to feed on seagrass. Samples were collected monthly for two consecutive years. The species of toxinproducing algae present at the sites studied were Pseudo-nizschia sp., Dinophysis caudata, D. acuminata and Prorocentrum lima. The occurrence of Dinophysis species was observed to be dependent on the season while Pseudo-nitzschia sp was present both in colder and warmer months. Data on the dose-response analysis were extracted from published literature. This data was categorised into whole organisms, human and animal cell lines, and compared to one another. For further toxicodynamic studies, human cell lines were dosed with known concentrations of the toxins: OA, DA and GD. These cytotoxicity and microarray analyses were performed to observe the effects of toxins on gene regulation. A more extensive analysis was performed using GD alone. Expression of numerous genes was affected, and real time polymerase chain reaction reactions were performed to confirm the regulation of those genes. Gymnodimine was demonstrated to affect genes within pathways relating to oxidative phosphorylation, apoptosis, MAPK and Wnt signalling pathways. The cytotoxicity and microarray data and the data accumulated from the published literature were combined to form a comprehensive database of both chronic and acute effects. The database was then referred to for the dose-response analysis for the risk assessment. The exposure data attained from field sampling in the current study was analysed against the doses for any shown effects. Total daily intake for humans and dugongs sourcing food from around the island were calculated and health risks were estimated by incorporating tolerable daily intake, guideline values and total daily intake. The risk characteristics of algal toxins on the health of humans (consuming shellfish) and dugongs (consuming seagrass) indicated that acute health risks were unlikely, unless an outbreak of toxic algae (algal bloom) were to occur. Since there were no occurrences of algal blooms during the study period, high levels of toxins were not detected in any of the collected shellfish, phytoplankton or seagrass samples. However, if such blooms were to occur around the island, the phytoplankton could potentially produce algal toxins at high enough concentrations to cause acute toxic effects in the consumers. The current study has also demonstrated that there is a potential for chronic, long term health effects from consuming shellfish and seagrass around the island. The presence of low-level concentrations of algal toxins in the food sources can lead to chronic effects. Toxins such as OA are known tumour promoters. For dugongs, which feed on seagrass on daily basis, the potential for chronic effects is high. It was demonstrated that GD also possesses toxicological characteristics that may enhance the possibility of tumour promotion because of its effect of down-regulating parts of the apoptosis pathway, which may prevent cell death and as a consequence, lead to uncontrolled cell growth.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Faculty of Science, Environment, Engineering and Technology
Full Text

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans(PCDFs) are two groups of lipophilic, persistent organic pollutants that are produced as by-products of various anthropogenic and industrial processes. Due to their relatively high toxic potencies and potential to bioaccumulate and biomagnify in organisms and through the food chain, the contemporary widespread distribution of these compounds is a concern to the health of the environment, wildlife and humans. This study determined the distribution, pathways and fate of PCDD/Fs in the coastal zone of Queensland, Australia, including the inshore marine environment of the World Heritage Great Barrier Reef Marine Park. This ecosystem supports unique fauna and flora such as the marine herbivorous mammal dugong (Dugong dugon) and its food source, seagrass. Elevated PCDD/Fs were present in soils and sediments along the entire Queensland coastline. Highest concentrations were found in soil from agricultural irrigation drains and in sediments near the mouths of major rivers. Elevated concentrations were associated with rural and urban types of land-use, and PCDD/Fs were present even in locations remote from anthropogenic activities. PCDD/F congener-specific analysis revealed an unusual profile in all samples, dominated by OCDD, with PCDFs present in low concentrations or below the limit of detection. Distinct HxCDD isomer patterns were observed, with the 1,2,3,7,8,9-HxCDD/1,2,3,4,6,7-HxCDD isomer pair dominating the 2,3,7,8-substituted HxCDDs. Similar congener and isomer characteristics were reported in sediments, soil and clay samples from other continents, but could not be attributed to any known source. Possible PCDD/F sources in Queensland were assessed using segmented estuarine sediment cores, for which radiochemical chronologies were established for each depth. Variations of PCDD/F concentrations in the sediment cores over several centuries of depositional history were relatively small. Elevated PCDD levels were still present in sediment slices from the early 17th century. PCDD/F homologue profiles in sediments deposited during the last 350 years were almost identical and correlated well to the characteristic profiles observed in surface sediments and soils from the entire Queensland coastline. These results suggested the presence of an unidentified PCDD source prior to the production of commercial organochlorine products. To investigate the formation of the unusual PCDD/F profiles, congener and isomer specific analyses were undertaken in soils, sediments and dated sediment cores. The results demonstrated that specific transformation processes in the environment have resulted in the observed PCDD profile characteristics. Dechlorination of OCDD was proposed to result in distinct 1,4-pattern characteristics (i.e. formation of isomers chlorinated in the 1,4,6,9-positions). Consequently, the environmental samples do not reflect the signatures of the original source. An alternative hypothesis to natural formation is discussed evaluating these processes and their implications for possible source contributions. This hypothesis explores the potential for the influence of anthropogenic PCDD precursors (e.g. pentachlorophenol) during the 1940s to 1990s. Transport of PCDD/Fs from the land-based source via impacted tributary river systems, and subsequent deposition processes are proposed to result in PCDD/F accumulation in the inshore marine ecosystem. The extent of the sediment PCDD/F contamination governs the concentrations in the extensive inshore marine seagrass meadows of Queensland. Partitioning processes in the sediment-seagrass system lead to increased toxic equivalency (TEQ) in the seagrass, compared to sediment.The relationship between contaminated inshore sediments, seagrass and dugongs were evaluated using six dugong habitat regions along the coastline. PCDD/F body burdens in dugongs are governed by sediment (and seagrass) PCDD/F concentrations in their habitat. High seagrass (and incidental sediment) ingestion rates, selective retention of toxicologically potent congeners and relatively low PCDD/F elimination capacities in dugongs are proposed to result in elevated PCDD/F concentrations and TEQ levels in adult animals. Transfer efficiencies of 4 and 27% of maternal TEQ levels to foetuses and calves (respectively) during gestation and lactation result in relatively high exposure potentials to offspring. Compared to no-observed-adverse-effect-levels in other mammals, and based on the results of this study, a tolerable daily intake (TDI) of 10-24 pg TEQ kg-1 day-1 was estimated for dugongs. The results of the present study found that dugongs from some regions along the coastline of Queensland exceed this TDI by up to 20 fold, suggesting that these populations may be at risk from PCDD/F contamination in their habitat. These results have important implications for the health of the environment, wildlife and humans and were used to develop a conceptual understanding of the sources, pathways and fate of dioxins in Queensland, Australia.

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans(PCDFs) are two groups of lipophilic, persistent organic pollutants that are produced as by-products of various anthropogenic and industrial processes. Due to their relatively high toxic potencies and potential to bioaccumulate and biomagnify in organisms and through the food chain, the contemporary widespread distribution of these compounds is a concern to the health of the environment, wildlife and humans. This study determined the distribution, pathways and fate of PCDD/Fs in the coastal zone of Queensland, Australia, including the inshore marine environment of the World Heritage Great Barrier Reef Marine Park. This ecosystem supports unique fauna and flora such as the marine herbivorous mammal dugong (Dugong dugon) and its food source, seagrass. Elevated PCDD/Fs were present in soils and sediments along the entire Queensland coastline. Highest concentrations were found in soil from agricultural irrigation drains and in sediments near the mouths of major rivers. Elevated concentrations were associated with rural and urban types of land-use, and PCDD/Fs were present even in locations remote from anthropogenic activities. PCDD/F congener-specific analysis revealed an unusual profile in all samples, dominated by OCDD, with PCDFs present in low concentrations or below the limit of detection. Distinct HxCDD isomer patterns were observed, with the 1,2,3,7,8,9-HxCDD/1,2,3,4,6,7-HxCDD isomer pair dominating the 2,3,7,8-substituted HxCDDs. Similar congener and isomer characteristics were reported in sediments, soil and clay samples from other continents, but could not be attributed to any known source. Possible PCDD/F sources in Queensland were assessed using segmented estuarine sediment cores, for which radiochemical chronologies were established for each depth. Variations of PCDD/F concentrations in the sediment cores over several centuries of depositional history were relatively small. Elevated PCDD levels were still present in sediment slices from the early 17th century. PCDD/F homologue profiles in sediments deposited during the last 350 years were almost identical and correlated well to the characteristic profiles observed in surface sediments and soils from the entire Queensland coastline. These results suggested the presence of an unidentified PCDD source prior to the production of commercial organochlorine products. To investigate the formation of the unusual PCDD/F profiles, congener and isomer specific analyses were undertaken in soils, sediments and dated sediment cores. The results demonstrated that specific transformation processes in the environment have resulted in the observed PCDD profile characteristics. Dechlorination of OCDD was proposed to result in distinct 1,4-pattern characteristics (i.e. formation of isomers chlorinated in the 1,4,6,9-positions). Consequently, the environmental samples do not reflect the signatures of the original source. An alternative hypothesis to natural formation is discussed evaluating these processes and their implications for possible source contributions. This hypothesis explores the potential for the influence of anthropogenic PCDD precursors (e.g. pentachlorophenol) during the 1940s to 1990s. Transport of PCDD/Fs from the land-based source via impacted tributary river systems, and subsequent deposition processes are proposed to result in PCDD/F accumulation in the inshore marine ecosystem. The extent of the sediment PCDD/F contamination governs the concentrations in the extensive inshore marine seagrass meadows of Queensland. Partitioning processes in the sediment-seagrass system lead to increased toxic equivalency (TEQ) in the seagrass, compared to sediment.The relationship between contaminated inshore sediments, seagrass and dugongs were evaluated using six dugong habitat regions along the coastline. PCDD/F body burdens in dugongs are governed by sediment (and seagrass) PCDD/F concentrations in their habitat. High seagrass (and incidental sediment) ingestion rates, selective retention of toxicologically potent congeners and relatively low PCDD/F elimination capacities in dugongs are proposed to result in elevated PCDD/F concentrations and TEQ levels in adult animals. Transfer efficiencies of 4 and 27% of maternal TEQ levels to foetuses and calves (respectively) during gestation and lactation result in relatively high exposure potentials to offspring. Compared to no-observed-adverse-effect-levels in other mammals, and based on the results of this study, a tolerable daily intake (TDI) of 10-24 pg TEQ kg-1 day-1 was estimated for dugongs. The results of the present study found that dugongs from some regions along the coastline of Queensland exceed this TDI by up to 20 fold, suggesting that these populations may be at risk from PCDD/F contamination in their habitat. These results have important implications for the health of the environment, wildlife and humans and were used to develop a conceptual understanding of the sources, pathways and fate of dioxins in Queensland, Australia.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Public Health
Faculty of Health Sciences
Full Text

Samples of sediment, seagrass and dugong tissues were analyzed for selected elements: Fe, Zn, Cu, Pb, Mn, Cd, Ni, Co, Al, P and S. Iron was the most interesting element found in relation to the samples analyzed. The level of iron in dugong liver tissue is extraordinarily high, ranging from 12 691- 71 123 µg g-1 dry weight. Ferritins from liver of dugong were isolated and characterized. Ferritin was purified by heat treatment and two-column gel filtration on Sephadex G-75 and Sephacryl S-300. Isolation of ferritin was monitored by determining iron to protein ratio. For reference, ferritin was also isolated from human liver and spleen. Purity of the isolated ferritin was determined by analytical electrophoresis. The amino acid composition and subunit nature of the purified ferritin are within the normal range reported for the well-characterized human liver and spleen ferritins and horse spleen ferritin. The core size of purified dugong ferritin was determined by electron microscopy, which also indicated that purified dugong ferritin had a limited crystallinity. Mossbauer spectra of purified ferritin at 78K indicated the presence of ferrihydrite (5Fe2O39H2O) rather than geothite-like (α-FeOOH) iron oxide. This latter iron oxide was detected in the whole liver tissue of dugong. Overall, the characteristics of purified dugong ferritin are similar to other mammalian ferritins. The elemental analysis of dugong tissue, seagrass and sediment in its environment indicated that the dugong studied live in areas of minimum anthropogenic activity. The naturally high level of iron in its environment and food is reflected in the high liver iron values. The ability of the liver tissue to withstand the high concentration of iron in the tissue without apparently damaging the tissue deserves further study.

This thesis explores the relationship between Indigenous knowledge and Australian settler perceptions of medicinal practice by examining the manufacturing and use of dugong oil. It tracks the growth of the dugong industry in Moreton Bay in the mid-nineteenth century, before analysing the way in which dugong oil made its way through the hands of medical practitioners into newspaper advertisements and exhibitions from Australia to Europe. At this time, Australia was following Britain in the move to professionalise medicine despite a continuing popularity of heterodox and home treatments. Discoveries‘ of new medicinal remedies by medical professionals blur the lines of orthodox and unorthodox medicine and add another dimension to this history. Specifically, the case of dugong oil, learned from the Indigenous inhabitants, shows the interconnectedness of the dominant and the minority stories, shedding new light on the history of medicine, products, exchange and ideas in the age of empire.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Humanities, Languages and Social Science
Arts, Education and Law
Full Text

This thesis explores the conflict between conservationists and Indigenous communities over the hunting of marine turtles and dugong in Australia, with a view to finding a way to overcome the barriers that prevent the resolution of this issue. I approached this exploration as an ecologist, using the framework of Berkes (2004) who proposed three shifts for the field of ecology. This meant taking a systems approach and investigating the intertwining threads of the issue as possible, with a specific focus on integrating the human aspects of the problem in a participatory manner. By doing so my work entered into a third space where multiple possibilities for investigation opened up. Through listening to others with expertise on the matter (from both Indigenous and non-Indigenous cultures) I have created a hybrid account of the ecology of marine turtles and dugong in Australia. The methodology used in undertaking this research was reflexive in nature, with a focus upon both my own and Bardi and Jawi culture, utilising interviews and participant observation as my primary methods of data collection. Wherever possible, a collaborative and participatory approach to the research was undertaken, with many people assisting me in my growing understandings of this issue. I have made use of various text-based resources, including the current scientific literature, historical accounts and records and my own field diaries to support the interview data that I collected. This account traces the origins of the conflict over marine turtle and dugong in Australia and focuses on a few key moments where attempts to resolve the issue have occurred over the past twenty years. By viewing these moments through the lens of the ecological discourses described by Manuel-Naverrete et al. (2008), it can be seen that progress towards the resolution of the conflict is unlikely to occur when participants retain a strongly normative worldview, and that movement towards an ecosystemic-pluralistic framework allows for a more flexible and adaptive response to this problem. Furthermore I argue that many of the underlying causes of the conflict are based on non-Indigenous cultures’ painful grappling with our current disassociation from the other-than-human world and that the adoption of a transformative-collaborative approach to our relationship with country may provide an opportunity to heal this rift.

The loss of large-bodied herbivores and/or top predators has been associated with large-scale changes in terrestrial, freshwater, and marine ecosystems around the world. Understanding the consequences of these declines has been hampered by a lack of studies in relatively pristine systems. To fill this gap, I investigated the dynamics of the relatively pristine seagrass ecosystem of Shark Bay, Australia. I began by examining the seagrass species distributions, stoichiometry, and patterns of nutrient limitation across the whole of Shark Bay. Large areas were N-limited, P-limited, or limited by factors other than nutrients. Phosphorus-limitation was centered in areas of restricted water exchange with the ocean. Nutrient content of seagrasses varied seasonally, but the strength of seasonal responses were species-specific. Using a cafeteria-style experiment, I found that fast-growing seagrass species, which had higher nutrient content experienced higher rates of herbivory than slow-growing species that are dominant in the bay but have low nutrient content. Although removal rates correlated well with nutrient content at a broad scale, within fast-growing species removal rates were not closely tied to N or P content. Using a combination of stable isotope analysis and animal borne video, I found that green turtles (Chelonia mydas) – one of the most abundant large-bodied herbivores in Shark Bay – appear to assimilate little energy from seagrasses at the population level. There was, however, evidence of individual specialization in turtle diets with some individuals foraging largely on seagrasses and others feeding primarily on macroalgae and gelatinous macroplankton. Finally, I used exclusion cages, to examine whether predation-sensitive habitat shifts by megagrazers (green turtles, dugongs) transmitted a behavior-mediated trophic cascade (BMTC) between sharks and seagrasses. In general, data were consistent with predictions of a behavior-mediated trophic cascade. Megaherbivore impacts on seagrasses were large only in the microhabitat where megaherbivores congregate to reduce predation risk. My study highlights the importance of large herbivores in structuring seagrass communities and, more generally, suggests that roving top predators likely are important in structuring communities - and possibly ecosystems - through non-consumptive pathways.

Metadon je sintetski agonist opijatnih receptora koji se primenjuje u sklopu supstitucione terapije opijatnih zavisnika metadonom (STM) i u terapiji hroničnog bola. Dugoročna primena STM je praćena blagim, uglavnom prolaznim, neželjenim delovanjima. Međutim, metadon pripada grupi lekova koji mogu da prouzrokuju prolongaciju korigovanog QT intervala (QTc) u elektrokardiogramu (EKG-u) i povećaju rizik za nastanak potencijalno fatalnih aritmija tipa torsades de pointes. Opijatni zavisnici metadon najčešće koriste u kombinaciji sa benzodiazepinima, i ova kombinacija lekova predstavlja faktor rizika za nastanak smrtnog ishoda. Iako je najveći broj lekara upoznat sa rizikom za razvoj respiratorne depresije prilikom primene opijata u kombinacji sa benzodiazepinima, velika studija otkriva da su ventrikularne aritmije i srčani zastoj najčešće prijavljivana neželjena delovanja metadona, primenjenog u kombinaciji sa benzodiazepinima. Ciljevi ovoga radu su da se analizom smrtnih slučajeva povezanih sa upotrebom metadona (MRDs) tokom desetogodišnjeg perioda na teritoriji Vojvodine i sprovođenjem kliničkog ispitivanja kod opijatnih zavisnika na STM proceni kardiološka bezbednost primene metadona, posebno u kombinaciji sa benzodiazepinima. Sprovedena je retrospektivna studija za određivanje karakteristika MRDs na teritoriji Vojvodine, kao i kliničko ispitivanje u kome su učestvovali opijatni zavisnici koji počinju sa STM. Snimanje EKG-a (za izračunavanje QTc intervala) i uzorkovanje krvi (za određivanje koncentracije metadona i diazepama i vrednosti troponina) je sprovedeno kod svih učesnika istraživanja u 5 vremenskih tačaka (pre početka primene STM, 8. i 15. dana i nakon 1. i 6. meseca primene STM). Koncentracije metadona i diazepama u serumu su određivane metodom tečne hromatografije sa masenom spektrometrijom (LC-MS). U Vojvodini je zapažena rastuća tendencija MRDs, ali ni jedan od umrlih nije bio na STM, i najverovatnije su samoinicijativno koristili metadon i benzodiazepine. Patohistološki nalaz na srcu može govoriti u prilog kardiotoksičnosti metadona i njegove kombinacije sa benzodiazepinima, pogotovo kod slučajeva sa pronađenim akutnim miokardijalnim oštećenjem. Što se tiče hroničnih promena na srcu, ne postoji mogućnosti da se potvrdi niti opovrgne uloga psihostimulanasa. Detektovane koncentracije metadona i diazepama kod MRDs su bile u opsegu terapijskih (<1 μg/ml). Poredeći socio-demografske karakteristike opijatnih zavisnika koji su počeli sa STM u ovom istraživanju sa podacima iz sličnih studija sprovedenih širom sveta, zapažena je sličnost u pogledu velikog broja karakteristika. Srednje doze metadona 8., 15. dana i nakon 1. i 6. meseca primene STM su bile 40,23±17,11 mg, 47,11±16,79 mg, 50,00±17,55 mg i 78,63±18,14 mg, dok su srednje doze diazepama u istim vremenskim tačkama bile 35,92±10,47 mg, 33,89±9,23 mg, 28,33±11,55 mg i 28,12±11,67 mg. Srednje koncentracije metadona su u posmatranim tačkama ispitivanja iznosile 153,44±111,51 ng/ml, 157,43±112,39 ng/ml, 176,77±118,56 ng/ml i 342,86±181,54 ng/ml, dok su srednje koncentracije diazepama bile 923,00±537,89 ng/ml, 923,76±739,96 ng/ml, 560,74±436,72 ng/ml i 1045,32±932,72 ng/ml. Dužina QTc intervala pre primene STM je bila 411,87±27,22 ms, tj. 414,64±29,38 ms 8. dana STM, 416,97±26,39 15. dana, i 425,20±17,71 ms nakon 1. meseca tj. 423,50±14,72 ms nakon 6. meseca primene STM. Pokazan je statistički značajan porast dužine QTc intervala nakon 1. i nakon 6. meseca primene STM u odnosu na vrednost pre primene STM, kako u grupi svih ispitanika, tako i u podgrupi muškog pola. Pokazano je postojanje statistički značajne korelacije između koncentracije metadona i dužine QTc intervala nakon 15. dana, 1. i 6. meseca primene STM, kako kod svih ispitanika, tako i u podgrupi muškog pola. Ova korelacija ostaje statistički značajna i ukoliko se uključe i drugi faktori – koncentracija diazepama i dužina perioda upotrebe heroina, kod svih ispitanika i u podgrupi muškog pola nakon 15 dana i mesec dana primene STM, kao i u podgrupi muškog pola nakon 6. meseca STM. Iako nijedan pacijent nije prijavio neko neželjeno delovanje metadona na nivou kardiovaskularnog sistema, najveći broj pacijenata oba pola se nakon prvog meseca primene STM žalio na pojačano znojenje i opstipaciju. Koncentracije metadona i diazepama u uzorcima krvi kod MRDs se nalaze u rasponu koncentracija ovih lekova u krvi ispitanika koji su učestvovali u prospektivnoj studiji. Trećina umrlih je imala samo znake akutnog oštećenja srca, dok do porasta troponina i vrednosti QTc intervala preko 500 ms nije došlo ni kod jednog ispitanika iz prospektivne studije. Potrebno je sprovesti dalja istraživanja sa ciljem razjašnjenja moguće uloge benzodiazepina u povećanju kardiotoksičnosti metadona kod opijatnih zavisnika na STM.
Methadone is a synthetic agonist of opioid receptors which is used in methadone maintenance tratment (MMT) of opiate addicts as well as in the treatment of chronic pain. A long-term use of MMT is followed by mild, mostly transient, adverse effects. However, methadone belongs to a group of medicines which can provoke a prolongation of QTc (corrected QT) interval in electrocardiogram (ECG) and thus increase the risk from the development of potentially fatal arrhythmias – torsades de pointes. Moreover, methadone is widely associated with benzodiazepines use in heroin addicts, and this combination is considered as a risk factor for lethal outcome. Despite the fact that most of health care professionals are aware of possible respiratory depressant effect of methadone and benzodiazepines co-administration, recently published data reveal that ventricular arrhythmia and cardiac arrest are currently the most frequent adverse event attributed to methadone and benzodiazepine co-medication. The aim of this study is to assess cardiac safety of methadone use, especially in combination with benzodiazepines, by analyzing characteristics of methadone-related deaths (MRDs) during 10-year period as well as by conducting a clinical trial among opiate addicts in MMT. A retrospective study to determine the characteristics of MRDs in Vojvodina, as well as a clinical trial in which participated opiate addicts at the start of MMT were performed. ECG (to calculate QTc interval) and blood sampling (to determine methadone and diazepam concentrations and troponin values) were performed in all study participants at five time points (before the introduction of MMT, on 8th, on 15th day, after 1 and 6 months of MMT). Methadone and diazepam concentrations in serum were determined by using liquid chromatography-mass spectrometry (LC-MS). An increasing tendency of MRDs was observed in the region of Vojvodina, but none of the victims were under healthcare professionals’ control, and, most commonly, they used methadone and benzodiazepines, on their own initiative. Pathohistological findings in the heart in MRDs might support cardiac adverse effects of methadone and its combination with benzodiazepines, especially in cases with acute myocardial damage. As for the chronic heart changes, we can neither confirm nor exclude the role of psychostimulants. Detected concentrations of methadone and diazepam were in therapeutic range (<1 μg/ml). Comparing socio-demographic characteristics of opiate addicts who started with MMT in this study with data from similar studies conducted worldwide, the similarity in terms of large number of features was observed. The mean methadone dose on the 8th, 15th days, and after 1 and 6 months of MMT was 40.23±17.11 mg, 47.11±16.79 mg, 50.00±17.55 mg and 78.63±18.14 mg, respectively, while the mean diazepam dose at the same time points was 35.92±10.47 mg, 33.89±9.23 mg, 28.33±11.55 mg and 28.12±11.67 mg, respectively. The mean methadone concentration at observed time points was 153.44±111.51 ng/ml, 157.43±112.39 ng/ml, 176.77±118.56 ng/ml and 342.86±181.54 ng/ml, respectively, while the mean diazepam concentration was 923.00±537.89 ng/ml, 923.76±739.96 ng/ml, 560.74±436.72 ng/ml and 1045.32±932.72 ng/ml, respectively. The length of QTc interval before the introduction of MMT was 411.87±27.22 ms, 414.64±29.38 ms on the 8th day of MMT, 416.97±26.39 on the 15th day of MMT, after 1 month of MMT 425.20±17.71 ms and after 6 months of MMT 423.50±14.72 ms. There was a statistically significant increase in the length of QTc interval after 1 and 6 months of MMT in comparison to the value before the application of MMT, within the whole group of patients and in the subgroup of men. A statistically significant correlation between the concentration of methadone and QTc interval length after 15 days, 1 and 6 months of MMT, both in the whole group and in the subroup of men was observed. The correlation remained statistically significant if the other factors, such as concentration of diazepam and the length of heroin use, were included, in all patients and in the subgroup of men after 15 days and one month of MMT as well as in the subgroup of men after 6 months of MMT. Although none of the patients reported any cardiac adverse effect of methadone, the majority of them complained of sweating and constipation after the first month of MMT. Concentrations of methadone and diazepam in blood samples in MRDs were within the range of concentrations of these drugs in blood of patients who participated in the prospective study. In one third of MRDs only signs of acute myocardial damage were detected, while an increase in troponin values and the length of QTc interval over 500 ms did not occur in any patient in the prospective study. Further studies could clarify the possible role of benzodiazepines in the increasing cardiotoxicity of methadone in opiate addicts in MMT.

This study investigated the ecology of dugongs in Moreton Bay, a 1400 km2 embayment in sub-tropical south-east Queensland (27.5" S, 153.3" E). The dugongs' distribution, movements, home range, habitat selection, feeding, diet and food preferences were examined in relation to the seagrass and physical resources. I considered the ways in which dugongs affect the seagrasses and the significance of the dugongs' role in the seagrass system. Seagrasses were quantitatively mapped in two study areas, encompassing 133 krn2 of seagrass. Seven species of seagrass formed 15 recognised communities, which collapsed into five community-groups. Communities dominated by species of Halophila were the most widespread, covering 51 % of the total area of seagrass, but they were characterised by low biomass, and accounted for only 9% of the total standing crop of seagrass (total = 12,808 tonnes dry weight). In comparison, communities dominated by Zostera capricorni (broad-leaf morph) occupied only 38% of the area of seagrass, but contained 75% of the seagrass standing crop. The annual, above-ground production of seagrass within the study areas was estimated to be 41,728 tonnes dry weight. Zostera capricorni, the dominant species in terms of biomass (57.5% of total above-ground standing crop), accounted for 34% of the total, while the species of Halophila accounted for 36.6 % , despite representing only 20.5 % of above-ground standing crop. The distinct seasonality of Moreton Bay was highly correlated with pronounced changes in seagrass abundance. There was a distinct summer/autumn peak in the abundance of most species. Zostera capricorni alone had a winterlspring growth period. Averaged across all species, shoot density, above-ground and belowground biomass changed by factors of 1.9, 2.3 and 2.3, respectively, between seasons of minimum and maximum abundance. Based on 28 aerial surveys, I estimate a Moreton Bay population of 600 dugongs. During spring and summer the dugongs were relatively sedentary, however, during winter the dugongs undertook regular migrations between the feeding areas inside the Bay and the oceanic waters east of the Bay (15-40 km round-trip). By riding the flood and ebb tides in and out of the Bay, the dugongs could exploit the temperature differential of up to 5" C between areas. Sometimes they spent as little as 1.5 hr, during the top of the tide, feeding in the Bay. Some dugongs stayed in the warm water outside the Bay for days at a time in winter. Thirteen dugongs occupied an average range of 64 km2 during the periods they were satellite-tracked (mean = 50 days). Within their home range, some dugongs sequentially used distinct sub-ranges, in which they concentrated their activities for periods of up to 35 days. Some areas were rarely, if ever used by dugongs, while other areas were

This study investigated the ecology of dugongs in Moreton Bay, a 1400 km2 embayment in sub-tropical south-east Queensland (27.5" S, 153.3" E). The dugongs' distribution, movements, home range, habitat selection, feeding, diet and food preferences were examined in relation to the seagrass and physical resources. I considered the ways in which dugongs affect the seagrasses and the significance of the dugongs' role in the seagrass system. Seagrasses were quantitatively mapped in two study areas, encompassing 133 krn2 of seagrass. Seven species of seagrass formed 15 recognised communities, which collapsed into five community-groups. Communities dominated by species of Halophila were the most widespread, covering 51 % of the total area of seagrass, but they were characterised by low biomass, and accounted for only 9% of the total standing crop of seagrass (total = 12,808 tonnes dry weight). In comparison, communities dominated by Zostera capricorni (broad-leaf morph) occupied only 38% of the area of seagrass, but contained 75% of the seagrass standing crop. The annual, above-ground production of seagrass within the study areas was estimated to be 41,728 tonnes dry weight. Zostera capricorni, the dominant species in terms of biomass (57.5% of total above-ground standing crop), accounted for 34% of the total, while the species of Halophila accounted for 36.6 % , despite representing only 20.5 % of above-ground standing crop. The distinct seasonality of Moreton Bay was highly correlated with pronounced changes in seagrass abundance. There was a distinct summer/autumn peak in the abundance of most species. Zostera capricorni alone had a winterlspring growth period. Averaged across all species, shoot density, above-ground and belowground biomass changed by factors of 1.9, 2.3 and 2.3, respectively, between seasons of minimum and maximum abundance. Based on 28 aerial surveys, I estimate a Moreton Bay population of 600 dugongs. During spring and summer the dugongs were relatively sedentary, however, during winter the dugongs undertook regular migrations between the feeding areas inside the Bay and the oceanic waters east of the Bay (15-40 km round-trip). By riding the flood and ebb tides in and out of the Bay, the dugongs could exploit the temperature differential of up to 5" C between areas. Sometimes they spent as little as 1.5 hr, during the top of the tide, feeding in the Bay. Some dugongs stayed in the warm water outside the Bay for days at a time in winter. Thirteen dugongs occupied an average range of 64 km2 during the periods they were satellite-tracked (mean = 50 days). Within their home range, some dugongs sequentially used distinct sub-ranges, in which they concentrated their activities for periods of up to 35 days. Some areas were rarely, if ever used by dugongs, while other areas were

Dugongs are large primary consumers of seagrass communities, and thereby shape the diversity, structure, and dynamics of these extensive ecosystems. The dugong is listed as vulnerable to extinction at a global scale. Because dugongs are seagrass specialists, understanding the interaction between dugongs and their seagrass habitats is crucial to their conservation. Habitat use by dugongs is beginning to receive greater attention by managers and ecologists, but a spatially-explicit model capable of predicting usage by dugongs based on attributes of those habitats is lacking. Studying the interaction between dugongs and their seagrass food requires knowledge of the movements and diving behaviour of dugongs at scales relevant to both dugongs and managers. Information is needed on dugong spatial patterns, including movement behaviours and habitat use, across domains of scale. Multi-scale approaches to dugong research have not been possible in the past because of the difficulties in observing dugongs directly and the low resolution of telemetric equipment. My project capitalised on recent technology incorporating accurate GPS technology into tracking equipment to monitor the habitat use of wild animals at very high resolution (<10 m). Advances in geographic information systems (GIS) and spatial modelling enabled habitat selection by satellite-tracked dugongs to be analysed in a high-resolution, spatially explicit manner. I used hierarchical scales of spatial analyses to assess the relative importance of different seagrass meadows and parts of meadows to dugongs at scales that are suitable for informing policy concerning the management of human activities. My central research hypotheses were that: (1) dugongs forage like terrestrial mammalian grazers in that they prefer habitats where their foraging efficiency is greatest and (2) patterns of dugong movements and habitat use across spatial scales are intimately linked to the availability and distribution of quality seagrass forage. I investigated the mechanisms that produce the large-scale distribution and movement patterns of dugongs by reanalysing the results of historical aerial surveys and satellite tracking conducted by earlier researchers in combination with new data from my GPS telemetry of 20 dugongs in sub-tropical and tropical waters of Queensland and the Northern Territory, Australia. The mean patch size supporting high relative density (> 0.1 dugongs/km2) of dugongs over 20 years along the urban coast of Queensland was 77 km2 (± 4 s.e.). Hence, at regional and landscape scales (> 100 km2) dugongs select habitat at the level of individual bays along the coast. The tracked dugongs were followed for periods ranging from 15 to 551 days and exhibited a large range of individualistic movement behaviours; 26 individuals were relatively sedentary (moving < 15 km) while 44 made large-scale movements (> 15 km) of up to 560 km from their capture sites. Male and female animals, including cows with calves, undertook large-scale movements (LSM; > 15 km). At least some of these movements were return movements to the capture location, suggesting that such movements were ranging rather than dispersal movements. Large-scale movements included macro-scale regional movements (> 100 km) and meso-scale inter-patch local movements (15 ≤ 100 km) and were qualitatively different from tidally-driven micro-scale commuting movements between and within seagrass beds (< 15 km). Large-scale movements were rapid and apparently directed. Tracked dugongs rarely travelled far from the coast (mean max distance = 12.8 ± s.e. 1.3 km). Dive profiles from the timedepth recorders suggest that dugongs make repeated deep dives while travelling rather than remaining at the surface. Some animals caught in the high latitude limits of the dugongs’ range on the Australian east coast in winter apparently undertook long distance movements in response to low water temperatures, similar to the seasonal movements of Florida manatees. A 24 km2 seagrass meadow in Hervey Bay, Queensland, Australia was confirmed as important dugong habitat on the basis of the tracking data. Marine videography, Near-infrared Spectroscopy (NIRS) and Geographic Information Systems (GIS) were used to survey, analyse and map seagrass species composition, nutrient profile and patch structure of the meadow at high resolution (200 m). Five species of seagrass covered 91 % of the total habitat area. The total above and below-ground seagrass biomass was estimated to be 222.7 ± s.e. 19.6 t dry-weight. Halodule uninervis dominated the pasture (81.8 %, 162.2 t), followed by Halophila ovalis (35.3 %, 16.5 t), Zostera capricorni (15.9 %, 22.2 t), Halophila spinulosa (14.5 %, 21.9 t), and traces of Halodule pinifolia. Because the distributions of the various seagrass species overlapped, their combined percentage totalled > 100 % of the survey area. The seagrass formed a continuous meadow of varying density. For all seagrass species, the above-ground component (shoots and leaves) possessed greater total nitrogen than the below-ground component (roots and rhizomes), which possessed greater total starch. Because of the relatively low intraspecific variation in nutrient composition, nutrients were concentrated according to seagrass biomass density. H. uninervis was the most nutritious seagrass species because of its higher whole-plant nitrogen (1.28 ± s.e. 0.05 % DW) and starch (6.42 ± s.e. 0.50 DW %) content. H. uninervis formed large, clustered patches of dense biomass across the pasture and thus nitrogen and starch were concentrated where H. uninervis was prevalent. These survey and analytical techniques enabled me to rapidly, economically and accurately quantify and characterise seagrass habitat at scales relevant to a large forager. I used GIS and spatial statistics to identify the role of physical environmental characteristics in determining the activity patterns and fine-scale space-use of dugongs tracked in coastal and deepwater seagrass habitats using GPS telemetry. A seagrass meadow was defined as a core dugong habitat if more than 10 days of satellite location fixes were obtained from an individual animal occupying an area <100 km2. Habitats were categorised as inshore/intertidal or offshore/subtidal depending on their distance to the shore and the water depth. Inshore/intertidal habitats had a shallow component that was exposed at low tide. Offshore/subtidal habitats were at least 5 km from the nearest mainland and were at least 3 m deep at mean low water spring tide (MLWS). Location fixes acquired from dugongs tracked in coastal habitats exhibited significant circadian rhythms, with fewer locations during the morning than during late afternoon/night. GPS location fixes could only be acquired when the transmitter was at the surface. Such periods are typically brief, as when the animal surfaces to breathe. More GPS locations were acquired from inshore/intertidal dugongs that were foraging in the intertidal zone than from animals in the subtidal zone. This telemetric artefact provided an indication of when the animals were moving across shallow intertidal waters. More locations were received at night when the animals were generally closest to the shore and in shallow water and fewer locations were received during the day when animals were further subtidal in deeper waters. Hence, the average depth of water experienced by dugongs and their distances from the shore may have been significantly underestimated, especially when fix success was low, since animals that were in shallower water were more likely to be sampled. Consequently, my estimates of the diel patterns of dugong space use were more conservative than the actual situation and probably underestimated the strength of the tidal patterns. Dugongs were in deeper water more often during the morning than during late afternoon/night. There was no effect of tide height on the actual depths in which dugongs occurred. Dugongs in coastal habitats were furthest from the shore between 6:00am and 12:00pm and closest between 3:00pm and 12:00am. Dugongs were closer to the shore during high tide than during low tide. Physical environment variables had little or no effect on the spatial patterns of dugongs tracked in deep water. The movement speeds of the coastal and deepwater dugongs increased marginally between 9:00am and 3:00pm, from an average of 200 to 300 m/hr. Seven dugongs were GPS tracked at a fine spatial scale (< 10m) within the Burrum seagrass habitat in winter. Resource selection within the habitat was modelled by comparing the dugongs’ use of space with the distribution of their seagrass food resources within an area defined using the combined space-use of the tracked animals. The association of dugongs with seagrass quantity (biomass) and quality (nutrients) was analysed within six time/tide combinations to examine the influences of tidal periodicity and the diel cycle on resource selection. I used resource utilisation functions (RUFs) to relate a probabilistic measure of each individual dugong’s space-use in each time/tide combination in a utilisation distribution (UD) (dependent variable) to the spatial landscapes of the resource variables (independent variables) using multiple regression. The RUF models indicated that dugong space-use was consistently centred over seagrass patches with high nitrogen concentrations, except during the day at low tides when their space-use was centred over high seagrass biomass and away from seagrass with high starch concentration. Dugong association with seagrass high in starch was positive during both day and night high tides when dugongs could access intertidal areas where the seagrass biomass was generally low. Patterns of association with seagrass species were less definite. Estimates of the intensity of dugong space-use in relation to available seagrass resources may be confounded by the differentiation of fix probability by depth and speed. Because my estimates of dugong space-use in relation to subtidal seagrass may have been more conservative than the data suggested, the positive association of dugongs with patches of high biomass seagrass and avoidance of patches containing H. spinulosa and Z. capricorni in the subtidal zone may have been over-estimated by this sampling bias. I posit that dugong habitat selection and resource use occur hierarchically, across (at least) three different domains of scale: (1)at a regional-scale (> 10 000 km2) dugongs select habitat at the level of individual bays along the Queensland coast; (2) at a landscape-scale (< 10 000 km2), dugongs select seagrass pastures within bays along the Queensland coast comprised of nutritious plant species; (3) at a local-scale (< 10 km2) within seagrass pastures that are within bays along the Queensland coast, dugongs select seagrass patches on the basis of their nutrient concentrations. I recommend that the appropriate scales at which to manage dugong populations and their seagrass habitats be co-ordinated within and across the hierarchical scales of habitat use indicated by my analysis. My finding that dugongs frequently undertake large-scale moves has implications for management at a range of scales, and strengthens the aerial survey and genetic evidence for management and monitoring at ecological scales that cross jurisdictions. The capacity of large-scale monitoring programs to detect trends in dugong numbers at scales of even thousands of km2 is confounded by the dugongs' tendency to undertake large-scale moves. With movement between bays a common occurrence, estimates of population size and trends can only be meaningfully made at regional scales. The tendency for dugongs to track the bottom on large-scale movements may increase their vulnerability to incidental capture in bottom set gill nets. In addition, if dugongs transfer their spatial knowledge of the location of quality food resource patches to their offspring, then local depletions will lead to loss of this knowledge. Areas of high quality seagrass may thus become unknown to dugongs. In the absence of grazing pressure such areas may become less valuable as dugong habitat if the early seral stage species of seagrass preferred by dugongs convert to more fibrous species. My research suggests that dugongs actively select seagrass habitats comprised primarily of H. ovalis and H. uninervis, based on the high starch and nitrogen content of these species. Bays containing these quality food resources comprise an interlinked network of core habitats between which dugongs frequently move. Accordingly, bays along the Queensland coast with seagrass meadows dominated by H. ovalis and H. uninervis should be afforded a high level of protection as potential quality dugong habitat. Bays with extensive intertidal meadows of H. uninervis should also receive enhanced protection, even if the seagrass biomass is low. Even though they have low seagrass biomass, thermoregulatory habitats play an important role in maintaining dugong populations and should be included in dugong habitat protection strategies.

Dugongs are large primary consumers of seagrass communities, and thereby shape the diversity, structure, and dynamics of these extensive ecosystems. The dugong is listed as vulnerable to extinction at a global scale. Because dugongs are seagrass specialists, understanding the interaction between dugongs and their seagrass habitats is crucial to their conservation. Habitat use by dugongs is beginning to receive greater attention by managers and ecologists, but a spatially-explicit model capable of predicting usage by dugongs based on attributes of those habitats is lacking. Studying the interaction between dugongs and their seagrass food requires knowledge of the movements and diving behaviour of dugongs at scales relevant to both dugongs and managers. Information is needed on dugong spatial patterns, including movement behaviours and habitat use, across domains of scale. Multi-scale approaches to dugong research have not been possible in the past because of the difficulties in observing dugongs directly and the low resolution of telemetric equipment. My project capitalised on recent technology incorporating accurate GPS technology into tracking equipment to monitor the habitat use of wild animals at very high resolution (<10 m). Advances in geographic information systems (GIS) and spatial modelling enabled habitat selection by satellite-tracked dugongs to be analysed in a high-resolution, spatially explicit manner. I used hierarchical scales of spatial analyses to assess the relative importance of different seagrass meadows and parts of meadows to dugongs at scales that are suitable for informing policy concerning the management of human activities. My central research hypotheses were that: (1) dugongs forage like terrestrial mammalian grazers in that they prefer habitats where their foraging efficiency is greatest and (2) patterns of dugong movements and habitat use across spatial scales are intimately linked to the availability and distribution of quality seagrass forage. I investigated the mechanisms that produce the large-scale distribution and movement patterns of dugongs by reanalysing the results of historical aerial surveys and satellite tracking conducted by earlier researchers in combination with new data from my GPS telemetry of 20 dugongs in sub-tropical and tropical waters of Queensland and the Northern Territory, Australia. The mean patch size supporting high relative density (> 0.1 dugongs/km2) of dugongs over 20 years along the urban coast of Queensland was 77 km2 (± 4 s.e.). Hence, at regional and landscape scales (> 100 km2) dugongs select habitat at the level of individual bays along the coast. The tracked dugongs were followed for periods ranging from 15 to 551 days and exhibited a large range of individualistic movement behaviours; 26 individuals were relatively sedentary (moving < 15 km) while 44 made large-scale movements (> 15 km) of up to 560 km from their capture sites. Male and female animals, including cows with calves, undertook large-scale movements (LSM; > 15 km). At least some of these movements were return movements to the capture location, suggesting that such movements were ranging rather than dispersal movements. Large-scale movements included macro-scale regional movements (> 100 km) and meso-scale inter-patch local movements (15 ≤ 100 km) and were qualitatively different from tidally-driven micro-scale commuting movements between and within seagrass beds (< 15 km). Large-scale movements were rapid and apparently directed. Tracked dugongs rarely travelled far from the coast (mean max distance = 12.8 ± s.e. 1.3 km). Dive profiles from the timedepth recorders suggest that dugongs make repeated deep dives while travelling rather than remaining at the surface. Some animals caught in the high latitude limits of the dugongs’ range on the Australian east coast in winter apparently undertook long distance movements in response to low water temperatures, similar to the seasonal movements of Florida manatees. A 24 km2 seagrass meadow in Hervey Bay, Queensland, Australia was confirmed as important dugong habitat on the basis of the tracking data. Marine videography, Near-infrared Spectroscopy (NIRS) and Geographic Information Systems (GIS) were used to survey, analyse and map seagrass species composition, nutrient profile and patch structure of the meadow at high resolution (200 m). Five species of seagrass covered 91 % of the total habitat area. The total above and below-ground seagrass biomass was estimated to be 222.7 ± s.e. 19.6 t dry-weight. Halodule uninervis dominated the pasture (81.8 %, 162.2 t), followed by Halophila ovalis (35.3 %, 16.5 t), Zostera capricorni (15.9 %, 22.2 t), Halophila spinulosa (14.5 %, 21.9 t), and traces of Halodule pinifolia. Because the distributions of the various seagrass species overlapped, their combined percentage totalled > 100 % of the survey area. The seagrass formed a continuous meadow of varying density. For all seagrass species, the above-ground component (shoots and leaves) possessed greater total nitrogen than the below-ground component (roots and rhizomes), which possessed greater total starch. Because of the relatively low intraspecific variation in nutrient composition, nutrients were concentrated according to seagrass biomass density. H. uninervis was the most nutritious seagrass species because of its higher whole-plant nitrogen (1.28 ± s.e. 0.05 % DW) and starch (6.42 ± s.e. 0.50 DW %) content. H. uninervis formed large, clustered patches of dense biomass across the pasture and thus nitrogen and starch were concentrated where H. uninervis was prevalent. These survey and analytical techniques enabled me to rapidly, economically and accurately quantify and characterise seagrass habitat at scales relevant to a large forager. I used GIS and spatial statistics to identify the role of physical environmental characteristics in determining the activity patterns and fine-scale space-use of dugongs tracked in coastal and deepwater seagrass habitats using GPS telemetry. A seagrass meadow was defined as a core dugong habitat if more than 10 days of satellite location fixes were obtained from an individual animal occupying an area <100 km2. Habitats were categorised as inshore/intertidal or offshore/subtidal depending on their distance to the shore and the water depth. Inshore/intertidal habitats had a shallow component that was exposed at low tide. Offshore/subtidal habitats were at least 5 km from the nearest mainland and were at least 3 m deep at mean low water spring tide (MLWS). Location fixes acquired from dugongs tracked in coastal habitats exhibited significant circadian rhythms, with fewer locations during the morning than during late afternoon/night. GPS location fixes could only be acquired when the transmitter was at the surface. Such periods are typically brief, as when the animal surfaces to breathe. More GPS locations were acquired from inshore/intertidal dugongs that were foraging in the intertidal zone than from animals in the subtidal zone. This telemetric artefact provided an indication of when the animals were moving across shallow intertidal waters. More locations were received at night when the animals were generally closest to the shore and in shallow water and fewer locations were received during the day when animals were further subtidal in deeper waters. Hence, the average depth of water experienced by dugongs and their distances from the shore may have been significantly underestimated, especially when fix success was low, since animals that were in shallower water were more likely to be sampled. Consequently, my estimates of the diel patterns of dugong space use were more conservative than the actual situation and probably underestimated the strength of the tidal patterns. Dugongs were in deeper water more often during the morning than during late afternoon/night. There was no effect of tide height on the actual depths in which dugongs occurred. Dugongs in coastal habitats were furthest from the shore between 6:00am and 12:00pm and closest between 3:00pm and 12:00am. Dugongs were closer to the shore during high tide than during low tide. Physical environment variables had little or no effect on the spatial patterns of dugongs tracked in deep water. The movement speeds of the coastal and deepwater dugongs increased marginally between 9:00am and 3:00pm, from an average of 200 to 300 m/hr. Seven dugongs were GPS tracked at a fine spatial scale (< 10m) within the Burrum seagrass habitat in winter. Resource selection within the habitat was modelled by comparing the dugongs’ use of space with the distribution of their seagrass food resources within an area defined using the combined space-use of the tracked animals. The association of dugongs with seagrass quantity (biomass) and quality (nutrients) was analysed within six time/tide combinations to examine the influences of tidal periodicity and the diel cycle on resource selection. I used resource utilisation functions (RUFs) to relate a probabilistic measure of each individual dugong’s space-use in each time/tide combination in a utilisation distribution (UD) (dependent variable) to the spatial landscapes of the resource variables (independent variables) using multiple regression. The RUF models indicated that dugong space-use was consistently centred over seagrass patches with high nitrogen concentrations, except during the day at low tides when their space-use was centred over high seagrass biomass and away from seagrass with high starch concentration. Dugong association with seagrass high in starch was positive during both day and night high tides when dugongs could access intertidal areas where the seagrass biomass was generally low. Patterns of association with seagrass species were less definite. Estimates of the intensity of dugong space-use in relation to available seagrass resources may be confounded by the differentiation of fix probability by depth and speed. Because my estimates of dugong space-use in relation to subtidal seagrass may have been more conservative than the data suggested, the positive association of dugongs with patches of high biomass seagrass and avoidance of patches containing H. spinulosa and Z. capricorni in the subtidal zone may have been over-estimated by this sampling bias. I posit that dugong habitat selection and resource use occur hierarchically, across (at least) three different domains of scale: (1)at a regional-scale (> 10 000 km2) dugongs select habitat at the level of individual bays along the Queensland coast; (2) at a landscape-scale (< 10 000 km2), dugongs select seagrass pastures within bays along the Queensland coast comprised of nutritious plant species; (3) at a local-scale (< 10 km2) within seagrass pastures that are within bays along the Queensland coast, dugongs select seagrass patches on the basis of their nutrient concentrations. I recommend that the appropriate scales at which to manage dugong populations and their seagrass habitats be co-ordinated within and across the hierarchical scales of habitat use indicated by my analysis. My finding that dugongs frequently undertake large-scale moves has implications for management at a range of scales, and strengthens the aerial survey and genetic evidence for management and monitoring at ecological scales that cross jurisdictions. The capacity of large-scale monitoring programs to detect trends in dugong numbers at scales of even thousands of km2 is confounded by the dugongs' tendency to undertake large-scale moves. With movement between bays a common occurrence, estimates of population size and trends can only be meaningfully made at regional scales. The tendency for dugongs to track the bottom on large-scale movements may increase their vulnerability to incidental capture in bottom set gill nets. In addition, if dugongs transfer their spatial knowledge of the location of quality food resource patches to their offspring, then local depletions will lead to loss of this knowledge. Areas of high quality seagrass may thus become unknown to dugongs. In the absence of grazing pressure such areas may become less valuable as dugong habitat if the early seral stage species of seagrass preferred by dugongs convert to more fibrous species. My research suggests that dugongs actively select seagrass habitats comprised primarily of H. ovalis and H. uninervis, based on the high starch and nitrogen content of these species. Bays containing these quality food resources comprise an interlinked network of core habitats between which dugongs frequently move. Accordingly, bays along the Queensland coast with seagrass meadows dominated by H. ovalis and H. uninervis should be afforded a high level of protection as potential quality dugong habitat. Bays with extensive intertidal meadows of H. uninervis should also receive enhanced protection, even if the seagrass biomass is low. Even though they have low seagrass biomass, thermoregulatory habitats play an important role in maintaining dugong populations and should be included in dugong habitat protection strategies.

This study examined aspects of the interactions between dugongs, green turtles and their tropical seagrass food. In order to examine the effects of herbivory on the community structure, productivity, and nutritional composition of seagrass, experiments simulating intensive and light dugong grazing (uprooting whole plants) and intensive turtle cropping (removal of aboveground biomass) were carried out in intertidal seagrass beds at Cardwell (18°14'S, 146°E) and Ellie Point (16 ° 53 S, 145 ° 46 ' E) on the northeast Queensland coast. Grazing experiments at Cardwell and Ellie Point were monitored monthly for a year before the seagrass samples were harvested. An additional short-term experiment was also carried out at Cardwell only, wherein samples were harvested one month and two months after cropping, while those from the grazing plots were harvested after four months. Seagrasses were harvested opportunistically from eight sites and from four depths at one site to investigate specific and spatial variation in nutrient composition. The effect of artificial nitrogen and phosphorus fertiliser treatments on seagrass nutrients was investigated experimentally at Shelley Beach (19°19'S, 146°50'E). Determinants of the nutritional composition of tropical seagrasses and the nutritional basis of the observed feeding preference of these herbivores were also considered. Two techniques were used in seagrass ecology for the first time: (1) Video recording was used for monitoring temporal changes in the species composition and abundance in tropical seagrass communities; (2) Near infra-red reflectance spectroscopy (NIRS) was used to measure the concentrations of the following: nitrogen, organic matter, neutral detergent fibre, acid detergent fibre, lignin, water soluble carbohydrate, and starch and in vitro digestibility of dry matter. The development of the NIRS technique involved the collection of 10 species of seagrasses: Halophila ovalis, H minor, H spinulosa, H decipiens, H. trichostata, Halodule uninervis, Cymodocea serrulata, C. rotundata, Syringodium isoetifolium, and Zostera capricorni (with H uninervis and Z capricorni exhibiting two varieties). From this collection, a seagrass database consisting of 1,165 samples of leaves (n = 556), roots/rhizomes (n = 552), whole plant (n = 11), seeds (n = 3), and detrital matter (n= 43), including the samples from the grazing experiments, was developed. Then, using NIRS, the spectra of all samples were collected. From this spectral population, some 200 spectra representative of the whole population were selected, using a computer algorithm package (NIRS 3) as the calibration set and prediction equations (multivariate models) developed for the above seagrass nutritional components. The nature and extent of the effects of grazing and cropping were related to: (1) the intensity of the grazing impact; and (2) the nature of the seagrass community, including its species composition and location. In a mixed-species bed at Ellie Point, intensive grazing altered the species composition by promoting the growth of a more opportunistic (short-lived) species, Halophila ovalis in the spaces created by the grazing disturbance at the expense of a long-lived species, Zostera capricorni. Grazing also reduced the amounts of detrital matter. The species composition of a monospecific bed of Halodule uninervis was not affected by grazing. Both light and intensive grazing, and cropping increased the net above-ground biomass productivity of H. ovalis and Halodule uninervis. Recovery times varied from months for H. ovalis and Zostera/Cymodocea at Ellie Point to more than one year for H uninervis at Cardwell. In both cases, grazing improved the seagrass bed as grazing habitat for dugongs and green turtles. Simulated dugong grazing improved the nutritional composition (nitrogen and water soluble carbohydrate) of H. ovalis and H uninervis. This improvement was detectable 10 to 12 months later. In short-term experiments, both grazing and cropping increased the leaf nitrogen concentration of H uninervis. The digestibility (in vitro) of dry matter of H uninervis moderately increased after grazing and cropping. Grazing and cropping had variable effects on the fibre and lignin contents of H. uninervis depending on the plant part, nature and intensity of herbivory and duration of the recovery. Enhanced nutrients in the sediments increased the concentrations of nitrogen, starch, and fibre of H minor and H uninervis. The nutritional composition of seagrasses also varied between plant parts, among species, between varieties, among depths, and among locations (sites). Halophila species, together with Syringodium isoetifolium, were more digestible than Z. capricorni, C. serrulata, and C. rotundata, while Halodule uninervis had the highest nitrogen and starch concentrations of any of the species. Dugongs and green turtles appear to optimise their diet by selecting food species that maximise digestible nutrients. This is achieved by selecting seagrass species that are more digestible and have higher nutrients (e.g. nitrogen and carbohydrates/starch) and/or species which can compensate for grazing. Changes in feeding habitats due to herbivory by dugongs and green turtles affect the functional dynamics of tropical seagrass ecosystems through the alteration of resource availability and sediment redox conditions resulting from grazing disturbance. Consequently, mosaics of patches of varying species and nutritional compositions are produced at a local scale. A major and long-term reduction in the number of dugongs and green turtles in some areas may lead to an irreversible degradation of their habitats as preferred food species are replaced by less-preferred species. In other areas, other forms of natural disturbance and environmental constraints probably maintain the community at a low seral stage.

Dugongs (Dugong dugon) live in tropical inshore areas around Northern Australia and throughout the Indo-West Pacific. These marine mammals are obligate seagrass feeders and are thus largely restricted in distribution to areas of seagrass habitat. The turbid environment and the lack of a dorsal fin for individual identification makes it impractical to study these animals using standard observational methods. Consequently very little is known about dugong population structure and migration patterns. From satellite tracking of individuals and aerial surveys it appears that dugongs, like many other marine mammals, can move long distances, but the timing and length of movements vary individually. If dugongs move and mate in their new locality, there will be substantial gene flow across large spatial scales and very little population differentiation around the tropical Australian coast. However, if dugongs maintain a home range and are philopatric (i.e. any long distance movements are for food or other reasons not including mating), then there would be very limited gene flow and substantial structuring among populations. In order to ascertain which pattern of population structure is present in the dugong, I used a variety of molecular techniques to assess dugong population genetic structure around the North Australian coast. A comparison of the two published mitochondrial genomes of dugongs showed that most variation was contained within the control region. I subsequently characterised the entire control region of eight individual dugongs (four available from previous studies and four sequenced in this study) and identified the amount of variation among them. I also made a comparison of the mitochondrial control region of dugongs with available sequences of their closest relatives, the paenungulates (Proboscidea, Hyracoidea, and other members of the Sirenia), in order to assess whether the control region was capable of producing reasonable phylogenies and its usefulness as a marker for phylogeographic and population studies on the dugong. The 5’ domain of the control region was identified as the most appropriate section of this locus for use in the phylogeographic analysis. This domain demonstrates high diversity in the dugong. Phylogeographic analysis of the 492 bp alignment of 115 dugongs, identified two divergent Australian mitochondrial lineages. I hypothesise that the Australian lineages diverged historically during periods of low sea level that would have reduced habitat availability and produced geological barriers such as the Torres Strait land bridge between Northern Australia and Papua New Guinea. One lineage is restricted geographically to the coast of Queensland and into the Northern Territory, while the other is more widespread occurring from Shark Bay in Western Australia to Moreton Bay in Queensland (i.e. across the entire Australian range). The widespread lineage is poorly represented in Southeastern Queensland. Given the availability of continuous habitat with higher sea level for the past 7000 years and the high mobility of dugongs, I expected that more complete geographic mixing of lineages would have occurred. Mitochondrial DNA sequences of dugongs from Asia are distinct from those of Australian dugongs. These results suggest long-term isolation between dugong lineages and subsequent partial geographic mixing of dugong matrilines. Nuclear DNA microsatellite loci isolated from the Florida manatee were tested for use as population genetic markers the dugong. These loci displayed considerable allelic diversity in the dugong, significantly greater than observed in the Florida manatee. For example, 27 alleles were identified in the dugong at locus TmaA04, while only one allele was identified in the Florida manatee at the same locus. These microsatellite markers reveal a high level of gene flow among dugongs in Australia and a significant level of isolation-by-distance across Australia. Comparison of the results from mtDNA and nDNA indicate that members of the two distinct mitochondrial lineages within Australia interbreed in areas where they overlap geographically. The contrasting patterns of structure presented by the mtDNA and nDNA suggest male-biased gene flow in the dugong. This pattern has not yet been identified from ecological studies, but is consistent with common dispersal patterns in mammals. The major findings of this study are the detection of ‘healthy’ levels of genetic diversity of Australian dugongs, a suggestion of male-biased gene flow, and a demonstration of significant gene flow around Australia. This high level of gene flow makes the allocation of management units difficult. These results indicate the importance of a co-ordinated management strategy at a spatial scale of thousands of kilometres. Dugongs within Australia cannot be managed at a bay level due to the connectivity between bays observed in this study. Co-operation between management agencies at local, state, national and international spatial scales is required in order to conserve this vulnerable species.

Given the globally threatened status of dugongs and the fact that Torres Strait supports the world's largest dugong population, there is international, national, regional and local interest in ensuring the sustainability of the Torres Strait traditional dugong fishery. This fishery is endorsed by the Torres Strait Treafy between Australia and Papua New Guinea (PNG). This study investigated, within a biological context, the major factors (i.e., those additional to biological) that determine sustainability of the traditional dugong fishery in Torres Strait. My thesis had the following specific aims: (1) To provide information relevant to the development of community-based management for the dugong fishery in Torres Strait by: describing and quantifying the major factors that affect hunting pattern, hunting effort, hunting success and harvest levels in the major dugong hunting community of Mabuiag Island, and estimating the life history parameters of Torres Strait dugongs at the time of my study, and (i) comparing them with parameters obtained from parallel studies of dugong life history and reproductive biology in order to gain insights into the factors influencing these aspects of dugong ecology, and (ii) incorporating them into population models to predict the natural rate of change in the size of the population in the absence of hunting mortality. (2) To assist in the development of community-based management in Torres Strait through contributing to capacity building by actively involving Torres Strait Islanders in my research and training them in the collection of catch statistics and biological samples from dugongs. The fieldwork for this project was undertaken primarily at Mabuiag Island between September 1997 and November 1999 inclusive. All data and specimens from 127 female and 51 male dugongs were collected from animals butchered for food by Torres Strait Islander hunters. Being able to live and work within the Mabuiag Island community provided me with the rare opportunity to develop a relationship with Islanders built upon the mutual trust, co-operation and commitment. Involving Islanders as active participants in my research allowed me to collect the valuable specimens on which my information is based. The active involvement of hunters and community members enhanced their development of a sound understanding of and trust in the information I obtained. By training Torres Strait Islanders as research assistants, 1 also increased the capacity of the community to actively participate in future research, monitoring and management programs for dugongs. This study provided the opportunity to identify the main factors which impact catch rates of dugongs by Islanders. Only four to five hunters were responsible for 79% and 75% of the 145 and 170 dugongs taken at Mabuiag lsland during March to October in 1998 and 1999, respectively. The magnitude of the dugong catch was influenced by ecological, economic environmental and social factors that affected the temporal and spatial nature of hunting effort and hunting success. When my results were compared with those of other studies using similar techniques, I showed that the age and size at sexual maturity and first reproduction, pregnancy rates of female dugongs and the sex ratio of their young exhibit considerable variability in both space and time. The age and size at sexual maturity and first reproduction of male dugongs exhibit similar variability. At Mabuiag lsland in 1997-99, female dugongs reached sexual maturity between six or seven and fourteen years and at body lengths of between 2.05 and 2.58 m. Male dugongs reached sexual maturity between four and thirteen years and at body lengths between 1.90 and 2.57 m. Calving intervals of adult female dugongs from Mabuiag lsland in 1998-99 ranged between 2.4 f s.e. 0.3 to 3.3 f s.e. 0.5 years. The parameters from Mabuiag lsland in 1997-98 are thus the lowest recorded for dugongs. At Mabuiag lsland in 1997-98, almost all sexually mature nulliparous females were either pregnant andlor lactating and the sex ratio of foetuses was 1:3 in favour of males. Variability in life history parameters such as age at sexual maturity and first reproduction, pregnancy rates and calving intervals in dugongs is likely to result from spatial and temporal variation in seagrass community composition and biomass. Thus, food quality and availability influence dugong population dynamics. When their seagrass food disappears as a result of episodic disturbance, some dugongs suspend breeding. It is likely that the effects of food supply on life history parameters and hence fecundity in dugongs includes both density dependent and density independent components. The gaps in the age composition of the catch from Mabuiag in 1997-99 together with the low pregnancy rates of animals caught in the Daru market at that time suggest that a seagrass dieback in Torres Strait in the late 1970s had significant effects on dugong recruitment. These links between seagrass food availability and dugong life history parameters have very important implications for management given the dugong's susceptibility to large-scale episodic losses of seagrass. Several findings in this study highlight that a regional approach to management will be required because the potential for episodic or longer-tern over-harvesting can be exacerbated in the event of a combination of: low dugong fecundity as a result of extensive seagrass dieback events such as that reported in the 1970s; movements of dugongs close to hunting communities to feed on intertidal seagrass in response to dieback of deepwater communities exacerbating high hunting pressure; increase in hunting pressure in response to reduction in important sources of income such as the cray fishery. Management coordinated at a regional scale must include the Northern Peninsula Area of Cape York and PNG. Management will need to build on established processes which incorporate Ailan Kast'om (the customary way of life of Torres Strait Islanders) and institutional structures in the Torres Strait region which include the: Torres Sfraif Treafy, Torres Sfraif Fisheries Acf (1984), Native Title and regional Islander initiatives such as MaSTERS (Marine Strategy for Torres Strait). A community-based management approach, which builds on the research processes, and the empirical information obtained in this study, has considerable potential to ensure that the Torres Strait dugong fishery is sustainable. The challenge now is to build on information and trust generated by this project by enabling Islanders to use these results to develop and implement appropriate management plans for their dugong resources.

Given the globally threatened status of dugongs and the fact that Torres Strait supports the world's largest dugong population, there is international, national, regional and local interest in ensuring the sustainability of the Torres Strait traditional dugong fishery. This fishery is endorsed by the Torres Strait Treafy between Australia and Papua New Guinea (PNG). This study investigated, within a biological context, the major factors (i.e., those additional to biological) that determine sustainability of the traditional dugong fishery in Torres Strait. My thesis had the following specific aims: (1) To provide information relevant to the development of community-based management for the dugong fishery in Torres Strait by: describing and quantifying the major factors that affect hunting pattern, hunting effort, hunting success and harvest levels in the major dugong hunting community of Mabuiag Island, and estimating the life history parameters of Torres Strait dugongs at the time of my study, and (i) comparing them with parameters obtained from parallel studies of dugong life history and reproductive biology in order to gain insights into the factors influencing these aspects of dugong ecology, and (ii) incorporating them into population models to predict the natural rate of change in the size of the population in the absence of hunting mortality. (2) To assist in the development of community-based management in Torres Strait through contributing to capacity building by actively involving Torres Strait Islanders in my research and training them in the collection of catch statistics and biological samples from dugongs. The fieldwork for this project was undertaken primarily at Mabuiag Island between September 1997 and November 1999 inclusive. All data and specimens from 127 female and 51 male dugongs were collected from animals butchered for food by Torres Strait Islander hunters. Being able to live and work within the Mabuiag Island community provided me with the rare opportunity to develop a relationship with Islanders built upon the mutual trust, co-operation and commitment. Involving Islanders as active participants in my research allowed me to collect the valuable specimens on which my information is based. The active involvement of hunters and community members enhanced their development of a sound understanding of and trust in the information I obtained. By training Torres Strait Islanders as research assistants, 1 also increased the capacity of the community to actively participate in future research, monitoring and management programs for dugongs. This study provided the opportunity to identify the main factors which impact catch rates of dugongs by Islanders. Only four to five hunters were responsible for 79% and 75% of the 145 and 170 dugongs taken at Mabuiag lsland during March to October in 1998 and 1999, respectively. The magnitude of the dugong catch was influenced by ecological, economic environmental and social factors that affected the temporal and spatial nature of hunting effort and hunting success. When my results were compared with those of other studies using similar techniques, I showed that the age and size at sexual maturity and first reproduction, pregnancy rates of female dugongs and the sex ratio of their young exhibit considerable variability in both space and time. The age and size at sexual maturity and first reproduction of male dugongs exhibit similar variability. At Mabuiag lsland in 1997-99, female dugongs reached sexual maturity between six or seven and fourteen years and at body lengths of between 2.05 and 2.58 m. Male dugongs reached sexual maturity between four and thirteen years and at body lengths between 1.90 and 2.57 m. Calving intervals of adult female dugongs from Mabuiag lsland in 1998-99 ranged between 2.4 f s.e. 0.3 to 3.3 f s.e. 0.5 years. The parameters from Mabuiag lsland in 1997-98 are thus the lowest recorded for dugongs. At Mabuiag lsland in 1997-98, almost all sexually mature nulliparous females were either pregnant andlor lactating and the sex ratio of foetuses was 1:3 in favour of males. Variability in life history parameters such as age at sexual maturity and first reproduction, pregnancy rates and calving intervals in dugongs is likely to result from spatial and temporal variation in seagrass community composition and biomass. Thus, food quality and availability influence dugong population dynamics. When their seagrass food disappears as a result of episodic disturbance, some dugongs suspend breeding. It is likely that the effects of food supply on life history parameters and hence fecundity in dugongs includes both density dependent and density independent components. The gaps in the age composition of the catch from Mabuiag in 1997-99 together with the low pregnancy rates of animals caught in the Daru market at that time suggest that a seagrass dieback in Torres Strait in the late 1970s had significant effects on dugong recruitment. These links between seagrass food availability and dugong life history parameters have very important implications for management given the dugong's susceptibility to large-scale episodic losses of seagrass. Several findings in this study highlight that a regional approach to management will be required because the potential for episodic or longer-tern over-harvesting can be exacerbated in the event of a combination of: low dugong fecundity as a result of extensive seagrass dieback events such as that reported in the 1970s; movements of dugongs close to hunting communities to feed on intertidal seagrass in response to dieback of deepwater communities exacerbating high hunting pressure; increase in hunting pressure in response to reduction in important sources of income such as the cray fishery. Management coordinated at a regional scale must include the Northern Peninsula Area of Cape York and PNG. Management will need to build on established processes which incorporate Ailan Kast'om (the customary way of life of Torres Strait Islanders) and institutional structures in the Torres Strait region which include the: Torres Sfraif Treafy, Torres Sfraif Fisheries Acf (1984), Native Title and regional Islander initiatives such as MaSTERS (Marine Strategy for Torres Strait). A community-based management approach, which builds on the research processes, and the empirical information obtained in this study, has considerable potential to ensure that the Torres Strait dugong fishery is sustainable. The challenge now is to build on information and trust generated by this project by enabling Islanders to use these results to develop and implement appropriate management plans for their dugong resources.

Distributed throughout the coastal tropical and sub tropical waters of the Indo-west Pacific, the dugong (Dugong dugon) is considered rare over much of its range and listed by the IUCN (1996) as 'vulnerable to extinction'. The largest numbers of dugongs are believed to occur in Australian waters. The main threats to dugong numbers are anthropogenic activities, such as accidental netting, habitat deterioration and Indigenous hunting. The primary objective of this study is to recognise intraspecific genetic subdivision for dugong management. Complementing ecological studies, these findings have immediate and practical relevance to the conservation management of the dugong. Genetic material was sampled from various types of dugong tissue including skin, muscle, bone, and their faeces. Advances upon established sampling approaches for marine mammals include a biopsy system tailored to dugongs and the extraction, amplification and sequencing of dugong DNA from their faeces. Samples from approximately 250 dugongs were collected by carcass salvage, from dugongs hunted by Indigenous peoples, and by remote sampling of free ranging dugongs. Not all the samples collected were analysed, mainly because of low sample quality. From dugong samples collected from Australia (n=92), West Indian Ocean (n=4) and Asia (n=7), three genetic markers were investigated: the cytochrome b gene and control region of mitochondrial DNA (mtDNA), and microsatellites. Cytochrome b proved to contain insufficient variation for an interpopulation comparison, whereas a block of DNA sequence (194 bases), positioned 5' in the control region of mtDNA, was identified as suitable for interpopulation comparison because of its high variation. A substantial foundation for the development of microsatellite markers for future research was established by this study. In addition to recognising a six base repeat located 3' in the control region of mtDNA, five GT-AC imperfect microsatellites were sequenced from a dugong genome library. The application of microsatellites was not developed further than their location and characterisation. The hypervariable region 1 of mtDNA was sequenced for a total of 103 dugongs, as well as in an outgroup, the Florida manatee (Trichechus manatus latirostris). Among the dugong sequences, 39 variable sites and 37 haplotypes (specific DNA sequences) were found. Phylogenetic trees constructed from the mtDNA haplotypes showed three clusters: West Australian, East Australian and Asian. These haplotype clusters suggest that Asian and East Australian dugongs are more closely related to each other than either group is to the West Australian dugongs. Surprisingly, haplotypes of West Indian Ocean dugongs are extremely similar to the haplotypes of dugongs from East Australia despite their large geographical separation. This suggests that the West Indian Ocean and East Australian dugongs shared a more recent ancestor compared to the Asian or West Australian dugongs. The geographical range of the Asian mtDNA haplotypes does not overlap with the Australian haplotypes. The two Australian mtDNA haplotype clusters overlap geographically in the Great Barrier Reef region. The intraspecific genetic partitioning of dugong populations from Australia, Asia, and the West Indian Ocean, can be partly explained in terms of historical geography. The distinction of the two Australian mtDNA haplotype clusters may be attributed to the Torres Strait (land bridge) acting as a periodic barrier to dugong movements during the Pleistocene low sea level phases. It is of particular interest to management that West Australian haplotypes have such a limited spread to the south and east Australian dugong range. Similarly, East Australian haplotypes do not extend north and west along the Australian coast beyond Torres Strait. Considering the dugong's potential for dispersal, the spread of the two Australian haplotype clusters is remarkably limited. Dugongs have a high intraspecific genetic diversity (average nucleotide diversity = 3.425, and haplotypic diversity = 0.766), and a rate of evolution (suggested to be 2% per Myr per lineage for the HVR-l) that is comparable to most land mammals. The suggested low level of female mediated gene flow between neighbouring populations indicates that successful recolonisation of a depleted area may be extremely slow. For conservation management of the Australian dugong, populations should be treated as distinct units with some degree of overlap. To maintain continuity among these populations, and to preserve the existing high intraspecific genetic diversity, management initiatives should be directed at limiting further fragmentation of the dugongs' range.

Indigenous communities worldwide face multiple challenges to maintain their unique cultural identity and value systems. In the natural resource management arena, these challenges include the imposition of western solutions to environmental management and biodiversity protection. This imposition has caused the dispossession or relocation of Indigenous peoples from their lands, a loss of traditional ecological knowledge, social disempowerment and economic inequity. Indigenous peoples are responding to these challenges by asserting their cultural identity, developing cultural re-vitalisation programs, and actively participating in western political processes for ongoing involvement in the environmental and natural resource management domain. Nonetheless, to date, many of these programs are faltering or have failed in their long-term implementation. Using a case study approach, my thesis examines this issue through an examination of Indigenous hunting of threatened species in a protected area. My research is based on the contention that language matters, as it is an enabling tool which reveals the knowledge and power relations in natural resource management. To this end, I compare perspectives held by Indigenous people on the one hand and government Management Agencies on the other, about traditional hunting, planning and the management of Green turtles (Chelonia mydas) and Dugongs (Dugon dugon) in Australia's Great Barrier Reef World Heritage Area (GBRWHA). To compare these perspectives I used a combination of discourse analysis, historical analysis and participant observation to analyse the development, implementation and subsequent failure of the Hope Vale Turtle and Dugong Hunting Management Plan, ‘Guugu Yimmithirr Bama Wii: Ngawiya and Girrbithi. My research yielded four key findings: (i) that significant differences exist between Management Agencies and Hope Vale Community about hunting, planning and management (Management Agency discourse for example prioritised biodiversity protection, while Indigenous discourse was primarily about ensuring cultural survival); (ii) that language in resource management does matter because different linguistic interpretations within such programs have a direct impact on their efficacy (iii) that social justice dimensions must be incorporated within management regimes in order to achieve both cultural survival and biodiversity protection objectives; and (iv) that resource management initiatives can never be divorced from the impact of external events, actors and power regimes. I thus confirm my thesis or argument that the use and understandings of language in resource management reflect power and knowledge relations, which in turn influence and impact upon the effectiveness of natural resource management programs. Through the integration of these findings my thesis concludes with the presentation of a socially just conservation methodology to guide future collaborations between Indigenous peoples and Management Agencies when addressing the ongoing cultural harvest of wildlife (such as Green turtles and Dugongs) in protected areas.

Thesis (Ph.D.) - James Cook University, 2006.
Appendix 2 (p. 444-454) contains the Research Agreement between the author and the Hopevale Community which governs further research or publications arising from the thesis. Typescript (photocopy). Bibliography: leaves 373-441.

Informing marine planning and the management of species at ecosystem-scales is difficult because data are generally lacking at that scale. Collecting empirical information on the distribution and/or abundance of species across broad spatial scales is expensive and logistically difficult. Accurate and efficient monitoring programmes that assess the response of species to management actions often cannot be conducted at ecosystem-scales due to time, expertise and cost constraints. The Great Barrier Reef World Heritage Area (GBRWHA) of Queensland, Australia, is the world’s largest World Heritage Area (approximately 348,000 km2) and second largest marine protected area (MPA). The region supports a variety of habitats and species including coastal seagrasses and globally significant populations of the dugong (Dugong dugon), a threatened marine mammal. Seagrasses, dugongs and their habitats are exposed to multiple anthropogenic threats along much of the 2,300 km coastline of the GBRWHA. Assessing the effectiveness of the current management arrangements for seagrasses and dugongs and informing the design of new regimes is challenging due to the difficulties associated with data collection and monitoring at the scale of the coastal GBRWHA. My thesis goal was to overcome the difficulties associated with informing the management of coastal seagrasses and dugongs in the GBRWHA by using spatial models and risk assessments in geographical information systems (GIS). My objectives were to: (1) develop spatial models of seagrasses and dugongs at the scale of the coastal GBRWHA; and, (2) use these models to estimate the risk to coastal seagrasses and dugongs from their anthropogenic threats. This approach allowed me to compare and rank the threats to identify the most severe risks, and to locate specific sites that require conservation actions. I used spatial information on the distribution of coastal seagrasses and predictor variables along with ecological theory and expert knowledge to inform the design of a Bayesian belief network, and to develop a predictive seagrass habitat model. The Bayesian belief network quantified the relationship (dependencies) between seagrass habitats and eight environmental drivers: relative wave exposure, bathymetry, spatial extent of flood plumes, season, substrate, region, tidal range and sea surface temperature. The outputs of the modelling exercise were probabilistic GIS-surfaces of seagrass habitat suitability for the entire GBRWHA coast in both the wet and dry seasons at a planning unit of 2 km * 2 km. Quantitative information on the relative impact of the anthropogenic threats to coastal seagrasses is incomplete or unavailable, and the cumulative impact of multiple threats is difficult to measure and predict. In the light of this uncertainty, I used expert knowledge to evaluate the relative risk of coastal seagrass habitats to their hazards. Vulnerability scores derived from expert opinion, spatial information on the distribution of threats and the probabilistic GIS-surfaces of seagrass habitat suitability were used to delineate areas of low, medium and high relative risk to coastal seagrass habitats. I found that whilst most planning units in the remote Cape York region of the GBRWHA are classified as low risk, almost two thirds of coastal seagrass habitats along the urban coast are at high or medium risk from multiple anthropogenic activities. Reducing the risk to coastal seagrass habitats in 13 sites identified for conservation action would require: (1) improving the quality of terrestrial water that enters the GBRWHA; (2) mitigating the impacts of urban and port infrastructure development and dredging; and, (3) addressing the hazards of shipping accidents and recreational boat damage. I derived a spatially explicit dugong population model from spatial information on the abundance and distribution of dugongs collected by a 20 year time-series of aerial surveys. Data from the aerial surveys were corrected for differences in sampling intensity and area sampled between surveys prior to the development of the model. I interpolated the corrected data to the spatial extent of the aerial surveys using the geostatistical estimation method of universal kriging. The model estimated the relative density of dugongs across the GBRWHA at the scale of 2 km * 2 km dugong planning units (the same spatial scale as the seagrass habitat model). I classified each dugong planning unit as of low, medium, or high conservation value on the basis of the relative density of dugongs estimated from the model and a frequency analysis. I compared the spatially explicit dugong population model with information on the distribution of commercial gill-netting activities to estimate the risk of dugong bycatch in the GBRWHA. I found that new management arrangements introduced in the GBRWHA in 2004 appreciably reduced the risk of dugong bycatch by reducing the total area where commercial netting is permitted. Restructuring of the industry further reduced the total area where netting is conducted. Netting is currently prohibited in 67% of dugong planning units of high conservation value, a 56% improvement over the former management arrangements. I identified four sites where netting is still conducted in dugong planning units of high and medium conservation value. Conservation actions including area closures or modified fishing practices should be considered for these regions. In addition to commercial gill-netting, dugongs are threatened by Indigenous hunting, trawling, vessel traffic, and poor quality terrestrial runoff. I developed a rapid approach to assess the risk to dugongs from multiple anthropogenic threats in the GBRWHA, and evaluated options to ameliorate that risk. Expert opinion and a Delphi technique were used to identify and rank anthropogenic threats with the potential to adversely impact dugongs and their habitats. I quantified and compared the distribution of these threats with the spatially explicit model of dugong distribution and found that almost all dugong planning units of high (96%) and medium (93%) conservation value in the GBRWHA are at low risk from human activities. Decreasing the risk to dugongs from anthropogenic threats in four sites that I identified for conservation action would require netting or Indigenous hunting to be banned in the remote Cape York region, and the impacts of vessel traffic, terrestrial runoff and commercial netting to be reduced in urban areas. The approach I developed in this thesis was able to overcome the difficulties associated with informing marine planning and management at ecosystem-scales by using spatial models and risk assessments in GIS to: (1) quantify the spatial distribution of species; and, (2) assess the risk to species and identify sites for conservation action. I was able to achieve this outcome in a data-inadequate environment by combining qualitative assessments on the relative impact of multiple anthropogenic threats with spatial models of species and threat distributions. Implementing conservation actions at the sites that I identified for management will provide the greatest positive result for coastal seagrasses and dugongs at the scale of the GBRWHA. Future research should be directed at understanding the constraints and opportunities for management in the region to ensure that effective implementation of conservation actions can be achieved.

Daniel Zeh studied dugong movements and established proof of concept that acoustic technology provides results comparable to satellite/GPS in two dimensional space use and extends to three dimensional space use. He found evidence of behavioural thermoregulation and the existence of a possible dugong movement corridor, extending current knowledge of dugong behavioural ecology.

Knowledge of the behavioural ecology of a species is important for the development of conservation initiatives. With an understanding of how behaviour has evolved under given environmental and phylogenic constraints, it is possible to predict the response of a population to novel circumstances such as anthropogenic disturbance. Little is known about many aspects of the behaviour of dugongs (Dugong dugon). This species is difficult to observe as dugongs are benthic feeders, usually occurring in turbid waters. They tend to be wary of boats or divers and individuals cannot easily be distinguished. As dugongs occur in shallow, coastal waters, they are particularly vulnerable to human impacts; however, these impacts have not previously been quantified through direct observations of dugong behaviour. To overcome the difficulties in observing dugongs, I developed a blimp-cam, which allowed me to video dugongs from a blimp tethered to my research vessel. The use of the blimp-cam was facilitated by selecting Moreton Bay, Queensland, as my study site, where dugongs are readily located in clear, shallow waters. I used this technology to obtain baseline information about dugong behaviour, and investigated the function of the large herds persistently formed by dugongs in Moreton Bay. I then observed the response of dugongs to boats and pingers (acoustic alarms used on fishing nets to reduce marine mammal bycatch) to determine the risk of boat strikes and effects of disturbance from these two sound sources. At a height of 50m the blimp-cam provided an overhead view of dugongs at water depths of up to 4m, and distances of up to 200 m via a monitor on board the research vessel. Using a remote control, I could scan large herds of dugongs or continually observe individuals. Through focal follows of individual dugongs I developed an ethogram and a daily time budget for dugongs in Moreton Bay. Dugongs spent most of their time feeding (41%), travelling (32%), and surfacing (ascending to, and descending from, surface, 18%), and relatively little time resting (7%), socialising (6%) or rolling (1%). Environmental variables accounted for little of the variability in the proportion of time dugongs spent in each behavioural category. Time budgets did not differ significantly between single individuals and mothers with calves. However, mothers spent significantly more time feeding and surfacing, and less time travelling than their calves. Calves were observed suckling for mean bout lengths of 87 s. The mean submergence time for all individuals was 75 s, but was significantly shorter for calves (72 s) in comparison to their mothers (82 s). Submergence times were not affected by depth (< or ≥ 1.5 m), but were affected by behaviour. Dugongs spent 3.5% of the day resting at the surface of the water, during which time they are particularly vulnerable to boat strike. Mother-calf pairs appear most vulnerable to boat strike because they spend more time near the surface than single individuals. Calves are especially vulnerable as they rise or submerge by crossing onto their mother’s back during a quarter of their dives, and spent 13% of their time travelling and resting over their mothers’ back. I found that individual dugongs spent significantly more time feeding while in large, dense herds than when in smaller groups or scattered, suggesting that these herds are formed primarily to facilitate feeding. Dugongs did not seek large herds for resting, and calves were less likely to be surrounded by dugongs other than their mothers, than single individuals. These observations suggest that dugongs do not shelter in herds when most vulnerable to shark attack, and that herds are unlikely to have a predatory defence function. Herd structure was fluid, with individuals changing nearest neighbours after an average of 1 min, and showing no obvious preference for nearest neighbour type (single individual or mother-calf pair). Thus there was no evidence of a social function for these herds. My results support the theory that seagrass distribution and seasonality, sediment type, a lack of other disturbance of seagrass beds, and a yearround presence of dugongs on the Moreton Banks facilitate cultivation grazing. Observations of the response of dugongs to boats passing opportunistically provided information on the risk of boat strikes. Unlike controlled passes which were restricted to the below-planing speed limit of the study area, independent boats were often travelling above this limit. Only boats travelling above planing speed were observed passing directly over the top of dugongs. I hypothesise that the distance of the flight threshold for dugongs remains constant regardless of boat speed. Thus the speed of an approaching boat determines the time dugongs have to evade the boat, and speed is the main factor affecting the risk of boat strikes. Controlled experiments were conducted to determine the effects of boats on dugong behaviour. The behaviour of focal dugongs during a 4.5 min time sample was not significantly affected by whether there was a boat passing, the number of consecutive passes made (1 to 5 passes), or whether the pass was continuous or included a stop and restart during the pass. During the subsurface interval of the focal dugong that corresponded with the control boat’s closest approach time, the travel distance, travel direction and subsurface time were not correlated with the boat’s approach distance. However, during this subsurface interval dugongs were less likely to remain feeding if the boat passed within 50 m than if it passed at a greater distance. Mass movements of dugong feeding herds in response to boats were obvious but only lasted an average of 122 sec. These movements occurred in response to boats passing at all speeds, and at distances of less than 50 m to over 500 m. Relatively low levels of boat traffic in Moreton Bay in winter mean that a maximum 0.8 – 6% of feeding time may be interrupted by boats. However, if the number of boats registered in Queensland continues to increase at the current rate, the rate of disturbance is likely to increase. The response of dugongs to pingers was tested to determine whether these alarms may prevent dugongs from using important habitat areas. An array of two 10kHz ‘BASA’ pingers did not cause an observable response by dugongs. There was no significant difference in the rate of dugong movement away from the focal arena surrounding the pingers, orientation of the dugongs, or the presence or absence of feeding plumes, while the pingers were active compared to when inactive. The observed responses suggest that boat strikes are currently a bigger threat to dugongs than disturbance from boats or pingers, and support speed restrictions for boats in areas commonly used by dugongs. My results also reflect the need for detailed risk assessments to be conducted in areas where dugong habitat overlaps with areas of high boat traffic, and prior to future developments that will increase boat traffic. Further studies that build on the fundamental knowledge of dugong behaviour gained through this research will provide an understanding of human impacts in a wide range of habitats and aid in developing appropriate anthropogenic mortality targets for dugongs.

Knowledge of the behavioural ecology of a species is important for the development of conservation initiatives. With an understanding of how behaviour has evolved under given environmental and phylogenic constraints, it is possible to predict the response of a population to novel circumstances such as anthropogenic disturbance. Little is known about many aspects of the behaviour of dugongs (Dugong dugon). This species is difficult to observe as dugongs are benthic feeders, usually occurring in turbid waters. They tend to be wary of boats or divers and individuals cannot easily be distinguished. As dugongs occur in shallow, coastal waters, they are particularly vulnerable to human impacts; however, these impacts have not previously been quantified through direct observations of dugong behaviour. To overcome the difficulties in observing dugongs, I developed a blimp-cam, which allowed me to video dugongs from a blimp tethered to my research vessel. The use of the blimp-cam was facilitated by selecting Moreton Bay, Queensland, as my study site, where dugongs are readily located in clear, shallow waters. I used this technology to obtain baseline information about dugong behaviour, and investigated the function of the large herds persistently formed by dugongs in Moreton Bay. I then observed the response of dugongs to boats and pingers (acoustic alarms used on fishing nets to reduce marine mammal bycatch) to determine the risk of boat strikes and effects of disturbance from these two sound sources. At a height of 50m the blimp-cam provided an overhead view of dugongs at water depths of up to 4m, and distances of up to 200 m via a monitor on board the research vessel. Using a remote control, I could scan large herds of dugongs or continually observe individuals. Through focal follows of individual dugongs I developed an ethogram and a daily time budget for dugongs in Moreton Bay. Dugongs spent most of their time feeding (41%), travelling (32%), and surfacing (ascending to, and descending from, surface, 18%), and relatively little time resting (7%), socialising (6%) or rolling (1%). Environmental variables accounted for little of the variability in the proportion of time dugongs spent in each behavioural category. Time budgets did not differ significantly between single individuals and mothers with calves. However, mothers spent significantly more time feeding and surfacing, and less time travelling than their calves. Calves were observed suckling for mean bout lengths of 87 s. The mean submergence time for all individuals was 75 s, but was significantly shorter for calves (72 s) in comparison to their mothers (82 s). Submergence times were not affected by depth (< or ≥ 1.5 m), but were affected by behaviour. Dugongs spent 3.5% of the day resting at the surface of the water, during which time they are particularly vulnerable to boat strike. Mother-calf pairs appear most vulnerable to boat strike because they spend more time near the surface than single individuals. Calves are especially vulnerable as they rise or submerge by crossing onto their mother’s back during a quarter of their dives, and spent 13% of their time travelling and resting over their mothers’ back. I found that individual dugongs spent significantly more time feeding while in large, dense herds than when in smaller groups or scattered, suggesting that these herds are formed primarily to facilitate feeding. Dugongs did not seek large herds for resting, and calves were less likely to be surrounded by dugongs other than their mothers, than single individuals. These observations suggest that dugongs do not shelter in herds when most vulnerable to shark attack, and that herds are unlikely to have a predatory defence function. Herd structure was fluid, with individuals changing nearest neighbours after an average of 1 min, and showing no obvious preference for nearest neighbour type (single individual or mother-calf pair). Thus there was no evidence of a social function for these herds. My results support the theory that seagrass distribution and seasonality, sediment type, a lack of other disturbance of seagrass beds, and a yearround presence of dugongs on the Moreton Banks facilitate cultivation grazing. Observations of the response of dugongs to boats passing opportunistically provided information on the risk of boat strikes. Unlike controlled passes which were restricted to the below-planing speed limit of the study area, independent boats were often travelling above this limit. Only boats travelling above planing speed were observed passing directly over the top of dugongs. I hypothesise that the distance of the flight threshold for dugongs remains constant regardless of boat speed. Thus the speed of an approaching boat determines the time dugongs have to evade the boat, and speed is the main factor affecting the risk of boat strikes. Controlled experiments were conducted to determine the effects of boats on dugong behaviour. The behaviour of focal dugongs during a 4.5 min time sample was not significantly affected by whether there was a boat passing, the number of consecutive passes made (1 to 5 passes), or whether the pass was continuous or included a stop and restart during the pass. During the subsurface interval of the focal dugong that corresponded with the control boat’s closest approach time, the travel distance, travel direction and subsurface time were not correlated with the boat’s approach distance. However, during this subsurface interval dugongs were less likely to remain feeding if the boat passed within 50 m than if it passed at a greater distance. Mass movements of dugong feeding herds in response to boats were obvious but only lasted an average of 122 sec. These movements occurred in response to boats passing at all speeds, and at distances of less than 50 m to over 500 m. Relatively low levels of boat traffic in Moreton Bay in winter mean that a maximum 0.8 – 6% of feeding time may be interrupted by boats. However, if the number of boats registered in Queensland continues to increase at the current rate, the rate of disturbance is likely to increase. The response of dugongs to pingers was tested to determine whether these alarms may prevent dugongs from using important habitat areas. An array of two 10kHz ‘BASA’ pingers did not cause an observable response by dugongs. There was no significant difference in the rate of dugong movement away from the focal arena surrounding the pingers, orientation of the dugongs, or the presence or absence of feeding plumes, while the pingers were active compared to when inactive. The observed responses suggest that boat strikes are currently a bigger threat to dugongs than disturbance from boats or pingers, and support speed restrictions for boats in areas commonly used by dugongs. My results also reflect the need for detailed risk assessments to be conducted in areas where dugong habitat overlaps with areas of high boat traffic, and prior to future developments that will increase boat traffic. Further studies that build on the fundamental knowledge of dugong behaviour gained through this research will provide an understanding of human impacts in a wide range of habitats and aid in developing appropriate anthropogenic mortality targets for dugongs.

Comprehensive, up-to-date spatial information on species distributions and threatening processes can enhance the identification of sites for conservation and management action. Such information is often incomplete or simply unavailable at a scale that can inform real-world decision making because the cost and capacity needed for collecting reliable information are high especially when targeting species that occupy large ranges. Obtaining data to inform conservation at the appropriate spatial scale is of particular importance for species that occupy large ranges. The dugong (Dugong dugon) is a seagrass specialist and marine mammal that occurs over 130,000km of coastline in the Indo-West-Pacific. The dugong attracts global conservation attention because it is listed as vulnerable (IUCN Red List) and is increasingly exposed to multiple anthropogenic hazards in most of its range. There are many regions within the dugong's range where the likelihood of survival of the species is unknown. Collecting spatial-ecological information on the dugong in these regions can inform and optimize the effectiveness of regional and national conservation and management initiatives. The island-archipelago of New Caledonia is located in the Oceania region at the eastern edge of the dugong's range. The conservation status of the dugong in this region is unknown. The presence of the charismatic dugong in the lagoons of New Caledonia was an explicit reason for the World Heritage listing of some of the lagoons. No conservation actions have been implemented in New Caledonia to ensure the maintenance of the dugong stock except for the legislation that restricts dugong harvesting despite the species' high biodiversity, cultural and traditional value. The goal of my thesis was to build an evidence-base to enhance the conservation and management of dugongs in New Caledonia at several spatial and temporal scales and enhance understanding of dugong ecology in tropical coral reef environments by: 1. Assessing the temporal changes in the dugong population size and the capacity of the current marine protected areas (MPAs) to protect dugongs at the scale of New Caledonia. 2. Investigating the spatial ecology of dugongs in the coral reef lagoons of New Caledonia by studying their movement patterns and habitat use at local scales. 3. Integrating scientific research conducted on dugongs as part of this thesis to inform decisions relating to dugong conservation and management regionally and internationally. A single baseline aerial survey of dugongs in New Caledonia in 2003 estimated a population of 2026 (± SE = 553) individuals. A second similar survey in 2008 produced a lower estimate of 606 (± SE = 200) individuals, leading to concerns that the dugong population was experiencing a decline. I conducted four additional surveys in 2011 and 2012 with the objectives of updating information on the current size of the dugong population in New Caledonia and investigating evidence of decline in the population. The abundance estimates obtained from my four surveys ranged from 649 (± SE = 195) to 1227 (± SE = 296) dugongs. These results were not significantly different to the 2008 estimate but were significantly lower than the 2003 estimate. I concluded that the confounding effects of variation in environmental conditions, animal behaviour and sampling biases likely played a key role in the variation of the dugong population size estimates as I could not find any evidence external to the surveys that the dugong population had declined between 2003 and 2008 or that temporary migration was likely to have occurred. I used the data obtained from the time series of aerial surveys to develop a spatially-explicit model of dugong distribution and relative density. This model enabled me to determine the distribution of dugongs at the scale of the main island of New Caledonia over nearly a decade of monitoring, and to detect key dugong habitats. Dugongs were not explicitly considered in the design of the network of marine protected areas (MPAs) in New Caledonia. Thus any representation of important dugong areas in the MPA network is incidental. I used the spatially-explicit model of dugong distribution and relative density to retrospectively assess the capacity of the New Caledonia MPA network to protect dugongs from anthropogenic hazards. I quantified the amount of overlap between dugong relative density units and each type of MPA that was managed at the time of the study. I found that most of the important dugong areas in New Caledonia had a low coverage from the MPAs that provide high levels of restriction of anthropogenic activities. I identified several important dugong areas along the west and the north-east coast that were not covered by MPAs and should be considered in future conservation and management plans. The spatial mismatch between MPAs and dugong distribution was likely caused by weaknesses in the planning process. I provided guidance on how these shortcomings can be overcome for marine species of conservation concern in New Caledonia and other regions. The lack of consideration of marine mammals in conservation tools such as MPAs often stems from their highly mobile nature and dynamic movement patterns and the difficulty of defining their specific habitat needs due to lack of knowledge. Information on the dugong's use of space among key habitats and the scale of these movements has been comprehensively studied only in Australian waters where the environment differs from the lagoons of New Caledonia. I used satellite tracking technology to document the use of space by dugongs in the lagoons of New Caledonia. I developed a method of safely and quickly capturing dugongs in coral reef habitats and satellite–tracked 12 adult dugongs in three different regions of the west coast of New Caledonia. Animals displayed individualistic movement patterns. Their extent of movement was large relative to the size of the main island, and some individuals crossed jurisdictional boundaries. Three dugongs exited the lagoon and used the fore reef shelf (i.e., flattened coral reef area, located between the fore reef crest and deep open ocean waters) as corridor to transit from one bay to another. All tracked dugongs returned to their capture location. Home-range analyses showed that the range and core areas used by dugongs reflected the width of the lagoons. The home-range and core areas of dugongs did not differ between day and night. I investigated the habitat use of dugongs at a local scale at Cap Goulvain to enhance understanding of seasonal changes in abundance and habitat use of dugongs in coral reef environments and to provide spatially-explicit data to help local conservation decisions in a key dugong conservation value area. Access to seagrass resources is restricted by tides and the geomorphology of habitats and small size of the lagoon restrict dugongs' space use. I used data obtained from fine-scale dedicated dugong aerial surveys conducted every two weeks over 18 months at low and high tide to determine the seasonal and tidal changes in the number of dugongs and their use of a range of habitats in Cap Goulvain. I then compared the resultant dataset with the temporal changes in water temperature inside and outside the lagoon in this region. I found that more dugongs were sighted during the cool season than during the warm season in Cap Goulvain. At high tide, dugongs were expectedly sighted over the intertidal seagrass meadows in higher proportion than in any other monitored habitats during both seasons. As tides restricted access to the intertidal seagrass meadows there was a seasonal change in the use of other non-seagrass coral reef habitats: during the cool season, a higher proportion of dugongs was sighted outside the lagoon on the fore reef shelf than in any other habitat inside the lagoon; during the warm season the use of the fore reef shelf was less pronounced and dugongs were sighted in higher proportion inside the lagoon in the channels surrounding the intertidal seagrasses. Behavioural thermoregulation is a plausible explanation for the changes in the number of dugongs and the use of the fore reef shelf in Cap Goulvain during the cool season. Further investigation is required to assess the effect of other external factors including the temporal changes in the availability and quality of seagrass and abundance of sharks. Dugong aggregations (i.e., group of ≥ 10 animals) were observed inside the lagoon of Cap Goulvain during the warm season and outside the lagoon during the cool season. I used aerial and underwater footage of the dugong herds located outside the lagoon to explore the behaviour of dugongs in the herds. I found that the dugongs forming the aggregations were resting and no social behaviour other than calves feeding from their mother's teats was identified. The likely causes of dugong aggregations in this habitat include access to warm water, the number of dugongs present in the region at the time, the size of the fore reef shelf, the distance to inshore seagrass resources, and the risk of predation from sharks. These results demonstrated that both seagrass and non-seagrass habitats are important for dugongs and need to be included in future conservation and management programs in New Caledonia as well as other tropical coral reef regions. My thesis provided opportunities to enhance the conservation and management of dugongs in New Caledonia and new insights into the spatial ecology of dugongs in coral reef environments. Future management would be enhanced by considering the important dugong habitats and corridors identified in my research and should be coordinated at an ecological scale relevant to the dugong to be effective. Given the high cultural value of the dugong to the peoples of New Caledonia, communities should be consulted about their desire to participate in community-based management. In addition, ongoing education and communication programs should be continued especially in regions where illegal hunting may occur. Future research should be directed at understanding why illegal hunting occurs in New Caledonia and how compliance with the law could be increased. Further investigating the fine-scale interaction between seagrasses and dugongs in New Caledonia would also greatly enhance our understanding of dugong and seagrass ecology in tropical lagoons and coral reefs more generically.

Dugongs (Dugong dugon) and green turtles (Chelonia mydas) are of international ecological and conservation significance. As one of the few developed countries in their range and with globally significant populations, Australia is in a key position to ensure the survival of both species. Dugongs and green turtles are protected under Australian national and state laws and the rights of Torres Strait Islanders to hunt these species are recognised in Commonwealth and state regulations and an international Treaty between Australia and Papua New Guinea. The Australian government must therefore ensure the sustainable use of these species to comply with biodiversity principles while protecting Indigenous rights. There is thus a potential for conflict, making sound management an absolute imperative. Local stakeholders in Torres Strait have been working together with government agencies to implement co-management arrangements for the Torres Strait Indigenous dugong and green turtle fisheries that acknowledge the ecological and cultural significance of both species. But effective management of the Indigenous fisheries also requires a good understanding of the ecological, economic and social issues operating in Torres Strait and of their interactions. A large body of literature has thus far described the ecological and social systems in the region independently. However, few studies have attempted to describe the synergy between the ecological and social systems. Moreover, economic information about these Torres Strait Indigenous fisheries is all but absent. The overarching objectives of this thesis were thus to provide: (i) economic information, gathered from the point of view of local stakeholders that could be used to inform the management of the Indigenous dugong and green turtle fisheries in the Torres Strait; and (ii) baseline data and insights to underpin subsequent economic investigations. Most of the information required to fulfil those objectives was collected during extended visits (amounting to almost nine months of field work) on two case-study islands: Mabuiag and St Paul's. I used a case study approach to understand the interactions between the ecological system (dugongs and green turtles) and the social system (Torres Strait Islanders) from the point of view of the local stakeholders. I focused on providing economic information that explains at least in part the interactions between the two systems. I used several qualitative and quantitative methods from a range of disciplines to gain this information. The first sub-objective of my research was to improve understanding of the socioeconomic system in which the Torres Strait Indigenous dugong and green turtle fisheries operate. I started by looking at the financial context of those fisheries on my case-study islands using both secondary data (from the Australian Bureau of Statistics) and primary data (collected through household expenditure and shop-price surveys). Through the use of questionnaires complemented by qualitative data collected through semi-structured one-on-one interviews, I also established the size of the harvest of dugongs and green turtles by Mabuiag and St Paul's communities and generated estimates of the market 'value' of the meat, and of the financial (fuel) costs associated with the hunt. I then explored the social processes associated with the Indigenous fisheries, focusing on the way in which the financial costs and benefits were shared. I described the complex distribution of these costs and benefits among several segments of the population within the two communities. I found that groups benefit from hunting through sharing behaviours based primarily on their relationships with hunters and their financial situation. The ways in which meat was shared varied according to whether the hunt was for subsistence or for ceremonial purposes, and hunters reduced their direct financial costs through a complex flow of remittance payments or other indirect contributions. This analysis clearly highlighted the fact that hunters are not the only people closely associated with these fisheries. Evidently, the complex social processes governing the sharing behaviours of traditional marine resources within communities requires a whole community approach rather than a focus on hunters. Having learnt that it was not just hunters who were closely associated with these fisheries, I thus sought to ensure that my subsequent investigations elicited information from a broad range of people within each community on each case-study island. Moreover, the sharing of traditional marine resources was found to extend beyond the boundaries of the Torres Strait communities to members of the Torres Strait Islander Diaspora on the Australian mainland. This information indicates that the scale of management relevant to the Torres Strait Indigenous dugong and green turtle fisheries needs to match the social processes underpinning the sharing of these traditional resources. Initiatives governing the management of those Indigenous fisheries thus need to expand to include members of the Diaspora. The second sub-objective of my thesis was to develop appropriate methods to understand local values associated with the Torres Strait Indigenous dugong and green turtle fisheries (beyond the mere market or financial values considered in the preceding sub-objective). Rather than presenting members of the community with a list of 'values' for consideration, two lists were generated during focus group discussions – one focusing on 'benefits' and one focusing on 'costs'. During individual interviews, respondents were asked to: (a) undertake a cognitive mapping exercise designed to learn more about the relationship between the lists of 'values'; and (b) rate those values. I found that the two communities of Mabuiag and St Paul's identified the same types of benefits and costs and that these costs and benefits could then be categorised into three cognitive clusters. Study participants referred to the benefit clusters as those relating to: community, family and individual benefits. Cost clusters were identified as being those related to the community, the family and the environment. On the 'benefit' side, a clear distinction emerged between the market and non-market benefits; such a distinction was not as clear for costs. The rating exercises highlighted the fact that non-market aspects of the Indigenous fisheries in these two communities were perceived to be more important than market aspects. I also found statistically significant differences in the relative importance ascribed to different costs and benefit clusters by younger and older members of the two communities. Although the relative importance attributed by younger and older members of the two communities was different, both groups considered community benefits and community costs of greatest importance. The clear distinction between the market and non-market benefits enabled me to use a replacement cost method to estimate the financial contribution of the market-related benefits (i.e., those directly linked to food for home consumption) associated with the Indigenous fisheries. My findings indicated that the gross market benefits were worth approximately 8% of household income. My results also suggested that the community benefits (i.e., non-market benefits directly linked to the cultural aspects of the Indigenous fisheries) were statistically more important than the market benefits. As such they must be 'worth' more than 8% of household income. Thus, even without estimating the market value of the individual benefits, I was able to conclude that the gross benefits (market and nonmarket) of the Torres Strait Indigenous dugong and green turtle fisheries exceed 16% of household income (this is approximately equal to the proportion of income spent by the average Australian on mortgage repayments). My third sub-objective was to learn more about the likely social acceptability of different types of fishery management tools. This result was important because the remoteness of Torres Strait and the legal rights of the hunters mean that management tools need to be acceptable to local communities to increase compliance (external monitoring and enforcement is too costly). In a series of individual interviews, I thus asked respondents to evaluate the perceived impacts of several management tools (some of which had already been identified in community management plans) on the different value clusters previously assessed. I argue that a good understanding of these perceptions can provide fisheries managers with an indication for the likely compliance rate of local members towards a specific management tool as well as an indication on its potential social acceptability. I found that tools such as "gear restriction", "seasonal closure" and "spatial closure" were likely to be more acceptable to community members than tools such as "quotas", "taxes" or "subsidies". The methods I used highlighted that the social acceptability of management tools was driven by their perceived impacts on the cultural aspects associated with the Indigenous fisheries. Tools that provided an increase in cultural benefits and a reduction in cultural costs would likely be more accepted than tools that did not. I conclude that policies aiming to connect cultural aspects to the environment may be more likely to succeed than those connecting financial aspects to the environment in these Indigenous fisheries. Finally, the implications of this research for the management of the Indigenous dugong and green turtle fisheries in the Torres Strait and of other traditional natural resource use systems are discussed and suggestions made for future research.

The management of dugongs (Dugong dugon) and green turtles (Chelonia mydas) is a complex social and ecological problem. Dugongs and green turtles are protected by Australian national and sub-national conservation legislation. Both species are important cultural, spiritual and economic (i.e., subsistence) resources for Indigenous Australians. In Australia, Aboriginal and Torres Strait Islander Traditional Owners may hunt these species to satisfy personal, domestic, or non-commercial communal needs. Torres Strait, not only has the largest population of dugongs in the world and one of the largest breeding populations of green turtles, but also has high rates of Indigenous hunting compared to other parts of Australia. Consequently, management of the traditional Torres Strait dugong and green turtle fisheries needs to include social–ecological considerations and involve Torres Strait Island communities. The ecological scales at which dugongs and green turtle operate are large. Dugongs undertake large-scale movements and green turtles undertake breeding migrations, which means the populations that are hunted by Torres Strait Islanders are also hunted or impacted by threats in other countries and in waters off mainland Australia. Thus, management of these populations needs to occur at local, state, national and international scales. To inform the development of management arrangements for the traditional dugong and green turtle fisheries in Torres Strait I aimed to provide an overall context for management at different spatial scales and investigate opportunities and challenges associated with co-management, particularly community-based monitoring. The development of a participatory research process, particularly the research agreement, cultural reference group and employment of Indigenous research counterparts was integral to the study being resilient to external perceptions of hunting reported in the media that threatened to cause hunters to withdraw their participation from the project. Without a process to establish trust, hunters were concerned that the information they provided would be used against them to stop them from hunting. Hence, the process I undertook confirms the importance of strong, resilient co-management partnerships. The risk to dugongs from hunting was evaluated based on spatial data about hunting patterns and dugong distribution and relative abundance. More than 60% (10,690 km²) of the areas supporting very high and high densities of dugongs are at low risk from hunting because hunting is largely restricted to areas close to inhabited islands (i.e., within 30 km). Nevertheless, the areas accessed by hunters also include a substantial amount (6,007 km²) of the very high and high dugong density areas, most of which are the 'sea country' of individual communities. A spatial decision framework based on knowledge of jurisdictional arrangements suggested that different types of management will be appropriate in different parts of the Torres Strait region and that the relative importance of different co-management partners changes with spatial scale. Hunters and elders from Hammond Island were interviewed regarding the need for local management, their perceptions of different management tools and multi-scale co-management from a community perspective. The Hammond Islanders considered some management tools, such as quotas and spatial management, appropriate to incorporate into co-management plans, but that other tools, such as seasonal closures and sex/size-based limits, were inappropriate because of social and cultural factors. Community-based management approaches were considered important especially the application of: (1) cultural norms to the development of tools to achieve compliance and enforcement within the community; and (2) consensus-based decision-making, with regard to the use of more formal rules. The need for cooperation with other communities and stakeholders across spatial scales was also recognised, particularly with regard to enforcement. Overall, the results suggested that co-management is likely to be a more appropriate approach for managing dugongs and green turtles in Torres Strait than either community-based management or government-driven management. Re-analysis of data from two catch-monitoring projects previously conducted in Torres Strait to collect catch statistics and/or life-history parameters on dugongs: (1) occasional sampling and (2) census by an outsider showed that occasional sampling would not provide robust catch-estimates at the individual community level as required for community-based management. I investigated an alternative strategy that considered hunter as the sampling unit. Hunters in the Kaiwalagal communities of Hammond Island and Thursday Island recorded information on datasheets on the number of animals taken, demographic information about the animals taken and information on hunting patterns. Indigenous research counterparts recruited hunters to participate, distributed and collected datasheets, collected biological samples from harvested animals and helped provide feedback to hunters and their communities about the results and progress of the project. The results suggest that a community based approach, such as hunter self-monitoring, will be a more reliable and cost effective approach for determining catch-estimates for dugongs and green turtles to inform co-management at the community level than alternatives such as occasional sampling or census by scientists (e.g., professionally-based monitoring). Hunter self monitoring has fewer limitations and more benefits than the alternatives with respect to: accuracy and precision of the catch estimates, financial costs, trust by communities and capacity to feedback results to communities in a timely manner. Determining the sustainability of the catch requires demographic information about the animals taken as well as the number of animals taken. Hunters recorded information that was more straightforward (e.g., sex) more often than information that was more complex (e.g., reproductive status) and specimens were rarely collected. In addition, hunters did not record unsuccessful trips and therefore an understanding of catch-per-unit-effort could not be obtained. The amount and complexity of information to be collected should ideally be increased in stages as hunters become more proficient, with training in the provision of information at each stage. Collection of information about hunting patterns, including social and cultural considerations, can provide important insight about hunting pressure, which can be useful for guiding decisions regarding the choice and application of management tools. Some of the management options included in the Community Dugong and Turtle Management Plans of other Torres Strait communities, such as stopping spotlighting of green turtles at night, could be effective in reducing catch, but could be difficult to implement. Dugongs and green turtles were caught mostly for general consumption. Therefore, management strategies that limit hunting to ceremonies may be difficult to implement due to the social pressure on hunters, particularly the few prolific hunters who are regularly asked by others to hunt for them. Thus, efforts to change beliefs and behaviours regarding hunting management needs to go beyond hunters to the broader community. Although community-based catch-monitoring will be more appropriate than occasional sampling by professionals to inform co-management of the Torres Strait dugong and green turtle fisheries, there are significant challenges to its implementation. Obtaining insights into the population status and sustainability of the catch will require monitoring temporal trends in a series of indicators using a framework, such as developed in this thesis, to assist in accessing and coordinating the functions necessary to develop and implement a catch-monitoring project. Such a framework could be used by a coordinating organisation such as the Torres Strait Regional Authority to access the necessary technical skills and plan a monitoring project, including highlighting where capacity-building is needed.

The dugong (Dugong dugon) is a coastal marine mammal of conservation concern with a sub-tropical and tropical range extending from East Africa to the Solomon Islands and Vanuatu. Australia is the dugong's stronghold and the site of most modern research. Compared to the research on the dugong's horizontal space use and movement patterns, little is known of the dugong's diving behaviour. Application of behavioural information to large-scale monitoring studies of population abundance has been minimal. My research combined data collected from a variety of technologies and platforms (satellite/GPS wildlife tracking, remote and benthic sensing, aerial survey) to study dugong diving behaviour and improve aerial survey estimates of dugong abundance. The objective of this thesis was to maximise the usage of wildlife tracking data to improve fine-scale knowledge of the dugong diving ecology and to apply this information to improve the methodology to estimate dugong abundance. I achieved these objectives by: 1) developing an empirical procedure to maximise the correct identification of dives recorded by time-depth recorders (TDRs); 2) advancing understanding of fine-scale dugong diving behaviour by linking dive records with fine-scale spatial movement data and habitat descriptions; and 3) improving aerial survey estimates of dugong population size by accounting for their heterogeneous diving and surfacing behaviours. Details of my results follow. Aim 1: Develop an empirical procedure to identify dives in shallow-diving aquatic wildlife such as the dugong Dives from coastal aquatic animals can be difficult to interpret because the shallow nature of their dives relative to the resolution of TDRs often precludes the reliable identification of the different phases of a dive (e.g., descent, bottom, and ascent). I developed an empirical procedure to determine the thresholds for: 1) the zero-offset correction (ZOC) for surface calibration; and 2) the maximum dive depth (dive threshold (DT)). This empirical approach increased the reliability of dive identification and was essential to subsequent interpretations of dugong diving behaviour (Aim 2). Aim 2: Advance insights into fine-scale dugong diving ecology I used statistical models based on dive parameters identified using the methodology developed for Aim 1. Dugongs are benthic feeders that primarily consume seagrass. Thus dugongs reaching in the vicinity of the seafloor where seagrass is present are more likely to be feeding on seagrass than the seafloor where no seagrass is present. However, behavioural inference from dives per se was not attempted because several behaviours can occur over seagrass meadows. Using 8 dive metrics (descent rate, bottom time, vertical displacement, maximum depth, ascent time, ascent rate, asymmetry and ascent rate divided by descent rate), I performed a series of logistic regression models to predict dives that achieved the two criteria: a) mid-water dives that did not provide the dugong with access to the seafloor and dives that did; and b) dives that enabled the dugong to access the seafloor in areas with seagrass and without seagrass. These criteria were determined from a bathymetric model, tidal records, and a seagrass model from shallow banks of Moreton Bay, The logistic regression models showed that compared to dives that had a high likelihood of accessing the seafloor (seafloor dives), dives that had a high likelihood of not reaching the seafloor (mid-water dives) were characterised by shorter bottom times, a larger degree of vertical displacement (presumably the result of active tail movements) during the bottom phase, and slower ascent rates. The profiles of these mid-water dives included U-, V- and other shapes (Fig.1). The dugongs that had a high likelihood of accessing the seafloor in locations supporting seagrass transited quickly between the surface and the seafloor and maximised the time spent on the substratum, presumably maximising nutrient return. The profiles of such dives were mostly classified as square-shaped and less frequently U-shaped. Dugongs undertaking seafloor dives in locations without seagrass also spent a long time on the bottom but were sluggish in all phases of the dive, including the transits between the surface and the bottom. These dives generally had U-shaped profiles (with some square profiles). The dive shapes in the three groups overlapped supporting my assumption that inferences about dive function on a broad classification of dive shapes given the data I examined is not possible. Aim 3: Estimate dugong population size that is more robust by accounting for their heterogeneous diving and surfacing behaviours The current aerial survey methodology used to estimate dugong population sizes at extensive spatial scales accounts for availability bias (animals that are present in survey transects but not visible) due to water turbidity and sea state but assumes constant dugongs' diving and surfacing patterns. To improve availability bias estimates (availability detection probabilities), particularly to account for heterogeneous availability bias, I first estimated availability detection probability by combining data from dugongs fitted with TDRs, GPS satellite tracking units, and fine-scale bathymetric models (Chapter 5). I found availability detection probabilities varied with water depth. All dugongs in clear shallow water (e.g., <1 m) are presumed to be available for detection and the availability bias in these shallow waters was not estimated experimentally. The probability of a dugong being available was next highest in water up to 5 m deep (0.60 to 0.87), followed by water ≥25 m deep (0.58 to 0.85), and lowest in water 5 to 25 m deep (0.34 to 0.69). These depth-specific availability corrections should be more accurate and increasing the likelihood of detecting actual change in a population size. Using correction factors that incorporated the dugong depth-specific availability detection probabilities, I improved estimates of dugong population abundance over three survey regions (Chapter 6). In Moreton Bay, the abundance estimates based on depth-independent (constant) and depth-specific availability detection probabilities were similar because a high proportion of dugongs were sighted in clear shallow water where all animals were potentially available for detection. In Hervey Bay, the abundance estimate based on the depth-specific availability detection probabilities was lower than the estimate using the constant availability detection probabilities, because more than 50% of dugongs were sighted in clear deep water where the estimated depth-specific availability detection probabilities were higher than the depth-independent estimates. In Torres Strait, the difference in the estimated abundance between the two methodologies was large (>3500 dugongs; 28%). Many dugongs were sighted in waters 5-25 m deep in this region and the depth-specific availability estimates were smaller than the estimates independent of water depth, leading to the larger abundance estimate. Summary The results of my research have not only significantly improved understanding of the diving behaviour of dugongs and led to improved estimates of dugong abundance in heterogeneous environments but have also demonstrated methodological advances that should have wider application to shallow-diving aquatic wildlife whose studies are often hampered by coarse resolution of TDRs and affinity of the animals to shallow waters.

Sugar cane production inevitably creates off-site environmental impacts. This thesis addresses the joint production of an agricultural good and environmental externalities and investigates options to manage transboundary effects. Sugar production activities upstream of a marine protected area may alter the natural setting and impose costs on individuals and society that are not offset by commensurate increases in benefits. Expanding the Burdekin River Irrigation Area in North Queensland to supply the Molongle Block would bring areas adjacent to Upstart Bay Dugong Protection Area under cane production with the potential to create net social costs. Irrigated cane production might introduce dry season flows and pollution carried by water, affecting the ecological value of dugong (Dugong dugon) habitat. The thesis examines why environmental damage might occur in the coastal region and explores some of the mechanisms that might be used to better minimise problems. The original contribution is an economic analysis of Dugong Protection Areas, identifying appropriate mechanisms for intervention. A case study of potential cane production adjacent to Upstart Bay is used to explore agricultural pollution mitigation policy options. Constructed wetlands are one option, employing biological processes to mitigate agricultural pollutants. The problem of handling variable loading rates to avoid intertemporal ineffectiveness would lead to high cost mitigation. Controlling the timing of pollutant loadings via retention ponds may be a more cost effective alternative. Retarding dry season flows and first flush events for release in subsequent high flow events is expected to provide reductions in environmental impacts. Subregional retention ponds allow for effective coordination of the timing of wastewater releases and may also have economies of scale advantages. Integrating agricultural production and ecological criteria in economic analysis of policy options revealed shortcomings in available datasets. Gaps in knowledge constrain a full evaluation of mitigation policy, but reflect a situation commonly encountered in natural resource management. Some existing planning tools could be used as a basis for pollution mitigation. The Coastal Protection and Management Act 1995 might be used to strengthen the environmental aspects of land and water management plans required by the Queensland Water Act 2000. Property level drainage outflow points may allow for effective monitoring of water quality. The strategic location of drainage outflow points in a new irrigation development could address measurement problems hindering effective responses. Instruments which might be worthwhile interventions include traditional regulatory approaches and market based instruments. Instruments such as tradeable permits linked to a regional mitigation infrastructure have the potential to further reduce the pollution risk at the lowest social cost. The first challenge in establishing a marketable permit system that creates an incentive to reduce pollution is the setting of limits for the aggregate quantity of pollution permissible. In considering the potential implications of the case study for the sugar growing industry as a whole, more parameters become relevant for policy analysis. A whole of catchment approach similar to the Productivity Commission investigation of policy options for water quality and the Great Barrier Reef lagoon (2003) provides a framework to address complex land use issues affecting the land-marine interface. It is argued that policy options that inherently create incentives to reveal private information aligning private interests with desired environmental outcomes and allow for site variability must feature as part of the abatement policy mix. Finding ways to lever community capacity to implement policy options and ensure desired environmental outcomes through adopting some targeted regulatory options remains the challenge for agricultural pollution mitigation policy.

Sugar cane production inevitably creates off-site environmental impacts. This thesis addresses the joint production of an agricultural good and environmental externalities and investigates options to manage transboundary effects. Sugar production activities upstream of a marine protected area may alter the natural setting and impose costs on individuals and society that are not offset by commensurate increases in benefits. Expanding the Burdekin River Irrigation Area in North Queensland to supply the Molongle Block would bring areas adjacent to Upstart Bay Dugong Protection Area under cane production with the potential to create net social costs. Irrigated cane production might introduce dry season flows and pollution carried by water, affecting the ecological value of dugong (Dugong dugon) habitat. The thesis examines why environmental damage might occur in the coastal region and explores some of the mechanisms that might be used to better minimise problems. The original contribution is an economic analysis of Dugong Protection Areas, identifying appropriate mechanisms for intervention. A case study of potential cane production adjacent to Upstart Bay is used to explore agricultural pollution mitigation policy options. Constructed wetlands are one option, employing biological processes to mitigate agricultural pollutants. The problem of handling variable loading rates to avoid intertemporal ineffectiveness would lead to high cost mitigation. Controlling the timing of pollutant loadings via retention ponds may be a more cost effective alternative. Retarding dry season flows and first flush events for release in subsequent high flow events is expected to provide reductions in environmental impacts. Subregional retention ponds allow for effective coordination of the timing of wastewater releases and may also have economies of scale advantages. Integrating agricultural production and ecological criteria in economic analysis of policy options revealed shortcomings in available datasets. Gaps in knowledge constrain a full evaluation of mitigation policy, but reflect a situation commonly encountered in natural resource management. Some existing planning tools could be used as a basis for pollution mitigation. The Coastal Protection and Management Act 1995 might be used to strengthen the environmental aspects of land and water management plans required by the Queensland Water Act 2000. Property level drainage outflow points may allow for effective monitoring of water quality. The strategic location of drainage outflow points in a new irrigation development could address measurement problems hindering effective responses. Instruments which might be worthwhile interventions include traditional regulatory approaches and market based instruments. Instruments such as tradeable permits linked to a regional mitigation infrastructure have the potential to further reduce the pollution risk at the lowest social cost. The first challenge in establishing a marketable permit system that creates an incentive to reduce pollution is the setting of limits for the aggregate quantity of pollution permissible. In considering the potential implications of the case study for the sugar growing industry as a whole, more parameters become relevant for policy analysis. A whole of catchment approach similar to the Productivity Commission investigation of policy options for water quality and the Great Barrier Reef lagoon (2003) provides a framework to address complex land use issues affecting the land-marine interface. It is argued that policy options that inherently create incentives to reveal private information aligning private interests with desired environmental outcomes and allow for site variability must feature as part of the abatement policy mix. Finding ways to lever community capacity to implement policy options and ensure desired environmental outcomes through adopting some targeted regulatory options remains the challenge for agricultural pollution mitigation policy.

The Labour Intensive Public Work (LIPW) programme under the Ghana Social Opportunity Project (GSOP), is a social protection programme initiated by the Government of Ghana, to offer jobs and income earning opportunities to some targeted rural residents, especially the youth, through the application of labour intensive technology in the construction of community infrastructure that has the potential of generating secondary employment. This is a mixed method study sought to provide an account on the Ghanian version of LIPW programmes. The study assessed and identified the challenges facing the programme implementation from beneficiary and implementers’ perspective in order to set the platform for an interactive feedback between project implementers and community members for the smooth implementation of future LIPW programmes. The study also assessed the impact of the programme on poverty and migration among the youth in Ghana. In identifying the challenges facing the programme from implementers’ perspective, 15 key project implementers were interviewed. An interview guide and a questionnaire were also developed to collect data from 500 beneficiaries of the programme to know their challenges. In assessing the impact of the programme on migration among the youth, questionnaires were administered to 239 households in beneficiary communities and 189 households from non-beneficiary communities of the LIPW programme. Finally, data was collected from 90 youth who benefited from the programme and 90 youth who did not benefit from the programme to compare and determine the extent to which the programme has contributed in reducing poverty among the youth. The study revealed that the key challenge facing the programme implementation from the implementers’ perspective is capacity problem involving, inadequacy of staff to implement the programme at the district level, frequent breakdown of vehicles for monitoring, and delays in the release of funds for commencement of project. Beneficiaries of the programme also indicated that they were not satisfied with the amount of money they were receiving as wage for their labour. They were also unhappy with the delays in payment of their wages and the period of engagement in the programme. The study found out that the LIPW programme under the GSOP has not contributed in reducing migration among the youth. However, the programme has contributed to reducing poverty among the youth. The study therefore recommends that capacity gap analysis conducted before project initiation should include adequacy of staff and logistics to cater for any deficiency. It is strongly recommended that beneficiaries of the programme should be consulted in setting the wage rate to avoid resentment provoking misunderstanding between beneficiaries and project implementers. The study further recommended that the government should scale up the programme to cover more communities in order to reduce poverty among the youth in Ghana. Finally, the study proposed a new model for LIPW for the youth known as ‘LIPW +3Cs’. This model incorporates three Cs, that is ‘C’ompetence’, ‘C’onnections’ and ‘C’haracter’ into LIPW programmes. ‘LIPW +3Cs’ will not only train youth to secure jobs after the programme (Competence) but will assist them to establish a network among themselves and other supporting institutions (Connections). Issues of character which encompases a sense of right and wrong will also be inculcated in the youth to assist them to function effectively in the society (Character).
Adult Basic Education (ABET)
D. Phil. (Adult Education and Youth Development)