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Artykuły w czasopismach na temat "Estuarine habitats"
1
Bissoli, Lorena B., i Angelo F. Bernardino. "Benthic macrofaunal structure and secondary production in tropical estuaries on the Eastern Marine Ecoregion of Brazil". PeerJ 6 (28.02.2018): e4441. http://dx.doi.org/10.7717/peerj.4441.
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Tropical estuaries are highly productive and support diverse benthic assemblages within mangroves and tidal flats habitats. Determining differences and similarities of benthic assemblages within estuarine habitats and between regional ecosystems may provide scientific support for management of those ecosystems. Here we studied three tropical estuaries in the Eastern Marine Ecoregion of Brazil to assess the spatial variability of benthic assemblages from vegetated (mangroves) and unvegetated (tidal flats) habitats. A nested sampling design was used to determine spatial scales of variability in benthic macrofaunal density, biomass and secondary production. Habitat differences in benthic assemblage composition were evident, with mangrove forests being dominated by annelids (Oligochaeta and Capitellidae) whereas peracarid crustaceans were also abundant on tidal flats. Macrofaunal biomass, density and secondary production also differed between habitats and among estuaries. Those differences were related both to the composition of benthic assemblages and to random spatial variability, underscoring the importance of hierarchical sampling in estuarine ecological studies. Given variable levels of human impacts and predicted climate change effects on tropical estuarine assemblages in Eastern Brazil, our data support the use of benthic secondary production to address long-term changes and improved management of estuaries in Eastern Brazil.
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Henderson, Christopher J., Ben L. Gilby, Thomas A. Schlacher, Rod M. Connolly, Marcus Sheaves, Nicole Flint, Hayden P. Borland i Andrew D. Olds. "Contrasting effects of mangroves and armoured shorelines on fish assemblages in tropical estuarine seascapes". ICES Journal of Marine Science 76, nr 4 (4.02.2019): 1052–61. http://dx.doi.org/10.1093/icesjms/fsz007.
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Abstract Coastal seascapes are composed of a diversity of habitats that are linked in space and time by the movement of organisms. The context and configuration of coastal ecosystems shapes many important properties of animal assemblages, but potential seascape effects of natural and artificial habitats on nearby habitats are typically considered in isolation. We test whether, and how, the seascape context of natural and urban habitats modified fish assemblages across estuaries. Fish were sampled with underwater videos in five habitat types (mangroves, rock bars, log snags, unvegetated sediments, armoured shorelines) in 17 estuaries in eastern Australia. Different habitats supported distinct fish assemblages, but the spatial context of mangroves and armoured shorelines had pervasive ecological effects that extended across entire estuaries. In most estuarine habitats, fish diversity and abundance was greatest when they were in close proximity of mangroves, and decreased due to the proximity of armoured shorelines. Many cities are centred on estuaries, and urban expansion is often associated with the fragmentation of mangrove forests. Our findings emphasize that these transformations of urban estuarine landscapes are likely to propagate to broader ecological impacts detectable in multiple habitats beyond mangrove forests.
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Murray, Taryn S., Paul D. Cowley, Rhett H. Bennett i Amber-Robyn Childs. "Fish on the move: connectivity of an estuary-dependent fishery species evaluated using a large-scale acoustic telemetry array". Canadian Journal of Fisheries and Aquatic Sciences 75, nr 11 (listopad 2018): 2038–52. http://dx.doi.org/10.1139/cjfas-2017-0361.
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Connectivity — movements of animals between and among numerous habitats — and the factors (rhythmic cycles and environmental variables) influencing connectivity of juvenile Lichia amia (Teleostei: Carangidae) were assessed in complementary acoustic telemetry studies in two geographically separated estuaries (620 km apart) in South Africa. The studies were conducted within a nationwide array of acoustic receivers moored in estuaries and coastal waters. Tagged fish in both the Kowie (n = 21) and Goukou (n = 17) estuaries displayed high levels of multiple habitat connectivity, with 81% and 76% visiting nearby marine and estuarine environments, respectively. The presence of tagged L. amia within the tagging estuaries was significantly influenced by river and sea temperature (Kowie) and river inflow and moon phase (Goukou). Tidal phase, time of day, and season were found to significantly influence marine excursions undertaken by Kowie- and Goukou-tagged fish. Our study provides an assessment of connectivity among multiple estuarine, port, and marine habitats, relating those movements to rhythmic cycles and environmental variables, and highlights the benefits of tracking animals using an extensive acoustic receiver array that spans multiple habitats.
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Pita, Ana Laura, Luis Giménez, Noelia Kandratavicius, Pablo Muniz i Natalia Venturini. "Benthic trophic status of aquatic transitional environments with distinct morphological and dynamic characteristics on the south-western Atlantic coast". Marine and Freshwater Research 68, nr 11 (2017): 2028. http://dx.doi.org/10.1071/mf16284.
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The benthic trophic status of Uruguayan coastal estuarine habitats (permanently open estuaries and open or closed coastal lagoons) was evaluated, twice in 1 year and at different spatial scales, using the amount and biochemical composition of the sedimentary organic matter. Nested hierarchical ANOVAs were applied to evaluate differences at the habitat level, among sites for each type of estuarine habitat (three estuaries and three lagoons) and between sectors located at different distances from the sea (inner v. outer sectors). Morphological and hydrodynamic differences between the two types of habitats explained site-to-site variations in eutrophic conditions in the open or closed coastal lagoons and meso-oligotrophic conditions in permanently open estuaries. These differences followed the patterns found for sediment grain size, with inner sectors (lower-energy areas) favouring the accumulation of finer sediments and higher amounts of degraded–detrital organic matter. In autumn, biochemical parameters indicated the dominance of aged and more degraded organic matter, with both types of habitats having a low nutritional value no matter which sector was considered. By contrast, in spring, biochemical composition showed the prevalence of fresh and more labile sedimentary organic matter with a high food value, especially in the outer sectors.
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Taylor, Matthew D. "Spatial and temporal patterns of habitat use by three estuarine species of mysid shrimp". Marine and Freshwater Research 59, nr 9 (2008): 792. http://dx.doi.org/10.1071/mf07247.
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The mysids Rhopalopthalmus egregius, Haplostylus dakini and Doxomysis australiensis are abundant yet unstudied omnivorous crustaceans in Australian estuaries. Habitat use and population dynamics were investigated for these species over spring and summer in the Tweed River, Australia, to explore their ecological role in estuarine ecosystems. Overall, mysids were concentrated in shallow unvegetated and deep unvegetated estuarine habitats. H. dakini were most abundant in shallow and deep bare habitats at night, whereas R. egregius were most abundant in deep bare habitats during the night. D. australiensis were present across all habitats in the night, but negligible numbers were present during the day. Significantly greater numbers of R. egregius and D. australiensis were sampled during the new moon, compared with the full moon. Significantly larger R. egregius and D. australiensis individuals were present in benthic habitats at night, indicating possible partitioning of habitat for juvenile and adult subpopulations. Adaptive foraging strategies and habitat use facilitates the coexistence of sympatric mysid species, H. dakini and R. egregius, and within-species habitat partitioning allowed juvenile R. egregius to avoid interaction with adult R. egregius. The observed dynamics minimize inter- and intra-specific predation between mysids, and by other predators, while optimizing access to key trophic resources.
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Hughes, Brent B., Kerstin Wasson, M. Tim Tinker, Susan L. Williams, Lilian P. Carswell, Katharyn E. Boyer, Michael W. Beck i in. "Species recovery and recolonization of past habitats: lessons for science and conservation from sea otters in estuaries". PeerJ 7 (10.12.2019): e8100. http://dx.doi.org/10.7717/peerj.8100.
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Recovering species are often limited to much smaller areas than they historically occupied. Conservation planning for the recovering species is often based on this limited range, which may simply be an artifact of where the surviving population persisted. Southern sea otters (Enhydra lutris nereis) were hunted nearly to extinction but recovered from a small remnant population on a remote stretch of the California outer coast, where most of their recovery has occurred. However, studies of recently-recolonized estuaries have revealed that estuaries can provide southern sea otters with high quality habitats featuring shallow waters, high production and ample food, limited predators, and protected haul-out opportunities. Moreover, sea otters can have strong effects on estuarine ecosystems, fostering seagrass resilience through their consumption of invertebrate prey. Using a combination of literature reviews, population modeling, and prey surveys we explored the former estuarine habitats outside the current southern sea otter range to determine if these estuarine habitats can support healthy sea otter populations. We found the majority of studies and conservation efforts have focused on populations in exposed, rocky coastal habitats. Yet historical evidence indicates that sea otters were also formerly ubiquitous in estuaries. Our habitat-specific population growth model for California’s largest estuary—San Francisco Bay—determined that it alone can support about 6,600 sea otters, more than double the 2018 California population. Prey surveys in estuaries currently with (Elkhorn Slough and Morro Bay) and without (San Francisco Bay and Drakes Estero) sea otters indicated that the availability of prey, especially crabs, is sufficient to support healthy sea otter populations. Combining historical evidence with our results, we show that conservation practitioners could consider former estuarine habitats as targets for sea otter and ecosystem restoration. This study reveals the importance of understanding how recovering species interact with all the ecosystems they historically occupied, both for improved conservation of the recovering species and for successful restoration of ecosystem functions and processes.
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Bernardino, Angelo Fraga, Paulo Roberto Pagliosa, Ronaldo Adriano Christofoletti, Francisco Barros, Sergio A. Netto, Pablo Muniz i Paulo da Cunha Lana. "Benthic estuarine communities in Brazil: moving forward to long term studies to assess climate change impacts". Brazilian Journal of Oceanography 64, spe2 (2016): 81–96. http://dx.doi.org/10.1590/s1679-875920160849064sp2.
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Abstract Estuaries are unique coastal ecosystems that sustain and provide essential ecological services for mankind. Estuarine ecosystems include a variety of habitats with their own sediment-fauna dynamics, all of them globally undergoing alteration or threatened by human activities. Mangrove forests, saltmarshes, tidal flats and other confined estuarine systems are under increasing stress due to human activities leading to habitat and species loss. Combined changes in estuarine hydromorphology and in climate pose severe threats to estuarine ecosystems on a global scale. The ReBentos network is the first integrated attempt in Brazil to monitor estuarine changes in the long term to detect and assess the effects of global warming. This paper is an initial effort of ReBentos to review current knowledge on benthic estuarine ecology in Brazil. We herein present and synthesize all published work on Brazilian estuaries that has focused on the description of benthic communities and related ecological processes. We then use current data on Brazilian estuaries and present recommendations for future studies to address climate change effects, suggesting trends for possible future research and stressing the need for long-term datasets and international partnerships.
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Whitfield, AK. "Littoral habitats as major nursery areas for fish species in estuaries: a reinforcement of the reduced predation paradigm". Marine Ecology Progress Series 649 (10.09.2020): 219–34. http://dx.doi.org/10.3354/meps13459.
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For many decades, the role of estuaries as important nursery areas for fishes was accepted as fact by scientists and environmental managers. At the turn of the 21st century, a question mark was raised in relation to the reduced predation component of the nursery function, with some scientists contending that both large and small piscivorous fish species had access to the estuarine habitats that juvenile fishes in estuaries occupied. If true on a global scale, the nursery designation for these habitats would be compromised and the long-held paradigm that estuaries are important nursery areas for fishes would need to be revised. In this review, I examine the nature of fish nursery areas in estuarine littoral habitats from a mainly predation perspective and, based on a variety of ichthyofaunal and avifaunal studies, come to the conclusion that apart from a few selected estuarine systems, there is limited predation on juvenile fishes in these particular areas. This, coupled with the abundant suitable food resources for juvenile fish from different trophic categories, shelter from high-energy marine wave action and biological connectivity between a variety of submerged and emergent macrophyte communities, renders shallow estuarine littoral areas ideal nursery areas for the juveniles of mostly euryhaline marine fish species, the dominant component of estuarine ichthyofaunas globally. In addition, there are strong indications from the fossil record that these littoral estuarine nursery areas have been functioning since the Devonian, more than 350 million years ago.
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Werry, J. M., S. Y. Lee, N. M. Otway, Y. Hu i W. Sumpton. "A multi-faceted approach for quantifying the estuarine - nearshore transition in the life cycle of the bull shark, Carcharhinus leucas". Marine and Freshwater Research 62, nr 12 (2011): 1421. http://dx.doi.org/10.1071/mf11136.
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Understanding the ontogenetic habitat linkages of sharks is important for conservation and managing human interactions. We used acoustic telemetry, catch data, elemental and stable isotope signatures and dietary analyses to investigate ontogenetic habitat use in south-east Queensland, Australia, by the bull shark Carcharhinus leucas, a IUCN ‘near-threatened’ species that is implicated in many shark attacks on humans in urban estuaries. Sequential analyses for δ15N and δ13C of vertebrae from five adult C. leucas and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) for elemental composition from 23 C. leucas, including a pregnant female, were also used to trace ontogenetic habitat dependence. Acoustic telemetry indicated large juvenile and subadult C. leucas remained in estuarine habitats. δ15N values across shark vertebrae showed an ontogenetic shift in diet with total length (TL), confirmed by stomach contents. LA-ICPMS data reflected the ontogenetic movements of C. leucas from natal habitats. Differences among adults were gender related. Shifts in habitat use by subadults were correlated with a sigmoidal δ13C relationship with TL. C. leucas have a multipartite, stage-specific dependency in their transition between habitats along the freshwater–estuarine–marine continuum, making them particularly susceptible to the habitat alteration that is occurring globally.
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Meynecke, J. O. "Coastal habitat connectivity ? implications for declared fish habitat networks in Queensland, Australia". Pacific Conservation Biology 15, nr 2 (2009): 96. http://dx.doi.org/10.1071/pc090096.
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Estuaries are widely recognized as key habitats supporting nearshore secondary production and catch of commercial fisheries. In Queensland, some of these coastal marine habitats are protected by the declared fish habitat programme run by the Department of Primary Industries and Fisheries. Expected environmental changes for Australian estuarine systems include reduced freshwater flow, increased sedimentation and with them, a loss of connectivity. At present, the relationship between the protected declared fish habitat and habitat connectivity remains unknown. By comparing long term coastal fish catch data with geomorphic characteristics of coastal habitats structural connectivity was previously identified as a potential driver of commercial fish catch in Queensland. An ecology landscape approach was used for this study to identify potential fish habitat hotspots along the coastline of Queensland thus allowing better defined networks of declared fish habitats. A comparison between this approach and the current declared fish habitats demonstrated potential deficits and provided important insights for fisheries management. Declared fish habitats should be placed in coastal habitats with high structural connectivity to ensure sustainability of fisheries in light of environmental changes.
Rozprawy doktorskie na temat "Estuarine habitats"
1
Guest, Michaela A., i n/a. "Movement and Assimilation of Carbon by Estuarine Invertebrates". Griffith University. School of Environmental and Applied Science, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20061024.110617.
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In estuarine and other aquatic systems, it is possible for water to transport locally produced carbon (food) across habitat boundaries, and provide nutrition for animals remote from the carbon source. In estuarine and marine systems, early work examining the movement of carbon from saltmarsh habitats in the USA suggested that carbon may move large distances from inshore to offshore environments. Upon closer examination, however, evidence did not support this paradigm of large-scale carbon movement, referred to as the outwelling hypothesis, in some estuaries. Physical characteristics of estuaries in which large-scale carbon movement did not occur, such as restricted access to the sea, were proposed as a possible explanation, and for these estuaries, movement of carbon among estuarine habitats was considered more likely. A mosaic of saltmarsh and mangrove habitats dominate the subtropical barrier estuary of southern Moreton Bay, Queensland, but there have been no studies that examine the movement of carbon among habitats within this system. Previous studies that examine the movement of carbon have mostly been done in saltmarshes in the northern hemisphere or in tropical mangrove systems. Different vegetation and tidal regimes in temperate marshes of the northern hemisphere preclude generalisations of carbon movement to tropical and subtropical systems. Our understanding of carbon movement in tropical systems may extend to subtropical waters, but the saltmarsh-mangrove mosaic in the subtropics distinguishes them from their tropical counterparts. The mosaic of saltmarsh and mangrove habitats among the barrier islands of southern Moreton Bay thus provide a unique opportunity to examine the small-scale movement of carbon among adjacent habitats in a subtropical system. Stable isotopes of carbon have been used successfully to trace the transfer of carbon from autotrophs to consumers at a range of spatial scales. This method is able to distinguish among carbon sources where autotrophs have different ratios of 13C/12C, and consumers take on the ratio of their food source. The success of stable isotopes in clarifying food web processes, however, depends on isotope ratios changing in predictable ways as elements are processed. As isotope ratios may be influenced by changes in productivity, and differences in nutrient source, they may vary across small and large spatial scales that may confound interpretation of food web processes. In this study I measured small and large-scale spatial variability of three estuarine autotrophs (the saltmarsh grass, Sporobolus virginicus, the seagrass Zostera capricorni and the algal community epiphytic on Z. capricorni) and showed the small-scale spatial variability to be negligible and insufficient to preclude the use of carbon and nitrogen isotopes in food web studies. Large-scale variability was more pronounced and may be useful for spatial correlation of food webs for more mobile species. The small-scale homogeneity and clearly distinguished isotope ratios of the dominant autotrophs in adjacent saltmarsh and mangrove habitats in southeast Queensland are therefore ideally suited to the study of small-scale carbon movement between adjacent habitats. Carbon isotopes of estuarine invertebrates were used to estimate the movement of particulate carbon between adjacent saltmarsh and mangroves at the tens-of-metre scale. Carbon isotope values of two crab species (Parasesarma erythrodactyla and Australoplax tridentata) and two snail species (Salinator solida and Ophicardelus quoyi) in saltmarsh closely match those of the saltmarsh grass, and suggest that the movement and assimilation of carbon occurs at a scale much smaller than has previously been examined. In mangroves, the results of this study indicate that microphytobenthos with some contribution of mangrove carbon is the most likely food source for P. erythrodactyla and A. tridentata, although contribution of carbon from saltmarsh is also possible. Under this latter scenario, carbon movement in mangroves would be considered to occur at a scale larger than that in saltmarsh habitat. A study that examined the movement and assimilation of carbon by crabs and an estuarine slug (Onchidina australis) at a finer resolution (i.e. metres) supported the original findings and indicated that the movement and assimilation of carbon occurs 5 - 8 m either side of the saltmarsh-mangrove interface. At this small-scale, the movement and subsequent foraging of crabs among habitats, the movement of particulate carbon among habitats, or a combination of crab and particulate carbon movement are three alternative models that provide plausible explanations for the pattern in carbon isotope values of crabs. Crab movement among these habitats was measured using an array of pitfall traps perpendicular to the saltmarsh-mangrove interface. To test for carbon movement, samples of detritus were collected at 2 m intervals across this same interface and the carbon isotopes analysed. For the majority of crabs (up to 90% for both species), movement up or down the shore was less than 1 m from the place of initial capture. Thus, crab movement cannot explain the trend in carbon isotope values of crabs. The pattern in detrital isotope values was similar to that of crabs and indicates that the movement of particulate carbon across the saltmarsh-mangrove interface is the most likely explanation for crab isotope ratios. Sources of carbon for estuarine invertebrates can also depend on the size of the saltmarsh patches. Examination of the movement and assimilation of carbon by crabs in saltmarsh patches of different sizes adjacent to mangroves indicates that saltmarshes less than 0.3 ha in area are subsidised by the import of allochthonous carbon, most likely from mangroves. These findings contribute substantially to our understanding of the food web value of estuarine habitats and provide an important link between landscape and food web ecology. They also have important implications for determining the conservation value of estuarine habitats with respect to their functional (food web) value. The scale-dependent sampling used in this thesis also provides important evidence for the fine-scale movement of estuarine carbon that has not previously been examined.
2
Guest, Michaela A. "Movement and Assimilation of Carbon by Estuarine Invertebrates". Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367539.
Pełny tekst źródłaStreszczenie:
In estuarine and other aquatic systems, it is possible for water to transport locally produced carbon (food) across habitat boundaries, and provide nutrition for animals remote from the carbon source. In estuarine and marine systems, early work examining the movement of carbon from saltmarsh habitats in the USA suggested that carbon may move large distances from inshore to offshore environments. Upon closer examination, however, evidence did not support this paradigm of large-scale carbon movement, referred to as the outwelling hypothesis, in some estuaries. Physical characteristics of estuaries in which large-scale carbon movement did not occur, such as restricted access to the sea, were proposed as a possible explanation, and for these estuaries, movement of carbon among estuarine habitats was considered more likely. A mosaic of saltmarsh and mangrove habitats dominate the subtropical barrier estuary of southern Moreton Bay, Queensland, but there have been no studies that examine the movement of carbon among habitats within this system. Previous studies that examine the movement of carbon have mostly been done in saltmarshes in the northern hemisphere or in tropical mangrove systems. Different vegetation and tidal regimes in temperate marshes of the northern hemisphere preclude generalisations of carbon movement to tropical and subtropical systems. Our understanding of carbon movement in tropical systems may extend to subtropical waters, but the saltmarsh-mangrove mosaic in the subtropics distinguishes them from their tropical counterparts. The mosaic of saltmarsh and mangrove habitats among the barrier islands of southern Moreton Bay thus provide a unique opportunity to examine the small-scale movement of carbon among adjacent habitats in a subtropical system. Stable isotopes of carbon have been used successfully to trace the transfer of carbon from autotrophs to consumers at a range of spatial scales. This method is able to distinguish among carbon sources where autotrophs have different ratios of 13C/12C, and consumers take on the ratio of their food source. The success of stable isotopes in clarifying food web processes, however, depends on isotope ratios changing in predictable ways as elements are processed. As isotope ratios may be influenced by changes in productivity, and differences in nutrient source, they may vary across small and large spatial scales that may confound interpretation of food web processes. In this study I measured small and large-scale spatial variability of three estuarine autotrophs (the saltmarsh grass, Sporobolus virginicus, the seagrass Zostera capricorni and the algal community epiphytic on Z. capricorni) and showed the small-scale spatial variability to be negligible and insufficient to preclude the use of carbon and nitrogen isotopes in food web studies. Large-scale variability was more pronounced and may be useful for spatial correlation of food webs for more mobile species. The small-scale homogeneity and clearly distinguished isotope ratios of the dominant autotrophs in adjacent saltmarsh and mangrove habitats in southeast Queensland are therefore ideally suited to the study of small-scale carbon movement between adjacent habitats. Carbon isotopes of estuarine invertebrates were used to estimate the movement of particulate carbon between adjacent saltmarsh and mangroves at the tens-of-metre scale. Carbon isotope values of two crab species (Parasesarma erythrodactyla and Australoplax tridentata) and two snail species (Salinator solida and Ophicardelus quoyi) in saltmarsh closely match those of the saltmarsh grass, and suggest that the movement and assimilation of carbon occurs at a scale much smaller than has previously been examined. In mangroves, the results of this study indicate that microphytobenthos with some contribution of mangrove carbon is the most likely food source for P. erythrodactyla and A. tridentata, although contribution of carbon from saltmarsh is also possible. Under this latter scenario, carbon movement in mangroves would be considered to occur at a scale larger than that in saltmarsh habitat. A study that examined the movement and assimilation of carbon by crabs and an estuarine slug (Onchidina australis) at a finer resolution (i.e. metres) supported the original findings and indicated that the movement and assimilation of carbon occurs 5 - 8 m either side of the saltmarsh-mangrove interface. At this small-scale, the movement and subsequent foraging of crabs among habitats, the movement of particulate carbon among habitats, or a combination of crab and particulate carbon movement are three alternative models that provide plausible explanations for the pattern in carbon isotope values of crabs. Crab movement among these habitats was measured using an array of pitfall traps perpendicular to the saltmarsh-mangrove interface. To test for carbon movement, samples of detritus were collected at 2 m intervals across this same interface and the carbon isotopes analysed. For the majority of crabs (up to 90% for both species), movement up or down the shore was less than 1 m from the place of initial capture. Thus, crab movement cannot explain the trend in carbon isotope values of crabs. The pattern in detrital isotope values was similar to that of crabs and indicates that the movement of particulate carbon across the saltmarsh-mangrove interface is the most likely explanation for crab isotope ratios. Sources of carbon for estuarine invertebrates can also depend on the size of the saltmarsh patches. Examination of the movement and assimilation of carbon by crabs in saltmarsh patches of different sizes adjacent to mangroves indicates that saltmarshes less than 0.3 ha in area are subsidised by the import of allochthonous carbon, most likely from mangroves. These findings contribute substantially to our understanding of the food web value of estuarine habitats and provide an important link between landscape and food web ecology. They also have important implications for determining the conservation value of estuarine habitats with respect to their functional (food web) value. The scale-dependent sampling used in this thesis also provides important evidence for the fine-scale movement of estuarine carbon that has not previously been examined.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental and Applied Science
Full Text
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Melville, Andrew J., i n/a. "Stable Isotope Tests of the Trophic Role of Estuarine Habitats for Fish". Griffith University. School of Environmental and Applied Science, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20060824.144508.
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The role of autotrophic production in different coastal habitats in the production of fish in estuaries is an important consideration in coastal management and conservation. In the estuarine waters of the Australian east coast, many economically important fish species occur over mudflats lacking conspicuous vegetation. I used stable isotope analysis to examine where such fish ultimately derived their nutrition, in the subtropical waters of southern Moreton Bay, Queensland, Australia. I first tested traditional processing methodologies of autotroph samples, in this case of mangrove leaves, and examined variability in mangrove isotope values at different spatial scales. Mangrove leaves processed using time-consuming grinding showed no significant difference in isotope values than coarsely broken leaf fragments. Isotope values of green leaves were not meaningfully different from yellow or brown leaves that would normally be the leaves that actually dropped on to the sediment. Future analyses therefore can use green leaves, since they are more abundant and therefore more easily collected, and can simply be processed as whole leaf fragments rather than being ground to a powder. Carbon and nitrogen isotope values varied at several spatial scales. The proportion of variability partitioned at different scales varied depending on the species of mangrove and element (C or N) analysed. To properly represent a geographic area, isotope analysis should be done on leaves collected at different locations and, especially, from different trees within locations. The autotrophic source(s) supporting food webs leading to fish production on mudflats might be either in situ microphytobenthos or material transported from adjacent habitats dominated by macrophytes. I tested the importance of these sources by measuring ?13C values of 22 fish species and six autotroph taxa (microphytobenthos on mudflats, and seagrass, seagrass epiphytic algae, mangroves, saltmarsh succulents and saltmarsh grass in adjacent habitats) in Moreton Bay. I calculated the distribution of feasible contributions of each autotroph to fishes. All fish ?13C values lay in the enriched half of the range for autotrophs. For over 90% of fishes, the top three contributing autotrophs were seagrass, epiphytes and saltmarsh grass, with median estimates of approximately 60-90% from these sources combined. Seagrass was typically ranked as the main contributor based on medians, while epiphytic algae stood out based on 75th percentile contributions. The other three sources, including MPB, were ranked in the top three contributors for only a single fish. Organic matter from seagrass meadows is clearly important at the base of food webs for fish on adjacent unvegetated mudflats, either through outwelling of particular organic matter or via a series of predator-prey interactions (trophic relay). Modelling results indicate that saltmarsh grass (Sporobolus) also had high contributions for many fish species, but this is probably a spurious result, reflecting the similarity in isotope values of this autotroph to seagrass. Carbon from adjacent habitats and not in situ microphytobenthos dominates the nutrition for this suite of 22 fishes caught over mudflats. The ultimate autotrophic sources supporting production of three commercially important fish species from Moreton Bay were re-examined by further analysing carbon and nitrogen stable isotope data. Mean isotope values over the whole estuary for fish and autotroph sources were again modelled to indicate feasible combinations of sources. Variability in isotope values among nine locations (separated by 3-10 km) was then used as a further test of the likelihood that sources were involved in fish nutrition. A positive spatial correlation between isotope values of a fish species and an autotroph indicates a substantial contribution from the autotroph. Spatial correlations were tested with a newly developed randomisation procedure using differences between fish and autotroph values at each location, based on carbon and nitrogen isotopes combined in two-dimensional space. Both whole estuary modelling and spatial analysis showed that seagrass, epiphytic algae and particulate organic matter in the water column, potentially including phytoplankton, are likely contributors to bream (Acanthopagrus australis) nutrition. However, spatial analysis also showed that mangroves were involved (up to 33% contribution), despite a very low contribution based on whole estuary modelling. Spatial analysis for sand whiting (Sillago ciliata) demonstrated the importance of two sources, mangroves and microalgae on the mudflats, considered unimportant based on whole estuary modelling. No spatial correlations were found between winter whiting (Sillago maculata) and autotrophs, either because fish moved among locations or relied on different autotrophs at different locations. Spatial correlations between consumer and source isotope values provide a useful analytical tool for identifying the role of autotrophs in foodwebs, and were used here to demonstrate that organic matter from adjacent habitats, and in some cases also in situ production of microalgae, were important to fish over mudflats. Whilst recognising that production from several habitats is implicated in the nutrition of fishes over mudflats in Moreton Bay, clearly the major source is from seagrass meadows. Organic matter deriving from seagrass itself and/or algae epiphytic on seagrass is the most important source at the base of fisheries food webs in Moreton Bay. The importance of seagrass and its epiphytic algae to production of fisheries species in Moreton Bay reinforces the need to conserve and protect seagrass meadows from adverse anthropogenic influences.
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Melville, Andrew J. "Stable Isotope Tests of the Trophic Role of Estuarine Habitats for Fish". Thesis, Griffith University, 2005. http://hdl.handle.net/10072/367080.
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The role of autotrophic production in different coastal habitats in the production of fish in estuaries is an important consideration in coastal management and conservation. In the estuarine waters of the Australian east coast, many economically important fish species occur over mudflats lacking conspicuous vegetation. I used stable isotope analysis to examine where such fish ultimately derived their nutrition, in the subtropical waters of southern Moreton Bay, Queensland, Australia. I first tested traditional processing methodologies of autotroph samples, in this case of mangrove leaves, and examined variability in mangrove isotope values at different spatial scales. Mangrove leaves processed using time-consuming grinding showed no significant difference in isotope values than coarsely broken leaf fragments. Isotope values of green leaves were not meaningfully different from yellow or brown leaves that would normally be the leaves that actually dropped on to the sediment. Future analyses therefore can use green leaves, since they are more abundant and therefore more easily collected, and can simply be processed as whole leaf fragments rather than being ground to a powder. Carbon and nitrogen isotope values varied at several spatial scales. The proportion of variability partitioned at different scales varied depending on the species of mangrove and element (C or N) analysed. To properly represent a geographic area, isotope analysis should be done on leaves collected at different locations and, especially, from different trees within locations. The autotrophic source(s) supporting food webs leading to fish production on mudflats might be either in situ microphytobenthos or material transported from adjacent habitats dominated by macrophytes. I tested the importance of these sources by measuring ?13C values of 22 fish species and six autotroph taxa (microphytobenthos on mudflats, and seagrass, seagrass epiphytic algae, mangroves, saltmarsh succulents and saltmarsh grass in adjacent habitats) in Moreton Bay. I calculated the distribution of feasible contributions of each autotroph to fishes. All fish ?13C values lay in the enriched half of the range for autotrophs. For over 90% of fishes, the top three contributing autotrophs were seagrass, epiphytes and saltmarsh grass, with median estimates of approximately 60-90% from these sources combined. Seagrass was typically ranked as the main contributor based on medians, while epiphytic algae stood out based on 75th percentile contributions. The other three sources, including MPB, were ranked in the top three contributors for only a single fish. Organic matter from seagrass meadows is clearly important at the base of food webs for fish on adjacent unvegetated mudflats, either through outwelling of particular organic matter or via a series of predator-prey interactions (trophic relay). Modelling results indicate that saltmarsh grass (Sporobolus) also had high contributions for many fish species, but this is probably a spurious result, reflecting the similarity in isotope values of this autotroph to seagrass. Carbon from adjacent habitats and not in situ microphytobenthos dominates the nutrition for this suite of 22 fishes caught over mudflats. The ultimate autotrophic sources supporting production of three commercially important fish species from Moreton Bay were re-examined by further analysing carbon and nitrogen stable isotope data. Mean isotope values over the whole estuary for fish and autotroph sources were again modelled to indicate feasible combinations of sources. Variability in isotope values among nine locations (separated by 3-10 km) was then used as a further test of the likelihood that sources were involved in fish nutrition. A positive spatial correlation between isotope values of a fish species and an autotroph indicates a substantial contribution from the autotroph. Spatial correlations were tested with a newly developed randomisation procedure using differences between fish and autotroph values at each location, based on carbon and nitrogen isotopes combined in two-dimensional space. Both whole estuary modelling and spatial analysis showed that seagrass, epiphytic algae and particulate organic matter in the water column, potentially including phytoplankton, are likely contributors to bream (Acanthopagrus australis) nutrition. However, spatial analysis also showed that mangroves were involved (up to 33% contribution), despite a very low contribution based on whole estuary modelling. Spatial analysis for sand whiting (Sillago ciliata) demonstrated the importance of two sources, mangroves and microalgae on the mudflats, considered unimportant based on whole estuary modelling. No spatial correlations were found between winter whiting (Sillago maculata) and autotrophs, either because fish moved among locations or relied on different autotrophs at different locations. Spatial correlations between consumer and source isotope values provide a useful analytical tool for identifying the role of autotrophs in foodwebs, and were used here to demonstrate that organic matter from adjacent habitats, and in some cases also in situ production of microalgae, were important to fish over mudflats. Whilst recognising that production from several habitats is implicated in the nutrition of fishes over mudflats in Moreton Bay, clearly the major source is from seagrass meadows. Organic matter deriving from seagrass itself and/or algae epiphytic on seagrass is the most important source at the base of fisheries food webs in Moreton Bay. The importance of seagrass and its epiphytic algae to production of fisheries species in Moreton Bay reinforces the need to conserve and protect seagrass meadows from adverse anthropogenic influences.Thesis (Masters)
Master of Philosophy (MPhil)
School of Environmental and Applied Science
Full Text
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au, M. Wildsmith@murdoch edu, i Michelle Wildsmith. "Relationships between benthic macroinvertebrate assemblages and habitat types in nearshore marine and estuarine waters along the lower west coast of Australia". Murdoch University, 2007. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20081029.93910.
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The following four broad aims were addressed in this study. (1) To ascertain whether the characteristics of the benthic macroinvertebrate assemblages within the different nearshore marine habitat types identified by Valesini et al. (2003) on the lower west coast of Australia differ significantly, and whether the pattern of those spatial differences matches those among the environmental characteristics that were used to distinguish those habitat types; (2) To develop a quantitative approach for classifying nearshore habitats in estuarine waters that employs readily-available data for a range of enduring environmental characteristics, and to use that approach to classify the various habitat types present in nearshore waters of the Swan-Canning Estuary on the lower west coast of Australia; (3) To test the hypothesis that the characteristics of the benthic macroinvertebrate assemblages in the in the Swan-Canning Estuary differ significantly among nearshore habitat types, and that the pattern of those differences matches that among the environmental characteristics used to distinguish those habitat types and (4) To test the hypothesis that, as a result of environmental changes in the Swan-Canning Estuary, the characteristics of the benthic macroinvertebrate assemblages at various habitats in this estuary in 1986/7 differ from those in 2003/4.
To address the first aim, benthic macroinvertebrates were sampled seasonally for one year in the subtidal waters and intertidal zone (upper and lower swash zones) at the six nearshore habitat types that were identified by Valesini et al. (2003) on the lower west coast of Australia. The habitat types, which differed mainly in the extent of their exposure to wave activity and whether seagrass and/or nearshore reefs were present, had been distinguished quantitatively using values for a suite of seven statistically-selected enduring environmental characteristics. The faunal samples yielded a total of 121 species representing eight phyla, among which the Polychaeta, Malacostraca and Bivalvia were the most speciose classes and contributed ~ 38, 23 and 10%, respectively, to the total number of individuals. The total number of species and mean density of macroinvertebrates was far greater at the most protected habitat type (1), which also contained dense beds of seagrass, than at any other habitat type, i.e. 70 species and 209.2 individuals 0.1 m-2, compared to 32 species and 36.9 individuals 0.1 m-2 at the most exposed habitat type (6), which had a substrate comprised only of sand. Differences among habitat type influenced the benthic macroinvertebrate species composition to a greater extent than differences among either zones or seasons. Significantly different faunal compositions were detected among those latter two factors only at the most protected habitat type. The faunal assemblage at habitat type 1 was clearly the most distinct from those at the other five habitat types, particularly in the subtidal zone (R-statistics=0.642-0.831, p=0.1%), and was typified by five abundant polychaete species that were adapted to deposit-feeding. In contrast, the fauna at habitat type 6 was typified by four crustacean species and a species of bivalve and polychaete, whose mobility and tough external surface facilitated their survival and feeding in those turbulent waters. The extents of the differences in species composition among the six habitat types was significantly matched with that among the suite of enduring environmental characteristics that distinguished those habitat types, particularly in the case of the subtidal zone (Rho=0.676). Such results indicated that the environmental variables used to distinguish the nearshore habitat types could be used to reliably predict the types of benthic macroinvertebrate species likely to occur at any site along the lower west coast of Australia.
The above biological validation of the nearshore marine habitat classification scheme developed by Valesini et al. (2003) provided the justification for the approach to the second broad aim of this study, namely to develop a quantitative scheme for classifying habitat types in the Swan-Canning Estuary. This approach was similar to that employed by Valesini et al. (2003) in that it considers that differences among habitat types are well reflected by differences in a suite of enduring environmental variables. However, it improves on that earlier method by employing a completely objective and quantitative approach.
Thus, a large number of environmentally-diverse nearshore sites (102) were initially selected throughout the Swan-Canning Estuary and a suite of 13 enduring environmental variables quantified at each using remotely-sensed images of the estuary in a Geographic Information System. Such variables were chosen to reflect either (i) the type of substrate and submerged vegetation present, (ii) the extent of exposure to wave action or (iii) the location of the site within the estuary with respect to its vicinity to marine and fresh water sources. These data were then subjected to the CLUSTER routine and associated SIMPROF procedure in the PRIMER v6 multivariate statistical package to quantitatively identify those groups of sites that did not differ significantly in their environmental characteristics, and thus represented habitat types. Eighteen habitat types were identified, which were shown to well reflect spatial differences in a suite of non-enduring water quality and sediment characteristics that were measured in situ at a range of estuarine sites during both summer and winter in 2005 (Rho=0.683 and 0.740, respectively, p=0.1%). However, those latter environmental characteristics required far more time in the field and laboratory to quantify than the enduring variables used to identify the habitat types.
Benthic macroinvertebrates were sampled during summer and winter in 2005 in the shallow subtidal regions (~1 m depth) at sites representing eight of the habitat types identified in the Swan-Canning Estuary. These samples contained a total of 51 and 36 species during summer and winter, respectively, and, in both seasons, represented nine phyla, namely Annelida, Crustacea, Mollusca, Sipuncula, Nematoda, Platyhelminthes, Cnidaria, Uniramia and Nemertea. The compositions of the benthic macroinvertebrate assemblages differed significantly among habitat types and, to a similar extent, between seasons (Global R-statistic=0.408 and 0.409, respectively, p=0.1%). However, the spatial differences were considerable greater in winter than in summer (Global R-statistic=0.536 vs 0.280, p=0.1%), presumably due to the greater spatial variation in particular non-enduring in situ environmental characteristics, such as redox depth and salinity. While the number of species, overall density and taxonomic distinctness of benthic macroinvertebrates also differed significantly among habitats, those variables differed to a greater extent between seasons, being greater in winter than in summer. While the measures of taxonomic distinctness tended to be greater at habitat types located in the lower to middle reaches, i.e. habitat types 6, 7, 9, 10, 13 and 18, than the upper reaches i.e. habitat types 1 and 3, the number of species and overall density reflected this trend only during winter. During summer, the mean numbers of species at habitat types 1, 3, 6 and 10 (3.4-6.0) were significantly lower than those at habitat types 7, 13, and 18 (8.8-10.9), whereas the overall density of benthic macroinvertebrates was far greater at habitat type 7 (32260 individuals 0.1 m-2)than at any other habitat type in this season (3135-18552 individuals 0.1 m-2).
Overall, the greatest differences in assemblage composition occurred between those at habitat types 1 and 18 (R-statistic=0.669, p=0.1%), which were located in the uppermost region of the estuary and the lower reaches of the basin, respectively, and differed to the greatest extent in their enduring environmental characteristics. The assemblage at habitat type 1, and also that at habitat type 3, located just downstream, were relatively distinct from those at all other habitat types, particularly during winter (R-statistics=0.666-0.993, p=0.1%). The fauna at the first of these habitat types was relatively depauperate, containing low numbers of species and densities, and was characterised by the polychaetes Leitoscoloplos normalis and Ceratonereis aequisetis and the bivalve Arthritica semen. The assemblage at habitat type 3 was also characterised by those three species and the amphipod Paracorophium minor and the polychaete Boccardiella limnicola. In contrast, the assemblage at habitat type 18 was characterised by a more diverse assemblage, i.e. the polychaetes Capitella capitata, C. aequisetis, L. normalis and Pseudopolydora kempi, the amphipods, Grandidierella propodentata and Corophium minor and the bivalve Sanguinolaria biradiata. The number of species was among the highest at this habitat type during both seasons, which was also reflected in the high taxonomic diversity, and the overall density was the highest in winter and second highest in summer. Despite the above faunal differences, those between assemblages at habitat types 7 and 9, which were both located in the basin of the Swan-Canning Estuary, were similar in magnitude to those that occurred between pairs of habitat types located in two different regions of the estuary. Although both habitat types 7 and 9 were characterised by a similar suite of species, i.e. Oligochaete spp., C. aequisetis, C. capitata, C. minor, G. propodentata, L. normalis, and S. biradiata, the substantial differences in assemblage composition between these habitat types in both summer and winter (R-statistics=0.570 and 0.725, respectively) was due to marked differences in the relative contributions of each of these species.
Significant and strong correlations were shown to exist in both summer and winter between the pattern of differences in the benthic macroinvertebrate assemblages among habitat types and that among the enduring environmental characteristics used to identify those habitat types (Rho=0.625 and 0.825, respectively, p=0.1%). Furthermore, these correlations were greater than those obtained between the benthic macroinvertebrate fauna and any combination of the non-enduring environmental characteristics (i.e. water quality and sediment parameters) recorded in situ at each habitat type (Rho=0.508 and 0.824, in summer and winter, respectively, p=o.1%). This demonstrates the greater capacity of surrogate enduring environmental characteristics to account for differences in the range of variables that may influence the distribution of benthic invertebrate fauna. Thus, the lists of characteristic benthic macroinvertebrate taxa produced for each of the eight habitat types studied in the Swan-Canning Estuary provide a reliable benchmark by which to gauge any future changes in those fauna. Moreover, these results indicate that the above habitat classification scheme can be used to reliably predict the types of benthic macroinvertebrate fauna that are likely to occur at any nearshore site of interest in this estuarine system.
The final component of this study showed that the benthic macroinvertebrate assemblages at four sites in the middle reaches of the Swan-Canning Estuary in 2003/4 differed significantly from those recorded at the same sites in 1986/7. Such differences were reflected in (1) changes in the relative densities of a suite of ten species that were responsible for distinguishing the faunas in these two periods, (2) the absence of 22 rare species in 2003/4 (i.e. 42% of the number of species recorded in 1986/7), (3) the presence of 17 new species in 2003/4, including an abundant polychaete that is likely to have been introduced and (4) a far greater extent of seasonal variation in the number of species and densities of benthic macroinvertebrates in 2003/4. Such changes are likely to be related to lower sediment oxygen levels in certain seasons in 2003/4, as well as an altered hydrological regime due to increased temperatures and decreased rainfall in that more recent period. The fact that these changes have occurred within the Swan-Canning Estuary highlights the need for effective management tools, such as the habitat classification scheme and associated faunal survey undertaken in this study. Such data will provide a sound basis by which to examine the ways in which fauna vary spatially within the system, and allow for the establishment of comprehensive benchmarks for detecting future changes.
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Mazumder, Debashish, i res cand@acu edu au. "Contribution of Saltmarsh to Temperate Estuarine Fish in Southeast Australia". Australian Catholic University. School of Arts and Science (NSW, 2004. http://dlibrary.acu.edu.au/digitaltheses/public/adt-acuvp47.09042006.
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Saltmarsh is an important coastal habitat located in the littoral zone of estuaries. Australian saltmarsh area is decreasing due to agricultural and urban development and invasion by mangrove. The aim of the study was to assess the contribution made by saltmarsh as a habitat and a source of food items for fish. Three saltmarsh sites were studied, with Towra Point chosen as a site for detailed ecological study. When corrected for water volume, fish densities were found to be higher within the saltmarsh compared to the adjacent mangrove. Although the fish assemblages in saltmarshes differed significantly from mangroves the overall ratio between commercially and ecologically valuable species in these habitats are similar, a result suggesting the importance of temperate saltmarsh as habitat for economically important fish. Significant export of crab larva from saltmarsh (average crab larval abundance 2124.63 m-3 outgoing water) is a positive contribution to the estuarine food chain supplementing the nutritional requirements of estuarine fish. While the diet of the crabs producing this larvae seems dependant on the saltmarsh environment (given the contrasting isotopic signatures of Sesarma erythrodactyla in saltmarsh and mangrove, and the similarity of isotopic signatures in the saltmarsh for Sesarma erythrodactyla and Helograpsus haswellianus), the crabs do not seem to be dependent on any of the common species of saltmarsh plant, but rather depend on particulate organic matter (POM) derived from local and other sources. Crab larva are a prey item for many estuarine fish, including commercially important species, as evidenced by gut content analysis of fish visiting the saltmarsh flats during spring tides. The results strongly suggest that emphasis be given to ecosystembased management for an estuary rather than component (e.g., vegetation) based managed as defined by the Fisheries Management Act (1994) and the State Environmental Planning Policy 14.
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Bennett, B. A. "The utilization of littoral and estuarine habitats by fish in the Southwestern Cape". Doctoral thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/8421.
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Includes bibliographies.This thesis examines the utilization of rocky intertidal, sandy-beach surf-zone and estuarine habits by fishes on the southwestern Cape coast of South Africa. It has there central objectives: 1) to determine the species composition, abundance, size structure and seasonality of fish and to examine the extent to which they are influenced by environmental factors; 2) to describe the diets and patterns of feeding of the fish and to assess their impact on the food resources; and 3) to determine the importance of these habitats as nursery areas for juvenile fish.
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Yerman, Michelle N., University of Western Sydney, of Science Technology and Environment College i School of Natural Sciences. "Temperate urban mangrove forests : their ecological linkages with adjacent habitats". THESIS_CSTE_NSC_Yerman_M.xml, 2003. http://handle.uws.edu.au:8081/1959.7/652.
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Estuarine habitats along the temperate south-eastern shores of Australia are generally made up of salt marsh, mangrove forests and seagrass beds. In urban areas these habitats have been progressively fragmented as a result of population increase and industrial expansion. Salt marshes in particular have been vulnerable to urban expansion and reclamation because of their close proximity to densely populated areas, while mangrove forests have been less often reclaimed because of frequent tidal inundation. The effect of reclamation of salt marshes on the biotic assemblages and functioning of mangrove forests with an adjacent salt marsh, park or bund wall was examined at nine separate locations on the Parramatta River, Sydney NSW. A mensurative approach was used to describe the patterns of distribution and abundance of macro fauna at several temporal and spatial scales. The implications for management are that salt marshes are an integral part of estuaries, and smaller patches of salt marsh are just as important as larger patches in maintaining the diversity of faunal assemblages and ecosystem functioning in mangrove forests in urban areasMaster of Science (Hons)
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Meynecke, Jan-Olaf. "Influence of Climate and Estuarine Habitat Characteristics on Coastal Fisheries - A Case Study for Queensland, Australia". Thesis, Griffith University, 2008. http://hdl.handle.net/10072/365785.
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Abstract: The primary data sources for this study were (1) 17 years of commercial fish catch data from over 30 selected estuarine fish species or species groups; and (2) estuarine habitat maps for Queensland, Australia. Queensland appears to be the best study region as it had the largest extent of soft sediment estuarine habitats, comprising seagrass, salt marsh and mangroves, and offers long-term commercial fish catch data compared to other states in Australia. As a first step, the relationship between catch (both as catch-per-unit-effort (CPUE) and total catch) for commercially caught species in their dominant fisheries (trawl, line, net or pot fisheries) and estuarine geomorphic spatial metrics were extracted from digital habitat maps in geographic information systems (GIS). For preliminary analyses, I examined 13 geographical regions in Queensland based on their importance to commercial fisheries. Spatial metric characteristics such as Euclidean distance, patch density and landscape connectivity for 273 estuaries along the Queensland coast were then calculated within 90 fish catch grids, which provided inshore fish catch data from 21 species groups.
The collective spatial characteristics of estuarine habitats such as size and structural connectivity showed significant correlation with fish catch, with r2 values > 0.7 for 17 commercial species groups. More detailed multiple regression analysis and non-metric multidimensional scaling (nMDS) plots showed significant links between geomorphic coastal features such as structural connectivity and nearshore fisheries production. The relationship was best explained by connectivity indices for mangroves, salt marsh and channels, further suggesting the fundamental importance of connected tidal wetlands to the fish catch.
Climate-driven dependencies of fish catch were explored by using CPUE, rainfall, coastal air temperature and the Southern Oscillation Index (SOI) and catch time-series for specific combinations of climate, seasons and regions. Surplus production models where applied to the commercial fish catch data using the program CLIMPROD. In addition to habitat configuration, climate, particularly rainfall, played a major role in the species composition of the fish catch. Up to 30 % of Queensland’s total fish catch and up to 80 % of the barramundi catch variation for specific regions were explained by rainfall, often with a time-lag response to rainfall events. Temperature had similar influences on fish and prawn catches, with high temperatures having a negative effect on the prawn catch in the Gulf of Carpentaria.
The importance of estuary-scale habitat connectivity to fish populations was assessed by studying fish movement in relation to the extent of flooding for several commercially and recreationally important species in and out of a small mangrove creek using a stationary passive integrated transponder (PIT) system, augmented by underwater digital video recorders (DVRs) for visual sensing. A high-resolution digital elevation model derived from airborne light detection and ranging (LIDAR) and aerial imagery was used to estimate inundation pattern of intertidal habitats to compare with movement of PIT tagged fish. Investigations of fish movement at a detailed scale confirmed the broad-scale findings that habitat connectivity and close spatial proximity of resources are key factors for estuary-dependent fish species in tide-dominated systems to access different habitats. Access to habitat resources such as mangroves is more limited in time than previously thought and is dependent on fish species and size, thus suggesting importance of other adjoining habitats. Fish species and size also affected time of residency and diel pattern of habitat use.
The analyses presented in this thesis also allow an evaluation of the economic consequences of climate parameters on estuarine fisheries. Species-specificity in climate-catch relationships suggested a strong need to develop forecast models and manage estuaries for future climate change by adjusting the quota for the more sensitive species. In addition, my findings on the role of estuarine habitat connectivity could guide the construction of a network of protected marine areas of various structural configurations that can optimise ecosystem services. The demonstrated value of habitat connectivity further warns against future reduction of connectivity by habitat destruction and climate change. The new techniques developed for assessing the spatial ecology of estuarine fish and their habitat utilisation and site fidelity behaviour will assist evaluation of the role of estuarine habitat inter-dependencies in supporting coastal fish populations.
The fish catch data set used for fisheries management is valid for broad-scale investigations. However, it can be insufficient for managing certain stocks, e.g., fish targeted by recreational fishers. Data sets can be significantly improved by in-corporating locally collected recreational fish catch data, which can provide detailed information for particular river systems and allow better assessments of potential overfishing.
The results of this study suggest that sound ecosystem-based fisheries management requires a diversity of information, an improved catch record system, a species-specific approach to managing the impact of climate change, and ecologically meaningful protection areas with high habitat connectivity.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment.
Science, Environment, Engineering and Technology
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Branson, Adam. "A comparison of fish assemblages utilizing estuarine and ocean surf habitats in southeastern North Carolina". View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-2/bransona/adambranson.pdf.
Pełny tekst źródłaKsiążki na temat "Estuarine habitats"
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Giannico, Guillermo Roberto. The effects of tide gates on estuarine habitats and migratory fish. [Corvallis, Or.]: Sea Grant Oregon, Oregon State University, 2004.
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Aitkin, J. Kevin. The importance of estuarine habitats to anadromous salmonids of pacific northwest: A literature review. Lacey, Wash. (510 Desmond Dr., SE, Suite 102, Lacey 98503-1273): U.S. Fish & Wildlife Service, Western Washington Office, Aquatic Resources Division, 1998.
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Aitkin, J. Kevin. The importance of estuarine habitats to anadromous salmonids of pacific northwest: a literature review. Lacey, Wash. (510 Desmond Dr., SE, Suite 102, Lacey 98503-1273): U.S. Fish & Wildlife Service, Western Washington Office, Aquatic Resources Division, 1997.
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Geological Survey (U.S.), red. Coastal habitats of the Elwha River, Washington: Biological and physical patterns and processes prior to dam removal. Reston, Va: U.S. Dept. of the Interior, U.S. Geological Survey, 2011.
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Seebacher, Lizbeth. Restoration of coastal estuarine habitats within previously diked wetlands in the South Slough National Estuarine Research Reserve, Charleston, Oregon. Charleston, Or: South Slough National Estuarine Research Reserve, 1997.
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Hinton, Susan A. Fishes, shrimp, benthic invertebrates, and sediment characteristics in intertidal and subtidal habitats at Rice Island and Miller Sands, Columbia River Estuary, 1991. Seattle, Wash: Coastal Zone and Estuarine Studies Division, Northwest Fisheries Science Center, 1992.
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State of the Estuary Conference (8th 2007 Oakland, Calif.). A greener shade of blue?: State of the San Francisco Bay-Delta estuary 2008. [Oakland, Calif.]: San Francisco Estuary Project, 2007.
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West Coast Symposium on the Effects of Tide Gates on Estuarine Habitats and Fishes (2006 South Slough National Estuarine Research Reserve). Proceedings of the West Coast Symposium on the Effects of Tide Gates on Estuarine Habitats and Fishes, October 31-November 2, 2006, South Slough National Estuarine Research Reserve. Redaktorzy Giannico Guillermo Roberto 1960-, Cooper Rick i Oregon State University. Sea Grant College Program. Charleston, Or: Oregon State University, Oregon Sea Grant, 2007.
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West Coast Symposium on the Effects of Tide Gates on Estuarine Habitats and Fishes (2006 South Slough National Estuarine Research Reserve). Proceedings of the West Coast Symposium on the Effects of Tide Gates on Estuarine Habitats and Fishes, October 31-November 2, 2006, South Slough National Estuarine Research Reserve. Redaktorzy Giannico Guillermo Roberto 1960-, Cooper Rick i Oregon State University. Sea Grant College Program. Charleston, Or: Oregon State University, Oregon Sea Grant, 2007.
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West Coast Symposium on the Effects of Tide Gates on Estuarine Habitats and Fishes (2006 South Slough National Estuarine Research Reserve). Proceedings of the West Coast Symposium on the Effects of Tide Gates on Estuarine Habitats and Fishes, October 31-November 2, 2006, South Slough National Estuarine Research Reserve. Redaktorzy Giannico Guillermo Roberto 1960-, Cooper Rick i Oregon State University. Sea Grant College Program. Charleston, Or: Oregon State University, Oregon Sea Grant, 2007.
Znajdź pełny tekst źródłaCzęści książek na temat "Estuarine habitats"
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Kimirei, I. A., M. M. Igulu, M. Semba i B. R. Lugendo. "Small Estuarine and Non-Estuarine Mangrove Ecosystems of Tanzania: Overlooked Coastal Habitats?" W Estuaries of the World, 209–26. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-25370-1_13.
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Raposa, Kenneth B., Charles T. Roman i James F. Heltshe. "Monitoring Nekton as a Bioindicator in Shallow Estuarine Habitats". W Coastal Monitoring through Partnerships, 239–55. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0299-7_21.
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Hodda, Mike, i Walter Traunspurger. "Nematodes from extreme and unusual freshwater habitats." W Ecology of freshwater nematodes, 109–50. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789243635.0004.
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Abstract This chapter discusses the ecology and biogeography of nematodes from freshwater environments that are extreme in temperature, chemical composition, variability, or isolation. Described and compared are the compositions of nematode faunas from hot or mineral springs, pools and bogs in polar regions, intermittent lakes or pools or streams, freshwater pools in bromeliads or tree hollows, stemflow, fresh groundwaters, and caves. Comparisons of the nematode faunas from these extreme habitats with those from more typical freshwater environments are also provided. Also discussed are nematodes with evolutionary affinities to freshwaters that are found in estuarine sediments along with nematodes from freshwaters with evolutionary affinities to otherwise marine taxa. The emphasis is on broad ecological patterns rather than on detailed species interactions with the various freshwater environments. Thus, the chapter focuses on genera or higher taxa rather than species.
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Thom, Ronald M., i Amy B. Borde. "Estuarine Habitat Restoration". W Encyclopedia of Estuaries, 273–85. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-8801-4_78.
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Airoldi, Laura, i Michael W. Beck. "Habitat Loss". W Encyclopedia of Estuaries, 349. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-8801-4_155.
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Ortiz-Burgos, Selene. "Habitat Complexity". W Encyclopedia of Estuaries, 347–49. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-8801-4_234.
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Drexler, Judith Z. "Tidal Freshwater Habitat". W Encyclopedia of Estuaries, 683–85. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-8801-4_368.
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Duberstein, Jamie A., i Ken W. Krauss. "Forested Wetland Habitat". W Encyclopedia of Estuaries, 334–38. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-8801-4_387.
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Rodríguez, José F., i Alice Howe. "Estuarine Wetland Ecohydraulics and Migratory Shorebird Habitat Restoration". W Ecohydraulics, 375–94. Chichester, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118526576.ch22.
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Burger, Joanna, i Michael Gochfeld. "Barnegat Bay and Other Northeast Estuaries". W Habitat, Population Dynamics, and Metal Levels in Colonial Waterbirds, 39–70. Boca Raton : Taylor & Francis, 2016. | Series: CRC marine science series ; 36: CRC Press, 2016. http://dx.doi.org/10.1201/9780429159435-3.
Pełny tekst źródłaStreszczenia konferencji na temat "Estuarine habitats"
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Chen, XinJian. "Responses of Simulated Low Salinity Habitats to the Uncertainties of Gauged and Ungauged Flows in the Myakka River Estuary in Florida". W International Conference on Estuarine and Coastal Modeling 2012. Reston, VA: American Society of Civil Engineers, 2012. http://dx.doi.org/10.1061/9780784412411.00026.
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Pruden, Matthew, Gregory P. Dietl, John C. Handley i Jansen Smith. "TOWARDS A MOLLUSC-ONLY GEOHISTORICAL M-AMBI FOR ESTABLISHING REMEDIATION BASELINES IN COASTAL AND ESTUARINE HABITATS". W GSA Connects 2021 in Portland, Oregon. Geological Society of America, 2021. http://dx.doi.org/10.1130/abs/2021am-370679.
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Beegle-Krause, C. J., Tiffany Vance, Debbie Reusser, David Stuebe i Eoin Howlett. "Pelagic Habitat Visualization: The Need for a Third (and Fourth) Dimension: HabitatSpace". W 11th International Conference on Estuarine and Coastal Modeling. Reston, VA: American Society of Civil Engineers, 2010. http://dx.doi.org/10.1061/41121(388)12.
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Maristany, Luis M., Aaron G. Horine i Paul D. Carangelo. "La Quinta Terminal Mitigation: Dredged Material Beneficial Reuse for Estuarine Habitat Creation". W 15th Triennial International Conference. Reston, VA: American Society of Civil Engineers, 2019. http://dx.doi.org/10.1061/9780784482629.007.
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AUGUSTIN, LAUREN N., DANIEL J. HEILMAN i DENNIS D. ROCHA. "RESTORING ESTUARINE HABITAT IN GALVESTON WEST BAY THROUGH BENEFICIAL USE OF DREDGED SEDIMENTS". W The Proceedings of the Coastal Sediments 2011. World Scientific Publishing Company, 2011. http://dx.doi.org/10.1142/9789814355537_0192.
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Mendelsohn, Daniel L., Steve Peene i Ray Pribble. "Modeling the Impacts of Water Withdrawls on the Thermal Regime of the Weeki Wachee River Winter Manatee Habitat". W International Conference on Estuarine and Coastal Modeling 2012. Reston, VA: American Society of Civil Engineers, 2012. http://dx.doi.org/10.1061/9780784412411.00004.
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Rooper, C. N., D. A. Armstrong i D. R. Gunderson. "Habitat use by juvenile Dungeness crabs in coastal nursery estuaries". W Crabs in Cold Water Regions: Biology, Management, and Economics. Alaska Sea Grant, University of Alaska Fairbanks, 2002. http://dx.doi.org/10.4027/ccwrbme.2002.44.
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Bragadin, Gianni Luigi, Maurizio Luca Mancini i Alessandro Turchetto. "WASTEWATER DISCHARGE BY ESTUARINE TRANSITION FLOW AND THERMOALINE CONDITIONING IN SHORE HABITAT NEAR CESENATICO BREAKWATERS". W Proceedings of the 5th Coastal Structures International Conference, CSt07. World Scientific Publishing Company, 2009. http://dx.doi.org/10.1142/9789814282024_0097.
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MCPHERSON, RONALD, PHILIP BLACKMAR i DANIEL HEILMAN. "RESTORING ESTUARINE HABITAT IN GALVESTON WEST BAY THROUGH PLACEMENT OF DREDGED SEDIMENTS: MONITORING AND LESSONS LEARNED". W Coastal Sediments 2015. WORLD SCIENTIFIC, 2015. http://dx.doi.org/10.1142/9789814689977_0090.
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Tarokh, Mahmoud, i Minjuan Wang. "Development of a Robotic Helicopter for Monitoring Pollution and Habitat in Estuaries". W 2012 8th International Conference on Intelligent Environments (IE). IEEE, 2012. http://dx.doi.org/10.1109/ie.2012.61.
Pełny tekst źródłaRaporty organizacyjne na temat "Estuarine habitats"
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Eisemann, Eve, Catherine Thomas, Matthew Balazik, Damarys Acevedo-Mackey i Safra Altman. Environmental factors affecting coastal and estuarine submerged aquatic vegetation (SAV). Engineer Research and Development Center (U.S.), październik 2021. http://dx.doi.org/10.21079/11681/42185.
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Submerged aquatic vegetation (SAV) growing in estuarine and coastal marine systems provides crucial ecosystem functions ranging from sediment stabilization to habitat and food for specific species. SAV systems, however, are sensitive to a number of environmental factors, both anthropogenic and natural. The most common limiting factors are light limitation, water quality, and salinity, as reported widely across the literature. These factors are controlled by a number of complex processes, however, varying greatly between systems and SAV populations. This report seeks to conduct an exhaustive examination of factors influencing estuarine and coastal marine SAV habitats and find the common threads that tie these ecosystems together. Studies relating SAV habitats in the United States to a variety of factors are reviewed here, including geomorphological and bathymetric characteristics, sediment dynamics, sedimentological characteristics, and water quality, as well as hydrologic regime and weather. Tools and methods used to assess each of these important factors are also reviewed. A better understanding of fundamental environmental factors that control SAV growth will provide crucial information for coastal restoration and engineering project planning in areas populated by SAVs.
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Baptista, António M. Estuarine Habitats for Juvenile Salmon in the Tidally-Influenced Lower Columbia River and Estuary : Reporting Period September 15, 2008 through May 31, 2009. Office of Scientific and Technical Information (OSTI), sierpień 2009. http://dx.doi.org/10.2172/965262.
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Buckley, Anna. Estuarine Habitat Mitigation in Oregon: Policy Review, Analysis, and Recommended Improvements. Portland State University, czerwiec 2006. http://dx.doi.org/10.15760/mem.33.
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Bottom, Daniel L., Antonio Baptista, Jennifer Burke, Lance Campbell, Edmundo Casillas, Susan Hinton, David A. Jay, Mary A. Lott, George McCabe i Regan McNatt. Estuarine Habitat and Juvenile Salmon: Current and Historical Linkages in the Lower Columbia River and Estuary. Fort Belvoir, VA: Defense Technical Information Center, grudzień 2011. http://dx.doi.org/10.21236/ada581333.
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Jay, David A. Historic Habitat Opportunities and Food-Web Linkages of Juvenile Salmon in the Columbia River Estuary and Their Implications for Managing River Flows and Restoring Estuarine Habitat, Physical Sciences Component, Progress Report. Office of Scientific and Technical Information (OSTI), sierpień 2009. http://dx.doi.org/10.2172/965263.
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Garono, Ralph, i Rob Robinson. Estuarine and Tidal Freshwater Habitat Cover Types Along the Lower Columbia River Estuary Determined from Landsat 7 Enhanced Thematic Mapper (ETM+) Imagery, Technical Report 2003. Office of Scientific and Technical Information (OSTI), październik 2003. http://dx.doi.org/10.2172/962829.
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Saillant, Eric, Jason Lemus i James Franks. Culture of Lobotes surinamensis (Tripletail). Mississippi Department of Marine Resources, styczeń 2014. http://dx.doi.org/10.18785/ose.001.
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The Tripletail, Lobotes surinamensis, is a pelagic fish found in tropical and sub-tropical waters of all oceans. Tripletails are often associated with floating debris and make frequent incursions in bays and estuaries where they are targeted by recreational fishermen. In Mississippi waters the species is typically present during the late spring and summer season that also correspond to the period of sexual maturation and spawning (Brown-Peterson and Franks 2001). Tripletail is appreciated as a gamefish but is also prized for its flesh of superior quality. The fast growth rate of juveniles in captivity documented by Franks et al. (2001) and the excellent quality of Tripletail flesh both contribute to the potential of this species for marine aquaculture. In addition, the production of cultured juveniles would be precious to develop a better understanding of the biology, early life history and habitat use of Tripletail larvae and juveniles, a topic largely undocumented to date, through experimental releases and controlled studies. The culture of tripletail thus supports the Tidelands Trust Fund Program through improved conservation of natural resources, potential enhancement of fisheries productivity and potential development of a new economic activity on the Gulf coast producing tripletail via aquaculture. The Objective of this project was to initiate development of methods and techniques needed to spawn captive held tripletail broodfish and raise their offspring to evaluate their growth and development in captivity. In this report we will present the results of studies aiming to develop methods and protocols for captive spawning of tripletail and the first data obtained on the early development of tripletail larvae. A major issue that was encountered with tripletail broodstock development during the project lied in the difficulties associated with identifying the sex of adults caught in the wild and candidates for being incorporated in mating sets for spawning. This issue was addressed during the course of the project by examining the potential of a non-lethal method of hormonal sexing. The results of these preliminary investigations are presented in the third part of this report. All protocols used in the project were determined with the guidance of the Institutional Animal Care and Use Committee (IACUC) of the University of Southern Mississippi (USM IACUC protocol number 10100108).