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Jennings, Jennifer L. "Mountain dolphins." Connect to this title online, 2008. http://etd.lib.clemson.edu/documents/1211389267/.
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Reddy, Kasturi. "The reproduction biology of four species of South African dolphins." Thesis, Rhodes University, 1996. http://hdl.handle.net/10962/d1005441.
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Seasonality of reproduction in common dolphins (Delphinus delphis), bottlenosed dolphins (Tursiops aduncus), striped dolphins (Stenella coeruleoalba) and humpbacked dolphins (Sousa chinensis) was examined using standard light microscope techniques. In the males four stages of testicular development could be identified. Individuals less than 2.26m in length and 105kg in mass had testes that contained small seminiferous tubules (0.048mm ± O.Olmm in diameter) and were classified either as juveniles (gonocytes present) or inactive (no gonocytes). Adults whose testes contained spermatozoa were said to be in late spermatogenesis while those whose testes contained no spermatids or spermatozoa were referred to as being in early spermatogenesis. In the males of D. delphis, T. aduncus and S. chinensis, late spermatogenesis occurred throughout the year and there was no significant difference in the monthly mean seminiferous tubule diameters (p > 0.05) within species. I conclude therefore that in these three species spermatogenesis is aseasonal. No conclusions about seasonality of spermatogenesis could be made for S. coeruleoalba owing to the small sample size. Large Graafian follicles occurred in the ovaries of all four species in most months of the year. However, the presence of Graafian follicles can not be taken as an indication of timing of reproduction since they may be remnants of follicles that have not yet degenerated. In D. delphis, T. aduncus and S. coeruleoalba luteal bodies (corpora albicans or corpora lutea) occurred in most months of the year. Active corpora lutea will be present in all months, in some members of the population, since gestation is approximately 12 months. The sperm structure of D. delphis was examined by scanning electron microscopy. The sperm of D. delphis is essentially similar to that described for two other species of Cetacea (Physeter catodon and Tursiops aduncus), having an ellipsoidally shaped head and a short mid-piece with nine mitochondria. The sperm dimensions for D. delphis were head length, 4.4pm; head width, 2.0pm and mid-piece length, 2.4pm. An analysis of foetal age in D. delphis showed that the majority of the foetuses were conceived in January with birth occurring the following summer (December), suggesting that reproduction is seasonal. Neonates of T. aduncus were found throughout the year suggesting aseasonal reproduction. Foetal material was not available for S. coeruleoalba and S. chinensis. Seasonality of reproduction in the four species of dolphins studied has been discussed in relation to feeding, migration and worldwide distribution of the species.
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Fleming, Kimberly Hoover. "The social structure, behavior, and occurrence of bottlenose dolphins in relation to shrimp trawlers in Southport, North Carolina /." Electronic version (PDF), 2004. http://dl.uncw.edu/etd/2004/flemingk/kimfleming.pdf.
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Heinrich, Sonja. "Ecology of Chilean dolphins and Peale's dolphins at Isla Chloé, southern Chile /." St Andrews, 2006. http://hdl.handle.net/10023/365.
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Heinrich, Sonja. "Ecology of Chilean dolphins and Peale's dolphins at Isla Chiloe, southern Chile." Thesis, University of St Andrews, 2006. http://hdl.handle.net/10023/365.
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Information on the ecology of sympatric species provides important insights into how different animals interact with their environment, with each other, and how they differ in their susceptibility to threats to their survival. In this study habitat use and population ecology of Chilean dolphins (Cephalorhynchus eutropia) and sympatric Peale's dolphins (Lagenorhynchus australis) were investigated in the Chiloe Archipelago in southern Chile from 2001 to 2004. Distribution data collected during systematic boat-based sighting surveys revealed a distinct pattern of small-scale habitat partitioning, probably reflecting differences in foraging strategies and habitat preference. Chilean dolphins were sighted consistently in the same selected bays and channels in southern Chiloe. Peale's dolphins were distributed over wider areas, and were more frequently encountered in central Chiloe. Spatial overlap between both dolphin species and mariculture farms (for mussels and salmon) was extensive. Predictive habitat modelling using logistic regression in a model selection framework proved a useful tool to determine critical habitat from absence-presence data and enviromental parameters. Chilean dolphins preferred shallow waters (< 20 m) close to shore (< 500 m) with estuarine influence. Peale's dolphins also occurred predominantly in shallow nearshore waters, but preferred more exposed shores with sandy shoals and were found further from rivers and mussel farms than Chilean dolphins. Analysis of ranging and movement patterns revealed small-scale site fidelity and small ranging patterns of individually identifiable Chilean dolphins. Individuals differed in their site preference and range overlap suggesting spatial partitioning along environmental and social parameters within the population. Individual Peale's dolphins were resighted less regularly, showed only limited or low site fidelity and seemed to range beyond the boundaries of the chosen study areas. Mark-recapture methods applied to photo-identification data produced estimates of local population sizes of 59 Chilean dolphins (95% CI= 54 - 64) and 78 Peale's dolphins (95% CI= 65 - 95) in southern Chiloe, and 123 Peale's dolphins (95% CI= 97 - 156) in central Chiloe. An integrated precautionary approach to management is proposed based on scientific monitoring, environmental education in local schools, and public outreach to promote appropriate conservation strategies and ensure the dolphins' continued occupancy of important coastal habitat.
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Heithaus, Michael R. "Habitat use decisions by bottlenose dolphins (Tursiops aduncus) and tiger sharks (Galeocerdo cuvier) in a subtropical seagrass ecosystem." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ61648.pdf.
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Chen, Ing. "Population genetics of Risso's dolphins (Grampus griseus), Fraser's dolphins (Lagenodelphis hosei) and bottlenose dolphins (Tursiops spp.) in the North Pacific Ocean." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11590/.
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Cetaceans are highly mobile mammals, but many species still exhibit degrees of population structure while inhabiting seemingly boundary-free open waters. Resource specialisation is hypothesized as one of the main drivers of population structure. Using multiple diploid and haploid genetic markers, this study reveals, for the first time, the population genetic structure of Risso’s dolphins, Fraser’s dolphins and common bottlenose dolphins in the tropical-temperate regions of the western North Pacific Ocean. For the Risso’s dolphins, the results showed that there are at least three populations in the North Pacific Ocean, by-and-large parallel to the existing biogeographic provinces; and the direction of gene flow corresponds with the direction of the mainstream currents. Mitochondrial DNA (mtDNA) data showed that the Pacific populations are genetically different from the three populations in the eastern North Atlantic Ocean and the Mediterranean Sea. For the Fraser’s dolphins, the genetic differentiation between Japanese and Philippine waters is consistent with the differentiation suggested in an earlier skull morphometric study. For the common bottlenose dolphins, the results suggested that there are at least four populations in the western and central North Pacific Ocean, and the differentiation appears to correspond to habitat types, resembling the scenario of inshore-offshore differentiation seen in other populations of the same species in other regions. The analysis also confirmed that there is no evident gene flow between the two “sister species”, the common bottlenose dolphin and the Indo-Pacific bottlenose dolphin (T. aduncus), occurring sympatrically in the region. The mtDNA data suggested that the Risso’s and Fraser’s dolphin populations in the western North Pacific experienced an episode of expansion in the last 10,000 years. Genetic diversity is high in most of the population examined in this study; however, a relatively low effective population size is found in some populations and that may require further conservation attention.
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Brensing, Karsten. "Approaches to the behavior of dolphins Tursiops truncatus during unstructured swim with dolphin programs." [S.l. : s.n.], 2004. http://www.diss.fu-berlin.de/2004/164/index.html.
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Bishop, Amy Ruth. "Age, growth, reproduction and sexual dimorphism of the striped dolphin, Stenella coeruleoalba, off the south-east coast of southern Africa." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1011600.
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The striped dolphin, Stenella coeruleoalba, is an oceanic dolphin found worldwide in tropical to warm temperate waters. Globally populations are threatened through direct fishing, bycatch and pollution. Little is known about the life history of this species in South African waters and it is currently listed as ‘Data Deficient’ by the International Union for Conservation of Nature (IUCN). Critical to the conservation and management of this species is an understanding of basic life history parameters. For the present study, metadata and tissues from 101 stranded S. coeruleoalba along the south-east coast of southern Africa between 1969 and 2012 were analyzed to examine age and growth, male and female reproduction and sexual dimorphism. Age and growth were determined by counting the number of growth layer groups (GLG’s) present in their teeth. A von Bertalanffy growth curve gave the best fit to the data and indicated that physical maturity was reached around 21 years in males and 18 years in females. Additionally, asymptotic lengths were reached at 231cm and 224cm in males and females, respectively. The maximum ages obtained were 21 years for males and 20 years for females. Length at birth was estimated to be between 116cm and 119cm for males and between 112cm and 114cm for females. The reproductive status of the adult dolphins was assessed by histological and macroscopic analyses of gonadal tissue. Sexual maturity was attained before physical maturity in both sexes. The males reached sexual maturity between 8 and 12 years of age and between 209 and 224cm in total body length. The maximum combined testis weight comprised about 0.24% of the total body weight and sexual maturity was reached between a combined testis weight of 16 and 41g, a mean testis length of 8 and 10cm, and a mean seminiferous tubule diameter of 44 and 70μm. Females attained sexual maturity between 7 and 8 years of age and between 213 and 216 cm in total body length. The ovulation rate was 0.32 per year and the majority of ovulations occurred in the left ovary, with ovulations occurring in the right ovary only in individuals older than 10 years of age. The annual pregnancy rate was calculated to be 26%. Reproductive seasonality could not be established due to the small sample size and the absence of samples throughout the year. However, both conceptions and births appear to occur in both August and December/January. Additionally, testis weight and seminiferous tubule diameters appear to fluctuate throughout the year, which could suggest reproductive seasonality in this species. Sexual size dimorphism in mature adults was evident for a number of external measurements, however, sexual shape dimorphism was not present in this species. Mature males had significantly longer and wider pectoral fins, dorsal fins and flukes than females (p<0.05 in all cases). It was suggested that the larger appendages are required for male on male combat during intraspecific competition for females. Additionally, larger appendages aid in thermoregulation, propulsion and maneuverability. Females had a significantly greater distance between the tip upper jaw and the genital aperture and anus, which was expected due to differences in anatomy between male and female genital openings. Overall, S. coeruleoalba did not exhibit distinct sexual dimorphism and together with the relatively small testes in relation to the total body weight (0.24%) it was proposed that this species demonstrates a less extreme form of polygyny. Additionaly, the results of this study are important to the understanding of the basic biology of the species.
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Fortuna, Caterina Maria. "Ecology and conservation of bottlenose dolphins (Tursiops truncatus) in the north-eastern Adriatic Sea." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/157.
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Deutsch, Sierra Michelle. "Behavioral development of dusky dolphins." Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3084.
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Young, Deborah Dione. "Aspects of condition in captive and free-ranging dolphins." Thesis, Rhodes University, 1999. http://hdl.handle.net/10962/d1006117.
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Aspects of morphological and physiological condition of captive and net-caught dolphins were studied with respect to age, diet, reproduction and seasonal changes in environmental factors. These investigations aimed to provide base-line data on marine mammal physiological and morphological condition indices and to expand the knowledge of condition assessment of small cetaceans. By examining the interactive nature of animal condition and growth, diet and the environment, the study investigated the potential usefulness of animal condition indices to assess and monitor habitat quality. Base-line values for haematological and blood chemistry parameters were established for five captive bottlenose dolphins (Tursiops truncatus), using monthly blood samples, collected between 1992 and 1995, and corresponding measures of body weight and blubber thickness; feeding, dietary energy intake, water temperature and behavioural and medical records. Curves of best fit were used to interpret trends between leukocytic, haematological and blood chemistry parameters and morphology, diet and water temperature. WBC's and WBC differential cell types were related more distinctly to clinical changes in health, than to condition. RBC, HB and PCV were useful as short-term indicators of nutritional condition, with enhanced haematological status associated with greater food intake and improved diet quality. Weight was a more effective long-term indicator of nutritional status. The importance of blubber thickness measurements as a morphological index of condition was reinforced, with relationships between blubber thickness and haematology highlighting interactions between morphological and physiological condition. The complex interactions between haematology, diet, temperature and weight emphasised the need to account for all influential factors when considering haematological condition. The blood chemistry parameters of serum creatinine, BUN, BUN:creatinine and serum albumin provided the best indication of nutritional condition and diet quality in captive dolphins. Creatinine and BUN:creatinine also reflected changes in morphological condition. Reduced ALP was associated with nutritional stress but was more effectively used as an indication of metabolism and growth activity. LDH and CPK were highly variable and fluctuated with changing activity levels, limiting their use as condition indices. Serum sodium was an important indication of diet quality and hydration status. Many of these parameters effectively illustrated that physiological condition is compromised outside of the thermoneutral zone of the species. Bottlenose and common (Delphinus delphis) dolphins, incidentally caught in shark nets, were used to investigate the condition of free-ranging dolphins. Blood samples, taken as soon as possible after capture from drowned animals, were used to analyse physiological parameters. Dissections provided morphological data. Age and dietary status were assessed using growth layer groups in teeth and stomach content analyses, respectively. Morphological measures of net-caught dolphins reflected important interactions with diet, water temperature and reproductive status. Weight, girth and blubber thickness were valuable indicators of condition, although blubber thickness and proportional blubber weight were the best indicators of nutritional status. Condition of net-caught dolphins was difficult to assess in terms of leukocytic and haematological parameters. Stress- and post-mortem-associated changes, and variable data, reduced the usefulness of some parameters. WBC counts reflected on immunological status and served to emphasise changes in health, which may lead to deterioration in condition. WBC's showed potential as indicators of habitat quality, in terms of parasite load and/or pollution. Interactions between RBC, HB, PCV, MCV and dietary, morphological and environmental factors proved valuable in the short-term. Several haematological parameters were related to morphological condition, with weight, girth and blubber thickness, showing potential as non-invasive predictors of haematological status. Relationships between haematology and water temperature implied that dolphins have physiological and environmental "zones of comfort", within which condition is optimised. LDH and CPK were elevated by capture stress and post-mortem changes. Serum sodium and plasma glucose were good indicators of short-term nutritional status, but were altered by stress, which reduced their usefulness as condition indicators. BUN, albumin, globulin, albumin:globulin, total cholesterol and triglycerides appeared to be little affected by these changes and are potentially valuable indicators of condition in net-caught and/or free-ranging dolphins, particularly with respect to nutritional condition, and associated changes in morphology. Although data were limited, these parameters show the greatest potential as physiological indicators of animal condition and environmental health. The limitations of this study are recognised, however, results highlight the feasibility of using net-caught specimens to monitor the condition of free-ranging marine mammals, and the marine habitat as a whole. Relationships established in this study will be used to elucidate further on the interactive nature of marine mammal condition and aid in the development of a non-invasive condition assessment technique.
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Patroni, Jessica. "Visitor satisfaction with a beach-based wild dolphin tourism experience and attitudes to feeding wild dolphins." Thesis, Patroni, Jessica (2018) Visitor satisfaction with a beach-based wild dolphin tourism experience and attitudes to feeding wild dolphins. Honours thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/41944/.
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This research was conducted to gain insight into visitor’s satisfaction with a beach-based wild dolphin experience operated by the Dolphin Discovery Centre (DDC) on Koombana Beach, Bunbury, Western Australia and to understand visitor attitudes to the feeding of wild dolphins. Understanding visitor satisfaction and attitudes is important to wildlife tourism managers as it highlights areas of potential improvement for their operations with the goal of maintaining visitor satisfaction. To collect this information a pen and paper questionnaire was carried out to sample a cross section of visitors to Koombana Beach. Importance-Performance Analysis (IPA) was incorporated into the questionnaire and used as a measure of visitor satisfaction. This revealed that visitors to the DDC (n= 342) were satisfied with their experience at the DDC. However, there was an apparent barrier to people revisiting the DDC more than three times. The visitor satisfaction information was then examined at a finer scale to present aspects of the operation that have the potential for improvement to better meet visitor expectations. In regards to visitor awareness and attitudes to wild dolphin feeding, it was found that Koombana Beach visitors (n= 569) indicated a high awareness of the potential negative impacts of dolphin feeding and were against unregulated feeding of wild dolphins. There was also evidence to suggest that visitation to the DDC may discourage unregulated feeding and increase visitor knowledge in regard to wild dolphin feeding being illegal. This study reports the benefits of incorporating educational information into such wildlife experiences to assist in the reduction of harmful unregulated interactions. The results of this study reveal the importance of understanding visitor satisfaction and attitudes for wildlife tourism operations in order to foster repeat visitation as well as motivating others to visit. This work contributes to best practice dolphin tourism management by revealing that there is public support for the beach-based dolphin interaction provided and controlled by the DDC. This study also shows that visitors to Koombana Beach are likely to support actions that could reduce illegal dolphin feeding and injury from recreational boating.
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Smith-Goodwin, Jacqueline Anne. "A molecular genetic assessment of the population structure and variation in two inshore dolphin genera on the east coast of South Africa." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1004067.
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Coastal dolphins on the South African east coast are threatened by degradation and loss of habitat as a result of increasing coastal development, industrial effluent and agricultural runoff. In addition, dolphins off the coast of KwaZulu-Natal have, for more than four decades, been heavily exploited through unchecked incidental capture in shark nets set at 45 beaches. In light of the high rate of mortality and apparent depletion of both species, the persistence of bottlenose (Tursiops truncatus) and humpback (Sousa chinensis) dolphins in that region has been questioned. Genetic variation in south east African dolphin populations was determined as a means of assessing the fitness of the populations and their resilience to demographic disturbances. Furthermore, in order to determine the effects of continued mortality on the KwaZulu-Natal subpopulations, it was necessary to determine whether they are open or closed to immigration from the adjacent East Cape region, which represents a relatively unstressed region, characterised by a lack of shark nets and less intensive coastal activities. Genetic variation and differentiation in the maternal genome was assessed by determining the sequence of the first 400 bases of the mtDNA control region in bottlenose and humpback dolphins from KwaZulu-Natal and the East Cape. Nuclear variation and differentiation was estimated at six microsatellite loci and compared with earlier estimates determined from allozyme electrophoresis. Random amplified polymorphic DNA (RAPD) was assessed as a means of identifying population subdivisions and diagnostic population markers. Both bottlenose and humpback dolphins on the South African east coast are characterised by low nuclear and organellar genetic variation, consistent with a possible genetic bottleneck, the inferred date of which coincides with the onset of the last glacial period. Genetic variation in South African bottlenose dolphins was lower than that reported elsewhere for the species, while an intraspecific comparison supported lower genetic variation in South African humpback dolphins than in humpback dolphins sampled off Hong Kong. An analysis of molecular variance (AMOVA), performed on mtDNA haplotype frequency data indicated, for both species, significant genetic subdivision, concordant with geographic location. The data suggested female bottlenose dolphins demonstrate regional philopatry, displaying limited movement between KwaZulu-Natal and the East Cape. Female humpback dolphins tend towards strict local philopatry, with significant maternal differentiation evident both within and between regional subdivisions. Differentiation in microsatellite allele frequencies was also demonstrated between KwaZulu-Natal and the East Cape for both species, suggesting that the movement of male bottlenose and humpback dolphins may also be restricted. Nonetheless, considerably higher nuclear gene flow estimates suggested that males of both species represent the principal vectors of gene dispersal. The implications of historically low genetic variability and population subdivision in South African dolphins are important in view of the current rate of mortality in KwaZulu-Natal. The persistence of coastal dolphin populations relies on their ability to recover following a bottleneck event. Continued removal of demographically important age-sex classes such as occurs in shark nets, may not only further reduce the genetic variation, but would ultimately deplete dolphin populations in KwaZulu-Natal beyond a sustainable number, resulting in eventual local extinction. The differentiation of the two regions implies that, in the event of local extinction occurring, dolphins, particularly females, from adjacent regions will not readily re-colonise the area. This would result in fragmentation of the south east African populations and ensure reproductive isolation from neighbouring populations on the east African coast.
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Pearson, Heidi Christine. "Fission-fusion sociality in dusky dolphins (Lagenorhynchus obscurus), with comparisons to other dolphins and great apes." Texas A&M University, 2008. http://hdl.handle.net/1969.1/86073.
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I examined fission-fusion sociality in dusky dolphins (Lagenorhynchus obscurus), and investigated aspects of social convergence between dolphins and great apes. I used boat-based group focal follows and photo-identification to collect data in Admiralty Bay, New Zealand during 2005-2006. I used generalized estimating equations to examine relationships between party (group) size, rate of party fission-fusion, activity, and location; and relationships between leaping frequency and behavior. Using photo-identification images from 2001-2006, I analyzed the strength and temporal patterning of associations, short- and long-term association patterns, preferred/avoided associations, and behaviorally-specific preferred associations. To analyze social convergence between dolphins and great apes, I compared female bottlenose dolphin (Tursiops spp.) and chimpanzee (Pan troglodytes) social strategies through literature review.
I conducted 171 group focal follows, totaling 157 observation hours. Mean party size was 7.0±6.0 individuals. Party size changed every 5±.47.6 min on average. The most frequent activity was resting (37%), followed by traveling (29%), foraging (18%), and socializing (15%). Foraging was positively related to party size and rate of fission-fusion. Near mussel farms, foraging increased, traveling decreased, and rate of party fusion increased. "Clean" leaps were the most frequent leap type (84%) and were positively related to party size and foraging. Noisy and coordinated leaps were positively related to party size; noisy leaps were negatively related to foraging.
Associations during 2001-2006 (N = 228 individuals) were nonrandom for 125 days; associations within one field season were nonrandom for 60 days. Individuals formed preferred/avoided associations during most years. The strongest associations occurred during foraging and socializing; the weakest associations occurred during traveling. Individuals formed preferred associations during foraging, resting, and socializing.
Review of female bottlenose dolphin and chimpanzee sociality revealed that: 1) females form weaker bonds and are less social than males, 2) females associate mostly with other females, 3) mothers are often alone with their offspring, 4) mothers (vs. non-mothers) and non-cycling (vs. cycling) females associate less with males, and 5) non-cycling (vs. cycling) females occur in smaller parties. Female dolphins may be more social than female chimpanzees due to decreased scramble competition, increased predation risk, and decreased cost of transport for dolphins vs. chimpanzees.
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Fougères, Erin M. "Thermoregulation in bottlenose dolphins (Tursiops truncatus)." View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-1/r3/fougerese/erinfougeres.pdf.
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Elwen, Simon Harvey. "The distribution, movements and abundance of Heaviside's dolphins in the nearshore waters of the Western Cape, South Africa." Thesis, Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-01062009-151103/.
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Aeschlimann, Margaret (Peggy) Allie. "Mother-calf affiliations in captive bottlenose dolphins (Tursiops sp.) /." St. Lucia, Qld, 2000. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16517.pdf.
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Soldevilla, Melissa Sue. "Risso's and Pacific white-sided dolphins in the Southern California Bight using echolocation clicks to study dolphin ecology /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3324658.
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Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed November 14, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Bravo, Dubo Macarena Francisca. "Risso's dolphins of La Herradura, Coquombo, Chile." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50162767.
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The Risso’s dolphin (Grampus griseus G. Cuvier, 1812), one of the largest in the family Delphinidae, with groups ranging from a couple to over 80 individuals, can be found in temperate and tropical regions worldwide. They prefer waters 400 - 1000 meters deep and proximity of continental slopes. Their social structure was suggested to be based on age and sex, with strong bonds between adult males and between adult females. In Chile, prior to my research, there is only one publication on Risso’s dolphins; according to this report, they occur continuously along the Chilean coast.
La Herradura, a small and shallow bay, is located on the central-north coast of Chile, facing the Pacific Ocean. During a one year of study (April 2011 to April 2012), daily scans of the bay were conducted, covering the interior of La Herradura, and photo-identification boat surveys were undertaken within and outside the bay. In the course of this 1-year study, a total of 13 encounters were recorded outside the bay and 16 encounters inside the bay. The occurrence of Risso’s dolphin outside the bay did not show any clear pattern across the year. Dolphin groups encountered outside had a mean group size of 20 individuals (SD=19.5) and a median of 16. Of these groups, 38.5% had calves and the main behavior showed by the groups was travelling and foraging. Inside La Herradura bay, the groups of dolphins were seen primarily during the morning (8:00-12:00); this pattern was consistent across the study period. The mean group size was 63 individuals (SD=45.3) and a median of 46 individuals. The 87.5% of these groups had calves among them and the main behavior observed was milling.
A total of 747 individuals were photographically identified across 44 encounters and were used for mark-recapture analyses. Supplementary data, collected opportunistically between 2007 and 2010, provided by Mr. Oliver Yates, were included to increase the robustness of the analyses. Most of the individuals were sighted just once or twice during the 5-year period (2007-2012). The estimated size of the population generated by POPAN parametrization in program MARK was 3468 individuals (SE=188.5; 95% CI 3144 to 3889). Overall, Risso’s dolphin in the La Herradura area had very low site fidelity and the associations among individuals were generally weak (mean HWI=0.17 ±±SD=0.06). However, HWI picked at 0.2-0.3 and the results of principal coordinate analyses (5 clusters, modularity= 0.24) seem to indicate a grouping pattern that, although not rigorously tested due to the limitation of the sample size, might be indicative of preferential cluster-type associations within an overall fluid society.
Overall, in Coquimbo, Risso’s dolphin groups with calves seemed to use the La Herradura Bay as a resting site during the morning, probably after having spent the night foraging. The animals display typical fission-fusion dynamics. However, it is possible that the dolphins form a substantially more structured social grouping, which could only be tested with a longer study period and larger sample size.published_or_final_version
Biological Sciences
Master
Master of Philosophy
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Connelly, Paul R. "Passive acoustic tracking of divers and dolphins." Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/12883.
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This thesis describes work performed in the analysis and development of positioning algorithms for self-noise of a known kind; it also describes the development of short base-line systems capable of positioning the sources. Many studies of wild cetaceans rely on tracking the movement of wild animals, often in hostile conditions and with limited contact with these animals. Advanced technology exists for satellite or radio tracking of marine wildlife, but this relies on an animal being first caught and tagged. In situations where random interactions with marine wildlife are to be analysed, it is not practicable to attach devices to an animal, so it is appropriate to use passive techniques, in which the animal's self noise is located and tracked. Present passive systems usually include a long base-line array, which can be difficult to deploy. The problem may be overcome by reducing the array in size, but it results in an increase in positioning errors. This study attempts to quantifY these errors and looks into the practicability of short base-line passive arrays. Two systems are described here, both for tracking impulsive sounds in real time. The first is for use on pelagic trawl nets, the other as a prototype high-speed system to prove the different algorithms developed before and during this study. The prototype systems, each having a minimum of four receivers positioned in various configurations, have been tested in a tank with a controlled sound source. The source is a 'pinger', which allows the systems also to be adopted for diver positioning and tracking. A survey of unclassified literature has shown characteristics of cetacean acoustic signatures, which have been utilised in the optimisation of the systems. The physiology of cetaceans has also been reviewed to help understand the physical limitations of the systems presented.
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van, Geel Catherina Francisca (Nienke). "Predator movements in complex geography : spatial distribution and temporal occurrence of low-density bottlenose dolphin communities off western Scotland." Thesis, University of the Highlands and Islands, 2016. https://pure.uhi.ac.uk/portal/en/studentthesis/predator-movements-in-complex-geography(f898982a-6509-4e73-9340-b0ad7463ae6d).html.
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The coastal waters off western Scotland are inhabited by two small under-studied common bottlenose dolphin (Tursiops truncatus) communities: the Inner Hebrides and the Sound of Barra (SoB) community. The region is considered for future developments for the marine renewables industry, which have the potential to negatively impact these communities; however the assessment of impacts and the development of plans to minimise these are currently hampered by a lack of knowledge about the dolphin's distribution and residency patterns, and spatial and temporal mobility. Using a variety of research methods (dedicated cetacean surveys and targeted photo-ID trips, acoustic monitoring and the collection of opportunistic photo-ID and sightings data from the general public) the current study examined local dolphin spatial and temporal mobility patterns by investigation of their spatial distribution and temporal occurrence. Collectively, the results revealed the presence of two socially and geographically separated (at least 2006-2013) resident communities which both demonstrated year-round presence and long-term site-fidelity, but maintained different ranging patterns. Long-term presence of individuals from the Inner Hebrides community dated back to 2001 and dolphins from this community ranged widely in nearshore waters throughout the entire currently known communal range, and practically used the entire range throughout the year. The SoB community, on the other hand, appeared to have a more restricted distribution, and appeared female-dominated. Summer censuses of the SoB community revealed annual estimates of ≤15 dolphins, with four individuals first identified in 1995, and at least eight calves born since 2005. Acoustic presence of dolphins in the SoB varied through the year, and in relation to the tidal and diel cycles. This study demonstrated that the integration of complementary methodological approaches is useful in investigating mobility patterns of low-density populations, and given the indications for social and spatial isolation, these communities should be managed independently.
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Cipriano, Frank Walter. "Behavior and occurrence patterns, feeding ecology, and life history of dusky dolphins (Lagenorhynchus obscurus) off Kaikoura, New Zealand." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186097.
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My dissertation research focused on the behavior, movement patterns, and foraging ecology of dusky dolphins (Lagenorhynchus obscurus) off the east coast of New Zealand's South Island. Information on growth, morphometrics, parasites and life history was also collected. Movement patterns and foraging behavior of New Zealand dusky dolphins were much different from those of dusky dolphins observed off the Argentine coast by Bernd Wursig, the only other study of dusky dolphin behavior. Unlike the Argentine dolphins, which cooperatively herd anchovy to the surface and contain them there for feeding, New Zealand dusky dolphins behave and forage more like Hawaiian spinner dolphins (Stenella longirostris). In summer and fall, New Zealand dusky dolphins remain near shore in morning and early afternoon hours, then move into deeper water with greatly increased activity levels in late afternoon. In winter and spring they remain farther from shore at all times of day, are found in somewhat larger groups, and appear to travel along shore more often than in other seasons. In summer, dive times of radio-tagged dolphins also varied on a daily cycle, most long dives occurring during crepuscular and night periods. Stomach contents of incidentally-netted and beachcast dolphins contained primarily a demersal fish and a few types of mesopelagic fishes and squid. Acoustic surveys along the east coast of South Island show a dense layer of mesopelagic fishes and squid that move to within 50-100 m of the surface at night. Like Hawaiian spinners, New Zealand dusky dolphins feed primarily on prey in and associated with the vertically migrating layer, probably as a means of increasing foraging efficiency. External measurements of L. obscurus specimens were analyzed using canonical variate analysis, which revealed measurements useful in discrimination of age/sex classes, including dorsal fin dimensions, and positioning of dorsal fin and flipper insertions. Tooth-section age analysis of specimens allowed construction of growth curves; life span maximum was about 35 years. The very large size of active testes (over 1 kg each) during summer breeding represents a large proportion of total body weight. Along with observations of group composition variability, this suggests a promiscuous mating system and a fluid, extended-group social system.
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Borobia, Mônica. "Distribution and morphometrics of South American dolphins of the genus Sotalia." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61865.
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Serot, Julie Lynn. "Heavy metal analysis in Heaviside's dolphins (Cephalorhyncus heavisidii)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/193469.
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Skin and blubber tissue samples were collected from two hundred and six freeranging Heaviside’s dolphins (Cephalorhyncus heavisidii) during January through June of 2008, 2009, and 2010, along the coast of South Western Africa, to be analyzed for heavy metal concentration levels. Inductively coupled mass spectrometry (ICP-MS) was used to determine sample solution concentrations of all metals (aluminum, arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, nickel, selenium and zinc). Data provided by this thesis is the first reference of its kind for this species (Cephalorhyncus heavisidii), which is one of the least-known cetacean species in the world. In addition to baseline heavy metal concentration information for the Heaviside’s dolphin, meaningful population structural and ecological information was obtained. A level of site fidelity or specific movement pattern across certain sites was indicated by the presence of different concentration levels across individuals sampled in different areas, especially adjacent areas. With an investigation into the potential sources of the marine heavy metal contamination, it was deduced that these sources contributed to each site’s unique and characteristic toxicological and hydrological profile as reflected by the bioaccumulation patterns seen in this study. It was confirmed by this study that bioaccumulation levels are a meaningful and novel measure of population structure. Potential evidence of differences in bioaccumulation patterns between sexes was observed in this study, as well. Although not definitive, a difference in metabolism, heavy metal elimination, or ranging pattern between males and females was suggested by the results. Variation in the results suggests a deepened level of complexity in the physiological and ecological aspects of trace elements accumulation and detoxification in the tissue of an apex predator like the Heaviside’s dolphin. Finally, a general assessment of health implications for the species was established, and it was found that Heaviside’s dolphins have higher than average mammalian trace element concentrations, and higher than average concentrations as specifically compared with other odontocetes. Further research using a larger sample size and using internal organs will provide more insight and a deeper understanding of the novel information presented here.published_or_final_version
Biological Sciences
Master
Master of Philosophy
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Heflin, Ashley Shew. "What Dolphins Want: Animal Intentionality and Tool-Use." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/31748.
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In this thesis, I argue that at least some animals have the sort of intentionality philosophers traditionally have only ascribed to humans. I argue for this through the examination of tool-use among New Caledonian crows and Bottlenose dolphins. New Caledonian crows demonstrate advanced tool-manufacture and standardization, while Bottlenose dolphins use social learning to a much greater degree than other animals. These two case studies fit nicely with many of the non-linguistic accounts of intentionality employed by philosophers.
This thesis is aimed at showing that our basic philosophical concept of intentionality leaves room for intentional behavior on the part of non-human animals. Descriptions of human behavior are often contrasted with that of â lowerâ animals. Many have taken rationality as the characteristic that separates us from animals, and our notions about the superiority of humans have been passed down through theology and philosophy. From Plato onward, philosophers have created divisions that put humanity in a special position relative to all other creatures. Neglecting a careful analysis of animal behavior in making these divisions does a disservice not only to the animals themselves, but also to humans. This thesis is an attempt to start pulling a thread of the discussion about the specialness of humans out for examination. Specifically, I examine the case of intentionality in the framework of the tool-related behaviors of crows and dolphins.
Master of Arts
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Hanf, Daniella. "Species Distribution Modelling of Western Pilbara Inshore Dolphins." Thesis, Hanf, Daniella (2015) Species Distribution Modelling of Western Pilbara Inshore Dolphins. Masters by Research thesis, Murdoch University, 2015. https://researchrepository.murdoch.edu.au/id/eprint/29205/.
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This thesis presents the first insights into inshore dolphin distribution of the western Pilbara. The region is undergoing rapid coastal development, which has the potential to threaten Indo-Pacific bottlenose dolphin (Tursiops aduncus) and Australian humpback dolphin (Sousa sahulensis) populations. Understanding the distribution of these species is essential for their conservation.
Species distribution models (SDMs) were developed using dolphin sightings data that were opportunistically collected during dugong aerial surveys. A geographical information system (GIS) was used to generate the training data, which consisted of the binomial presence-absence of dolphins, distances from mainland and islands, sea surface temperature (SST), ocean fronts and bathymetric derivatives. Preliminary models were developed using generalised additive model (GAM) and component-wise boosting techniques. Models could not be fit to the data using either technique. It was unclear whether this was a result of relatively few dolphin sightings across a large study area, pseudo-absences, weak environmental variables, or a combination of all of these factors. Maximum Entropy (MaxEnt) software was subsequently used as an alternative modelling technique to model the presence of dolphins, along with automatically generated background data, in order to avoid problems associated with unreliable absence data.
Bottlenose and humpback dolphins were sympatric, with overlap in occurrence across the study area. Bottlenose dolphin presence was associated with the slope at the 20 m contour and waters around the Muiron Islands. This is likely to be a productive area that could be important for foraging. Humpback dolphin presence was associated with intertidal areas, including shallow coastal waters near the mainland and surrounding islands. The presence of numerous offshore islands would thus explain why humpback dolphins were recorded more than 50 km from the coastline.
MaxEnt models were limited in their predictive power. Dedicated aerial surveys for inshore dolphins, using standardised techniques, are required to obtain reliable species data. In addition to increasing the sample size available for modelling, greater certainty in group size and composition could allow count, calf and mixed species group data to be modelled. Adequate species conservation needs to incorporate various ecological processes that occur at different spatial and temporal scales. Guidance is provided for undertaking boat-based studies and biopsy sampling, gathering opportunistic sightings data, and undertaking satellite telemetry research in addition to dedicated aerial surveys.
Distribution modelling for inshore dolphins of northern WA is an intrinsically challenging research project, due to limited habitat data and the elusive nature of the subject species, particularly humpback dolphins. This research has obtained the first insights into the distribution of inshore dolphins in northern WA. Through lessons learnt, this research has paved the way for the development of future models to have a greater predictive ability, which will be useful for the conservation of threatened inshore dolphin species.
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West, Kristi Lee. "Ecology and biology of the rough-toothed dolphin (Steno bredanensis)." Thesis, University of Hawaii at Manoa, 2002. http://hdl.handle.net/10125/990.
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Greater knowledge of the rough-toothed dolphin, Steno bredanensis, is needed to effectively contribute to conservation and management efforts for this species. The primary purpose of this research was to describe ecological and biological parameters for S. bredanensis that will be useful in future assessments of population stress. Several approaches were used to study S. bredanensis, including investigations of free-ranging populations, dead specimens, and captive individuals. Free-ranging rough-toothed dolphins distributed near small oceanic island environments were found to be more commonly sighted in-shore than off-shore. In the Windward islands of French Polynesia, this species preferred water depths of 1000 to 2000m and a distance of 1.8 to 5.5 km from the barrier reef. Group sizes ofrough-toothed dolphins sighted in French Polynesia range between 1 and 35 individuals with a mean size of 12.1. Endocrinology data for S. bredanensis was established in captive healthy and stranded individuals. Ranges and means were provided for progesterone, testosterone, cortisol and thyroid hormones. Changes in thyroid hormone concentrations were reflective of health status and testosterone appeared to be suppressed in ill individuals. Reproduction in S. bredanensis was investigated by determining the size and age range that this species attains sexual and physical maturity. Female rough-toothed dolphins attain sexual maturity by 9 to 10 years of age and males between 5 and 10 years at a similar length of approximately 216 cm. Physical maturity is generally reached at an older age and larger size for both males and
females. Ecologically healthy and unheahhy populations of S. bredanensis were described in this investigation and these fmding will be useful in assessing future threats to this species.
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Islas, Valentina. "Genetic characterisation and social structure of the East Scotland population of bottlenose dolphins (Tursiops truncatus)." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/1002.
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The Eastern Scottish population of bottlenose dolphins (Tursiops truncatus) is the northernmost population of this species. The resident core of this population consists of 120 to 150 different individuals. This small size and its geographical isolation from other populations raises questions about its viability and whether the population has behavioural patterns that differ from those common to other populations of the same species. Microsatellite genetic diversity was low and mitochondrial DNA genetic diversity values were lowest in East Scotland compared to other populations worldwide and to neighbouring populations around UK waters. It has been well documented, from four different field sites worldwide, that male bottlenose dolphins form alliances with preferred male associates. These alliances can last for several years and the males involved show association coefficients similar to those of mothers and calves (0.8-1.0). These alliances appear to be of great importance in obtaining matings for the males. In the Eastern Scottish population males do not form alliances. No evidence of strong associations between individuals of either sex was found and there was no correlation between association and relatedness patterns. I suggest that the isolation and small size of the population together with reduced genetic diversity affects the pressure of kin selection for altruistic behaviours. There is no gain in competing or associating with close relatives for access to mates and it might be more important to avoid inbreeding by dispersing. Although evidence of gene flow between East Scotland and its neighbouring populations was not confirmed with Bayesian clustering analysis, a small set of individuals from Wales were found to be closely related to individuals from the East Coast of Scotland. In general the dynamics found in UK water populations resemble those of the Western North Atlantic with sympatric populations of coastal as well as pelagic individuals.
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Silva, Monica Almeida. "Population biology of bottlenose dolphins in the Azores archipelago." Thesis, University of St Andrews, 2007. http://hdl.handle.net/10023/215.
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The ranging behaviour, habitat preferences, genetic structure, and demographic parameters of bottlenose dolphins living in the Azores were studied using data collected from 1999 to 2004. Only 44 dolphins out of 966 identified were frequently sighted within and between years and showed strong site fidelity. The remaining individuals were either temporary migrants from within or outside the archipelago, or transients. Estimates of home range size were three times larger than previously reported for this species, possibly as a result of the lower availability of food resources. Mitochondrial DNA sequences showed very high gene and nucleotide diversity. There was no evidence of population structuring within the Azores. The Azorean population was not differentiated from the pelagic population of the Northwest Atlantic, suggesting the "unproductive" waters of the Atlantic do not constitute a barrier to dispersal. Population size, survival and temporary emigration rates were estimated using open-population models and Pollock's robust design. A few hundreds of dolphins occur in the area on a given year, though the majority should use it temporarily, as suggested by the high emigration rates. Bottlenose dolphins preferentially used shallow areas with high bottom relief. Temporal and spatial persistence of dolphin-habitat associations documented in this study further supports the idea of a close relationship between certain bathymetric features and important hydrographic processes and suggests the occurrence of prey aggregations over these areas may be, to some extent, predictable. Several results of this study suggest there are no reasons for concern about the status of this population. Yet, the resident group may be negatively affected by increasing pressure from the whale watching activity. Although the proposed Marine Park constitutes important habitat for resident dolphins, at present, the area is clearly insufficient to satisfy their spatial requirements and its conservation value may be limited.
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Currey, Rohan J. C., and n/a. "Conservation biology of bottlenose dolphins in Fiordland, New Zealand." University of Otago. Department of Marine Science, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090730.141243.
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The bottlenose dolphins of Fiordland, New Zealand, live at the southern limit of the species' worldwide range. They are exposed to impacts from tourism and habitat modification, particularly in Doubtful Sound, and their conservation requirements are presently unclear. Dolphin abundance was estimated in Doubtful Sound using photo-identification census and capture-recapture techniques (56 individuals; 95% CI: 55-57), detecting a decline of 34-39% over 12 years among adults and sub-adults (>3 years old). The cause of this decline was investigated via demographic modelling in Doubtful Sound and a comparative assessment of population status in Dusky Sound.
Capture-recapture modelling of photo-identification data compiled since 1990 yielded a constant adult survival rate marginally lower than prior estimates for wild bottlenose dolphins ([phi]a(1990-2008) = 0.9374; 95% CI: 0.9170-0.9530). Survival of calves (<1 year old) declined to an unsustainable level that is thought to be the lowest recorded for wild bottlenose dolphins ([phi]c(2002-2008) = 0.3750; 95% CI: 0.2080-0.5782) coincident with the opening of a second tailrace tunnel for a hydroelectric power station. Reverse-time capture-recapture modelling detected declines in recruitment (f(1994-2008) = 0.0249; 95% CI: 0.0174-0.0324) and population growth ([lambda](1994-2008) = 0.9650; 95% CI: 0.9554-0.9746) over time consistent with the decline in calf survival (<1 year old) and a separate reduction in juvenile survival (1 to 3 years old) reflecting cumulative impacts.
Dolphin abundance was estimated in Dusky Sound using photo-identification census and capture-recapture techniques (102 individuals, 95% CI: 100-104) providing no evidence of interchange with Doubtful Sound. A comparative assessment of health status between Doubtful and Dusky Sounds revealed skin lesioning was more severe in Doubtful Sound, particularly among females, and newborn calves appeared to be smaller and were born over a shorter period: factors that may contribute to the low levels of calf survival in Doubtful Sound. The Fiordland bottlenose dolphins were assessed under IUCN Red List regional criteria. The small size of the population (205 individuals, 95% CI: 192-219) combined with the projected rate of decline in stochastic matrix models (average decline 31.4% over one generation) resulted in a recommended classification of Critically Endangered.
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Silva, Mónica Almeida e. "Population biology of bottlenose dolphins in the Azores archipelago." St Andrews : University of St Andrews thesis, 2007. https://research-repository.st-andrews.ac.uk/handle/10023/215.
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Slooten, Elisabeth. "Population biology, social organization and behaviour of Hector's Dolphins." Thesis, University of Canterbury. Zoology, 1990. http://hdl.handle.net/10092/5800.
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Hector's dolphins are threatened with local extinction by entanglement in coastal gillnets. This thesis provides data on population biology, social organization and behaviour of Hector's dolphins that help assess human impacts on their populations. To estimate population growth, I integrated anatomical studies which estimated longevity and age at first reproduction, with photographic field studies which estimated reproductive rate and survival rate. Sixty incidentally caught and beach-cast dolphins were aged from the growth layers in their teeth. Maximum age was 19 years for females and 20 for males. Females gave birth to their first calf at 7 to 9 years old, and thereafter had one calf every 2 to 3 years. Population models using these data predicted maximum population growth rates of 1.8 to 4.4% per year. These rates were exceeded by the number of Hector's dolphins recently killed in gillnets in the Pegasus Bay-Canterbury Bight area. Survival rates (including gillnet mortality) estimated using photographic identification, also suggested that this population was unable to cope with recent gillnet entanglement levels. Population models using these survival rates (0.797 to 0.865 after the first year of life), even in combination with the most optimistic reproductive rates, resulted in a decreasing population. The population models were also used to explore the likely consequences of management strategies which reduce entanglement mortality. Population and population growth rate fluctuated markedly for several decades after a significant reduction in entanglement mortality, especially if the age structure of the population was biased towards younger individuals.
A study of social organization and behaviour pointed to another potential conservation risk. The social organization of Hector's dolphins was studied using photographic identification. Each individual associated loosely with a relatively large number of others, rather than with a few close associates, and groups frequently joined other groups and exchanged members. Sequence analysis was used to classify Hector's dolphin behaviour into five categories: 'feeding', 'sexual" 'aggressive', 'play' and 'aerial', using behaviour sequence analysis. The number of sexual behaviours per individual was highest in groups of 11-15 dolphins, and tended to increase after groups came together. The fluid association patterns and increase in sexual behaviours after groups come together suggest that Hector's dolphins have a promiscuous mating system in which males search for rather than monopolize females. Such a mating system has the potential to reduce fertilization rates in areas of low abundance.
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Esch, H. Carter. "Whistles as potential indicators of stress in bottlenose dolphins (Tursiops truncatus) /." Electronic version (PDF), 2006. http://dl.uncw.edu/etd/2006/eschh/hcarteresch.pdf.
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Rames, Arielle Elizabeth. "Playing with Dolphins and Calling It Research| A Mixed-Methods Study Investigating Human Emotional Well-Being and Experiential Responses to Interacting with Dolphins." Thesis, Sofia University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10237439.
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This study will help to clarify how interactions with dolphins affect people. It examines human well-being and experiential responses to scuba diving with bottlenose dolphins, Tursiops truncatus, and compares this to participation in a scuba dive without this interaction. Ninety-nine adults were split between an intervention and a control group in a mixed methods convergent parallel quasi-experimental design. Before and after the activity participants completed an emotional well-being scale (Positive and Negative Affect Schedule; PANAS) and only afterward received a researcher-designed qualitative questionnaire targeting peak experiences. For the PANAS, a t-test found a significant difference in negative affect change scores between groups, t(97) = –2.135, p = .035, d = 0.43. The intervention group experienced a larger decrease in negative affect than the control group at a small-medium effect size. Qualitative themes endorsed more by the control group are self-confidence; level of difficulty; novelty; transformation or overcoming; nature; and physical, mental, or emotional stress or discomfort. For the intervention group, more participants expressed tranquility; numinosity; and connection to nature, themselves, or the Divine. Themes mentioned approximately equally include ineffability, presence in the moment, comfort and safety, desiring to continue, good or extraordinary experience, and freedom. Twelve intervention and 9 control group participants appeared to have a peak experience, as defined by Maslow. This indicates that a peak experience during a scuba dive, with and without dolphins, is a relatively common occurrence. This study demonstrates the importance of rigorous studies in human-dolphin interaction research. Studies on human-dolphin interaction published to date have neglected to impose appropriate controls, which has led to the misattribution of all pre- to postintervention differences to dolphin interaction. Both groups have intriguing results; the presence of dolphins led to a larger decrease in negative affect and greater likelihood of tranquility, numinosity, connection, and peak experiences.
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Gray, Howard Willem Ian. "Phylogeography and population structure in highly mobile marine taxa in the western Indian Ocean : bottlenose dolphins (Tursiops spp.) and common dolphins (Delphinus sp.)." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11542/.
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In the marine environment, where barriers to dispersal are limited, taxa normally exhibit genetic homogeneity across large spatial scales. Extraordinarily, marine mammals regularly exhibit genetic differentiation within their cruising range. Furthermore, recent radiation in Delphininae has resulted in several closely related species that remain taxonomically unresolved, particularly bottlenose dolphins (BND) Tursiops spp. and common dolphins (CD) Delphinus spp., making these taxa interesting for studying evolutionary processes. Using mitogenomes and a multi-locus dataset, BNDs from the northwest Indian Ocean (IO) were compared with other recognized species/ecotypes around the world. A new (third) lineage of Indo-Pacific BND, T. aduncus, was identified from the region. Reconstructions of ancestral biogeography and divergence date estimates, suggest a divergence mechanism within T. aduncus that coincides with climate change over the Pleistocene. Reconstructions of ancestral morphology suggest a coastal ancestry for BNDs. Significant population structure was exhibited between T. aduncus populations in the western IO based on mtDNA control region sequences and 14 microsatellite loci. Genetic subdivision appears to correlate with habitat heterogeneity across the study area, which may be driving differentiation through local adaption. Traditional and geometric morphometric techniques were used to investigate congruency between genetic and phenotypic differentiation of three BND lineages in the northwest IO. Strong differences were exhibited in morphology between common BNDs, T. truncatus, and T. aduncus. The T. aduncus lineages were similar, however significant differences in morphology were evident. Significant genetic structure was evident between CD populations off Portugal, South Africa and Oman, based on mtDNA sequences and 14 microsatellites. Further analyses support the taxonomic designation of D. capensis tropicalis in the northwest IO. Both genera exhibit significant population structure over spatial scales outdistanced by their dispersal abilities. Contemporary and historic environmental heterogeneity are suggested as drivers for this structure. Further evidence is provided for the northwest/northern IO as a region of evolutionary endemism, which will inform regional conservation initiatives.
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Weir, Caroline R. "Ecology and conservation of cetaceans in the waters between Angola and the Gulf of Guinea, with focus on the Atlantic humpback dolphin (Sousa teuszii)." Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=167802.
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Part one of this thesis examined the tropical oceanic cetacean community occurring between Togo and Angola (6°N-11°S latitude). Twenty-two cetacean species were recorded during 5905.3 hr of dedicated survey effort from platforms of opportunity between 2004 and 2009. Sperm whales (Physeter macrocephalus) and humpback whales (Megaptera novaeangliae) were the most frequently-sighted species, and exhibited significant differences in occurrence related to water depth and survey month. Five species inhabited both neritic and oceanic waters, while the remainder were exclusively oceanic. The habitat preferences and niches (based on depth, seabed slope, sea surface temperature (SST) and frontal strength) of eight species were examined using classification trees and a principle component analysis. Water depth and SST appeared to be the primary variables (of those examined) explaining the presence of most species. Part two of the thesis was a study of the Atlantic humpback dolphin (Sousa teuszii), a species endemic to nearshore eastern tropical Atlantic (ETA) waters. A total of 1,626.8 km of boat- and vehicle-based effort in Namibe Province during 2008, produced 52 S. teuszii sightings. Further sightings were recorded during 53.7 hr of shore-effort at Flamingos (n=6) and opportunistically (n=13). Ten individuals were photo-identified. Multiple resightings (and an absence of unmarked animals) indicated low abundance, high site fidelity and year-round occurrence. Sousa teuszii produced simple (85% had a single inflection point) whistles in the 2.5-23.4 kHz fundamental frequency range and broadband click trains with repetition rates varying from 5.8-250.8 clicks/s. The implications of the findings for the future monitoring and conservation of cetaceans in the ETA are discussed.
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Dye, David C. "High frequency sonar components of normal and hearing impaired dolphins." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA384477.
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Thesis (M.S. in Physical Oceanography) Naval Postgraduate School, Sept. 2000.Thesis advisor(s): Muir, Thomas G.; Chiu, Ching-Sang. Includes bibliographical references (p. 69-70). Also available online.
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Sasaki, Yukiko. "Studies on wild river dolphins by stationed passive acoustic methods." 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/175158.
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Fripp, Deborah 1970. "Techniques for studying vocal learning in bottlenose dolphins, Tursiops truncatus." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85610.
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Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 1999.Vita.
Includes bibliographical references.
by Deborah Redish Fripp.
Ph.D.
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Lopez, Marulanda Juliana. "Acoustic Communication and Social Behavior in Bottlenose Dolphins (Tursiops truncatus)." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS016/document.
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Les grands dauphins sont des cétacés sociaux qui se servent principalement du canal acoustique pour communiquer sur de longues distances ou dans des habitats dont la visibilité est limitée. Il y a un manque général d’information concernant l’utilisation de cettecommunication acoustique au sein de son groupe social. Cependant, la production vocale des grands dauphins comprend des sifflements, des clics et des sons pulsés en rafale, avec certains sifflements appelés « signatures sifflées » qui pourraient être utilisés pour s’adresser les uns aux autres. Au cours de cette thèse, nous avons développé un système facilement déployable qui identifie l'animal produisant le son et permet des observations comportementales sous-marines simultanées. Nous avons testé cette méthodologie avec des grands dauphins en liberté et en captivité. La présente thèse de doctorat vise à mieux comprendre la communication des grands dauphins au sein de leur groupe social. D'abord, j'ai développé deux études visant à décrire comment l'activité vocale des dauphins captifs varie en relation avec le comportement et l'interaction avec les humains. Deuxièmement, je présente la conception et la mise en oeuvre d'une méthodologie innovante (système BaBeL) qui permet la localisation du dauphin vocalisant dans un environnement tridimensionnel, et qui peut être utilisé en captivité et avec des dauphins en liberté. Enfin, je présente deux applications de cette méthodologie de localisation pour aborder des questions de recherche concernant le comportement exploratoire d'une jeune dauphin et l'utilisation de vocalisations pour des mouvements coordonnés chez les grands dauphinsBottlenose dolphins are highly social cetaceans that strongly rely on acoustic communication and signaling. The diversity of sounds emitted by the species has been structurally classified in whistles, clicks and burst-pulsed sounds, with some whistles called « signature whistles » that are used as cohesion calls. During this thesis, we developed an easily deployable system that identifies the animal producing sound and allows simultaneous underwater behavioral observations. We tested this methodology with bottlenose dolphins infreedom and in captivity. The present doctoral thesis aims to better understand the communication of bottlenose dolphins within their social group. First, I developed two studies to describe how the signature and non-signature whistle rate of captive dolphins varies in relation to behavior and interaction with humans. Secondly, I present the design and implementation of an innovative methodology (BaBeL system) that allows the localization of vocalizing dolphins in a three-dimensional environment, and which can be used in captivity and with free-range dolphins. Finally, I present two applications of this location methodology to address research questions regarding the exploratory behavior of a young dolphin and the use of vocalizations for coordinated movements in bottlenose dolphins
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Marley, Sarah Anne. "Behavioural and Acoustical Responses of Coastal Dolphins to Noisy Environments." Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/56484.
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This thesis aimed to examine the behavioural and acoustical responses of coastal dolphins to noisy environments. A combination of monitoring techniques were employed, in the form of land-based theodolite-tracking and autonomous underwater acoustic recorders. First, the soundscape of dolphin habitats was described to identify prominent sound sources and spatio-temporal patterns. Dolphin responses to the most ubiquitous anthropogenic sound source – vessel traffic – were then assessed, revealing alterations to movement speeds, behavioural budgets, and whistle characteristics.
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Nolte, Zianca. "The natural history of the humpback dolphin, Sousa chinensis, in KwaZulu-Natal, South Africa : age, growth and reproduction." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013178.
Full textAbstract:
Globally, inshore cetaceans are being threatened by a number of anthropogenic activities. The Indo-Pacific humpback dolphin, Sousa chinensis, is currently listed as ‘near threatened’ by the International Union for the Conservation of Nature (IUCN). In order to be able to advise on management and conservation strategies, knowledge on the life history of the species is required. To date very little is known about the biology of humpback dolphins. The aim of the present study was to determine basic life history parameters, including age, growth and reproduction of humpback dolphins incidentally caught in shark nets. Age was estimated by counting the growth layer groups (GLGs) in the dentine and cementum of sectioned and stained teeth. Both a Von Bertalanffy and a Gompertz growth curve fitted well to the data, but for comparison with previous studies on Sousa, the Gompertz growth function was adopted to describe the relationship between length and age for KwaZulu-Natal populations. Length at birth was estimated between 104.33 and 111.57 cm for males and females, respectively. Asymptotic length was reached at 266.48 cm and 239.29 cm for males and females, respectively. This corresponds to the attainment of physical maturity at 24 GLGs in males and 16 GLGs in females. Asymptotic mass for males could not be determined, while for females it occurred around 160 kg. The maximum age estimates and recorded lengths were 24 GLGs and 279 cm for males and 17.7 GLGs and 249 cm for females. Differences in length-at-age and mass-at-age for S. chinensis suggest sexual dimorphism. The attainment of sexual maturity in males occurred between 9 and 10 GLGs, corresponding to 230 cm total body length and 140 kg. The maximum combined testis mass of mature males comprised 0.42% of total body mass, and a roving male mating system was proposed. In females, sexual maturity occurred around 7.6 GLG, between 220 and 222 cm and 104 - 140 kg. The ovulation rate is estimated at 0.2 ovulations per annum, suggesting a calving interval of five years. It is evident from the results obtained in the present study that geographical differences exist in the life history parameters of S. chinensis. As a result, regional conservation and management strategies are imperative. Results from this study can therefore assist in assessing the status of existing population structures in the KwaZulu-Natal coastal waters, and the implementation of regional mitigation strategies to ensure the continued survival of humpback dolphins in the region.
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Elsberry, Wesley Royce. "Interrelationships between intranarial pressure and biosonar clicks in bottlenose dolphins (Tursiops truncatus)." Texas A&M University, 2003. http://hdl.handle.net/1969.1/554.
Full textAbstract:
Recent advances in technology permitted the first simultaneous digital recording
of intranarial pressure and on-axis acoustic data from bottlenose dolphins during a
biosonar target recognition task. Analysis of pressurization events in the intranarial
space quantifies and supports earlier work, confirming that intranarial pressure
is increased when whistle vocalizations are emitted. The results show complex relationships
between various properties of the biosonar click to the intranarial pressure
difference at the time it was generated. The intranarial pressure that drives the production
of clicks is not the primary determinant of many of the acoustic properties
of those clicks. A simple piston-cylinder physical model coupled with a sound production
model of clicks produced at the monkey-lips/dorsal bursae complex yields an
estimate of mechanical work for individual pressurization events. Individual pressurization
events are typically associated with a single click train. Mechanical work for
an average pressurization event is estimated at 10 Joules.
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Kr??tzen, Michael Christian School of Biological Earth & Environmental Sciences UNSW. "Molecular Relatedness, Paternity and Male Alliances in Bottlenose Dolphins (Tursiops sp.) in Shark Bay, Western Australia." Awarded by:University of New South Wales. School of Biological, Earth and Environmental Sciences, 2002. http://handle.unsw.edu.au/1959.4/19230.
Full textAbstract:
Male bottlenose dolphins (Tursiops sp.) in Shark Bay, WA, form several levels of alliances. Determining the relationship between paternity, relatedness and alliance membership is crucial in seeking evolutionary adaptive explanations for alliance formation. Previous behavioural data have revealed a social system whose complexity is unparalleled outside humans. Pairs or trios of male dolphins cooperate as stable first-order (1? alliances to sequester and control reproductive females. Two 1?alliances sometimes cooperate as small second-order (2? alliances to attack other 1?alliances or defend against attacks. Some males choose a different strategy by forming large superalliances of approximately fourteen individuals to attack 1?and 2?alliances. Kinship appears to play a role in the structuring of male alliances, but its importance differs with the alliance type. Relatedness analyses showed that on average, males in 1?and 2?alliances are strongly related, while members of the superalliance are not. Further, the strength of the association of partners within the superalliance was not correlated with their genetic relatedness. Thus, within one sex, it appears that there may be more than one simultaneous mode of group formation and its evolution. There was also an association between alliance behaviour and reproductive success as predicted by some theories of group formation. I assigned nine paternities to six out of 107 mature males. Males with alliance partners were significantly more successful in fathering offspring than males without partners. Compared to non-allied males, the chance of obtaining a paternity was significantly higher for members of 1?alliances, and reproductive success was significantly skewed among 1?alliance members. Assessment of kinship and relatedness required a number of technical developments and some preliminary data. I first refined a biopsy system in order to obtain tissue samples from free-ranging dolphins with minimum behavioural effects irrespective of age-group or gender. Then I carried out population genetics analyses, which demonstrated that there was only weak population structure within Shark Bay. Microsatellites showed a weak pattern of isolation by distance, and eight haplotypes of the mitochondrial DNA control region suggested weak female philopatry. The high number of migrants between locations allowed all samples from East Shark Bay to be pooled for subsequent analyses.
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Nicholson, Krista. "Dolphins as part of the ecological character of Ramsar-listed wetlands: A case study of Indo-Pacific bottlenose dolphins in the Peel-Harvey Estuary, Western Australia." Thesis, Nicholson, Krista (2021) Dolphins as part of the ecological character of Ramsar-listed wetlands: A case study of Indo-Pacific bottlenose dolphins in the Peel-Harvey Estuary, Western Australia. PhD thesis, Murdoch University, 2021. https://researchrepository.murdoch.edu.au/id/eprint/62546/.
Full textAbstract:
Whether dolphins are part of the ecological character of Ramsar-listed wetlands depends on their status as a biological component of the ecosystem (e.g., dolphin biomass, residency) and their involvement in ecosystem processes (e.g., energy and nutrient dynamics, species interactions). The aim of this thesis is to provide the scientific basis for deciding whether Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the Peel-Harvey Estuary (PHE) in Western Australia should be considered part of the ecological character of the Ramsar-listed Peel-Yalgorup wetland system that the PHE is a part of. Dolphin photo-identification and behavioral data, as well as tissue samples, were collected during boat-based surveys in the PHE and adjacent coastal waters between 2016 and 2019. Social, spatial and isotopic (δ13C and δ15N) niche partitioning were investigated to identify population structure based on biologically meaningful criteria. Social structure, home range and stable isotope analyses confirmed a year-round resident, socially, spatially and isotopically distinct community of ~90 dolphins occupying the PHE. The estuarine community had a slightly negative population growth rate (-0.004, SD 0.062) with a low probability (0.010, SE 0.003) of extinction in 100 years. The community was closed to immigration, with changes in abundance driven by births and deaths and likely permanent emigration of immature males. Social clusters within the community were heterogeneous in their space use and diet. Detritivores, omnivores and herbivores and benthic omnivores and carnivores each contributed approximately a third and water column species 10%, to the annual fish biomass (~200,000 kg) removed by the resident dolphin community. The findings of this thesis provide strong empirical evidence that dolphins are functional biological components of the ecological character of the Peel-Yalgorup Ramsar site.
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Lam, Hung Helina. "Whale and dolphin watching : should dolphin watching in Hong Kong be regulated? /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22266331.
Full text
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Shelton, Deborah Ellen. "Dusky dolphins in New Zealand: group structure by sex and relatedness." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4970.
Full textAbstract:
The sex of and genetic relatedness among interacting individuals are known to be
biologically fundamental features that characterize the composition of animal groups.
Current work continues to illuminate reasons for the variety of animal social patterns,
including patterns in group membership. I investigated the composition of dusky
dolphin groups relative to sex and relatedness at two locations in New Zealand. In
Kaikoura, dusky dolphins are found year-round, foraging nocturnally on verticallymigrating
prey and socializing in distinct group types (mating, nursery, and adult) during
the day. By contrast, dusky dolphins use Admiralty Bay, where they feed diurnally on
small schooling fishes, primarily in the winter. Molecular sexing revealed the sex of 107
dusky dolphins. The Kaikoura data support previous findings that small mating groups
consist mostly of males and indicate that small adult groups can consist of either or both
sexes. In Admiralty Bay, the percentage of female dolphins present during the study
was estimated to be only 7.4%âÂÂ22.2% (95% confidence interval, n=88). A
randomization test further indicates that dusky dolphins in Admiralty Bay grouped
preferentially with same-sex individuals. Nuclear and mitochondrial markers were used
to investigate patterns of relatedness. Dusky dolphins sampled in Kaikoura (n=17) and
Admiralty Bay (n=47) were genotyped at seven microsatellite loci, and genetic
relatedness among all genotyped pairs was estimated. A randomization test indicates
that dusky dolphins did not group preferentially by relatedness in Admiralty Bay.
Grouping history for 13 genotyped samples was also known from a multi-year
photographic record of individually distinctive dusky dolphins. No relationship was found between these longer-term grouping patterns and genetic relatedness. The d-loop
region of the mitochondrial DNA (mtDNA) was sequenced for 197 dusky dolphins. The
pattern of grouping among dolphins with different haplotypes indicates that dusky
dolphin groups are not strongly structured by maternal lineages. However, data from
eight individual dusky dolphins hint that nursery groups in Kaikoura tend to consist of
dolphins that share a maternal ancestor. This investigation raises many questions about
the nature of dusky dolphin social organization and suggests promising avenues for
finer-grained investigations into the causes and consequences of dusky dolphin group
structure.
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Birgersson, Sabina. "Personality assessment and interactions in eight captive bottlenose dolphins (Tursiops truncatus)." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-70136.
Full textAbstract:
In recent years there has been an increased interest in measuring animal personality. It is argued that personality in animals is expressed through the behaviours they display. In this study personality has been investigated in a group of eight captive bottlenose dolphins (Tursiops truncatus). Data from focal samplings were analysed by using behavioural codings and the Five-factor model consisting of Openness to experience, Conscientiousness, Extraversion, Agreeableness and Neuroticism. The results revealed that the dolphins display both distinct personality differences as well as similarities in these factors. By calculating coefficients of association it was found that the dolphins also prefer the company of certain individuals over others. Knowledge of individual personality differences and its implications can be helpful in aspects such as management and reintroduction programs, evolution and genetics and in providing a complementary perspective to explain other behavioural and cognitive studies.
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Miller, Ali P. "A Descriptive Epidemiological Study of Stranded Dolphins Along the Florida Coastline." NSUWorks, 2003. http://nsuworks.nova.edu/occ_stuetd/290.
Full textAbstract:
A collaborative project examined the disease status of dolphins that stranded along the coastline of Florida from 1996 to 2002. This study reviewed 68 freshly dead stranded dolphins (57 Tursiops truncatus and 11 others from four species). Analysis of stranding demographics and histopathologic data from the Southeastern United States Stranding Network provided important information on the prevalence of lesions in relation to sex, geographic location, season, and length in T. truncatus. The histopathologic results obtained from the other species were from an extremely small sample size and thus only provided limited insight into the diseases impacting them. Cardiomyocyte degeneration and lymphoid depletion were found in all five species examined. Some of the pathologic findings found in >20% of the T. truncatus tissues examined included pneumonitis, pulmonary fibrosis, edema, angiomatosis, nematodiasis, hepatic fibrosis, hepatocellular atrophy, glomerulonephritis, cardiomyocyte degeneration, cardiac fibrosis, lymphoid depletion, lymphadenitis, lipid depletion, gastritis, and enteritis. There were no trends seen in the histopathologic data related to sex, geographic area, or season. There were however differences in the prevalence of some lesions in relation to length class in the lung, spleen, kidney, and heart. There was a significant difference between length classes in the prevalence of the following lesions, angiomatosis (p=0.0062) in the lung, lymphoid depletion (0.043) in the spleen, glomerulonephritis (p=0.00009) in the kidney, and cardiomyocyte degeneration (p=0.022) and fibrosis (p=0.0021) in the heart, with a tendency towards more lesions in larger animals. The results of this investigation suggest that these lesions are more prevalent in larger, presumed to be older, stranded T. truncatus. The histopathologic results presented here provide important information on the diseases impacting T. truncatus around Florida, which can be used as a basis for future comparisons.