Dissertations / Theses on the topic 'Bottlenosed dolphins'
To see the other types of publications on this topic, follow the link: Bottlenosed dolphins.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Bottlenosed dolphins.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
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.
2
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.
Full text
3
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.
Full text
4
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.
Full textAbstract:
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.
5
Sloan, Peggy E. "Residency patterns, seasonality and habitat use among bottlenose dolphins, Tursiops truncatus, in the Cape Romain National Wildlife Refuge, SC /." Electronic version (PDF), 2006. http://dl.uncw.edu/etd/2006/sloanp/peggysloan.pdf.
Full text
6
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.
Full text
7
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.
Full text
8
Fougères, Erin M. "Thermoregulation in bottlenose dolphins (Tursiops truncatus)." View electronic thesis, 2008. http://dl.uncw.edu/etd/2008-1/r3/fougerese/erinfougeres.pdf.
Full text
9
Krützen, Michael Christian. "Molecular relatedness, paternity and male alliances in bottlenose dolphins (Tursiops sp.) in Shark Bay, Western Australia /." Connect to this title online, 2002. http://www.library.unsw.edu.au/~thesis/adt-NUN/public/adt-NUN20030128.113021/index.html.
Full text
10
Reddy, Kasturi. "The reproduction biology of four species of South African dolphins." Thesis, Rhodes University, 1996. http://hdl.handle.net/10962/d1005441.
Full textAbstract:
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.
11
Balmer, Brian C. "Seasonal abundance, site-fidelity, and utilization areas of bottlenose dolphins in St. Joseph Bay, Florida /." Electronic version (PDF), 2007. http://dl.uncw.edu/etd/2007-1/balmerb/brianbalmer.pdf.
Full text
12
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.
Full textAbstract:
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.
13
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.
Full text
14
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.
Full text
15
Harper, Cally. "Morphology of the melon and its tendinous connections to the facial muscles in bottlenose dolphins (Tursiops truncatus) /." Electronic version (PDF), 2007. http://dl.uncw.edu/etd/2007-1/harperc/callyharper.pdf.
Full text
16
DeLong, Caroline M. "Object-centered representations in echolocating dolphins evidence from acoustic analyses of object echoes and a human listening study /." Thesis, University of Hawaii at Manoa, 2003. http://proquest.umi.com/pqdweb?index=0&did=765084621&SrchMode=1&sid=7&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1233101570&clientId=23440.
Full text
17
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.
Full textAbstract:
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.
18
Hoffmann-Kuhnt, Matthias. "Visual and auditory vigilance in the bottlenosed dolphin." [S.l. : s.n.], 2003. http://www.diss.fu-berlin.de/2003/268/index.html.
Full text
19
Finn, Hugh C. "Conservation biology of bottlenose dolphins (Tursiops sp.) in Perth metropolitan waters." Access via Murdoch University Digital Theses Project, 2005. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20051103.135358.
Full text
20
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.
Full textAbstract:
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.
21
Silva, Monica Almeida. "Population biology of bottlenose dolphins in the Azores archipelago." Thesis, University of St Andrews, 2007. http://hdl.handle.net/10023/215.
Full textAbstract:
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.
22
Barbieri, Michelle Marie. "Physiological and behavioral thermoregulation in bottlenose dolphins (Tursiops truncatus) in Sarasota, Florida /." Electronic version (PDF), 2005. http://dl.uncw.edu/etd/2005/barbierim/michellebarbieri.pdf.
Full text
23
Brieze, Ilze. "Behavioural ecology of bottlenose dolphins (Tursiops sp.) and interactions with humans in Southeast Queensland, Australia /." [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17014.pdf.
Full text
24
Wang, John Yu-Chao. "The classification of sympatric forms of bottlenose dolphins (genus Tursiops) in Chinese waters." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0020/NQ51021.pdf.
Full text
25
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/.
Full textAbstract:
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.
26
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.
Full textAbstract:
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.
27
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.
Full textAbstract:
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
28
Dunkin, Robin C. "Ontogenetic changes in the thermal and buoyant properties of Atlantic Bottlenose Dolphin (Tursiops truncatus) blubber /." Electronic version (PDF), 2004. http://dl.uncw.edu/etd/2004/dunkinr/robindunkin.pdf.
Full text
29
Hill, Mandy Lee. "Signature whistle productions, development, and perception in free-ranging bottlenose dolphins /." Electronic version (PDF), 2002. http://dl.uncw.edu/etd/2002/hillm/mandyhill.html.
Full text
30
Boisseau, Oliver, and n/a. "The acoustic behaviour of resident bottlenose dolphins in Fiordland, New Zealand." University of Otago. Department of Marine Science, 2005. http://adt.otago.ac.nz./public/adt-NZDU20060728.140213.
Full textAbstract:
The bottlenose dolphin Tursiops truncatus is an extremely well-studied species. We have an extensive knowledge of certain aspects of their vocal behaviour, particularly from captive contexts. Bottlenose dolphins produce a rich tapestry of vocalisations, however, which have historically received minimal attention. Resident groups of bottlenose dolphins frequent the waterways of Fiordland in southwest New Zealand. These deep, sheltered fiords are ideally suited for acoustic studies.
This thesis presents the first detailed study of bottlenose dolphin acoustics in New Zealand. Both narrowband and broadband systems were used to record the vocalisations of two resident groups. Effort was distributed evenly over three years for both Doubtful Sound and Milford Sound. From 875 recordings, I proposed a repertoire of 15 discrete calls. These categories were subsequently compared using parameters measured from almost 2000 individual vocalisations. Various multivariate techniques revealed some redundancy in the proposed repertoire, and it was subsequently reduced to 12 calls.
The 12 call repertoire was compared between the potentially interbreeding populations of Doubtful Sound and Milford Sound. Fiord-specificity was revealed for many of the calls, particularly the sequenced calls and whistles. These differences suggest bottlenose dolphins use dialects, in keeping with studies of killer whales and sperm whales. As Fiordland dolphins are out of sight for 90% of the time, acoustic techniques allow inference in to subsurface behaviour. I investigated sequential relationships among sounds and between sounds and behaviours. Many calls were strongly implicated in social interactions. The vocalisations ratchet, orca and the sequenced calls were associated with periods of conflict. A number of the click-based calls were linked to diving and presumed foraging events.
Inference on the functional significance of sounds allowed an interpretation of habitat use. This appears to be the first study relating the entire vocal repertoire of a cetacean population to a complete home range. Areas important for socialising, foraging and resting are proposed. Local management decisions may be well served by this information. This study uses benign techniques to build on previous research in Fiordland, and adds a new dimension to the study of these populations.
31
com, hugh finn@bigpond, and Hugh Colin Finn. "Conservation Biology of Bottlenose Dolphins(Tursiops Sp.) in Perth Metropolitan Waters." Murdoch University, 2005. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20051103.135358.
Full textAbstract:
This thesis examines two potential conservation problems for a residential sub-population of ~75 bottlenose dolphins (Tursiops sp.) in Cockburn Sound, a small embayment within the southern metropolitan waters of Perth, Western Australia: (1) human-induced habitat change and (2) illegal feeding (i.e. unregulated provisioning) of dolphins. The work is important because Cockburn Sound is the most intensively utilised marine environment in Western Australia and industrial, commercial, and recreational uses of the area will intensify in coming decades. These considerations, coupled with the demographic and ecological vulnerability of residential
populations of small cetaceans, suggested a risk of population decline without a more informed scientific basis for management. This study (2000 2003) complemented an earlier study of the Cockburn Sound dolphins (1993 1997) to provide a decade-long longitudinal study of the population. The original contributions of this study relate to: (a) the foraging ecology of dolphins;(b) the effects and mechanisms of human-dolphin interaction, particularly interactions based on unregulated provisioning; and (c) an integration of previous research and other information.
Studies of the foraging ecology of dolphins within Cockburn Sound were undertaken between 2000-2 to determine the areas used by dolphins and their feeding behaviours so that the implications of human-induced habitat change could be assessed. These studies used belt transect
sampling and event-specific sampling of foraging aggregations of dolphins to quantify the foraging habitat use of dolphins within the Sound and to characterise spatial and temporal patterns in aggregations of foraging dolphins. The results showed that the density of foraging
dolphins varied significantly across habitats and that foraging aggregations consistently occur in an area known as the Kwinana Shelf during the austral autumn-spring period. The studies also suggested that the foraging ecology of dolphins in Cockburn Sound reflects the consistent utilisation of both: (a) low-density prey species (i.e. individual or weakly-schooling prey) and (b)
high-density prey species (i.e. schooling species such as forage fish). These findings indicate that
ecosystem-based conservations of the population should consider the conservation requirements of dolphin prey species and the ecological integrity of key foraging habitats like the Kwinana Shelf.
Human-dolphin interactions based on the illegal feeding of dolphins in Cockburn Sound escalated between 1993 and 2003. By 2003, a total of 14 individuals exhibited behaviours indicative of conditioning to human interaction by food reinforcement, including some individuals that
engaged in provisioning interactions on a chronic (i.e. long-term) basis. Observations of the effects of unregulated provisioning indicated that: (a) provisioned dolphins sustained increased higher rates of human-induced injury than non-provisioned dolphins and (b) provisioning was associated with substantial and enduring behavioural changes including changes in ranging and association patterns. Other observations of human-induced injury in Cockburn Sound included seven instances of calf entanglement. These findings indicate that the effects of illegal feeding and other forms of direct human-dolphin interaction (e.g. entanglement) could achieve biological
significance for the population.
The possible contribution of (a) human influences, (b) social learning, and (c) behavioural
propensities (e.g. age and sex) on the acquisition of an attraction response to human provisioning was examined through logistic regression analysis using age, sex, use of high-boat density areas, and the number of close associates that were previously provisioned as predictor variables and the acquisition of an attraction response as the dependent variable. This analysis was supplemented
by behavioural observations of interactions between provisioned and naïve individuals during provisioning interactions. The results supported three findings: (1) a relatively high level of exposure to human provisioners was a significant predictor for the acquisition of an attraction response by dolphins; (2) social learning contributed to the acquisition of an attraction response in
those individuals that more frequently utilised high-boat density areas; and (3) the potential contribution of behavioural propensities relating to age and sex was uncertain. These conclusions suggest that the acquisition of an attraction response to human provisioning can best be
understood as the outcome of a complex of interacting factors.
The findings also indicate: (a) the management value of individual-specific and longitudinal data for the management of harmful human-wildlife interactions and (b) the potential for social learning to contribute to the development and persistence of these interactions.
The findings of this study indicate that population decline in Cockburn Sound could be induced by: (1) a reduction in the Sounds environmental carrying capacity or (2) mortality, injury, and behavioural changes resulting from interactions with humans. The potential for such a decline and evidence demonstrating the harmful effects of human activities on dolphins supports the
application of preventative approach to the management of illegal feeding and entanglement and a precautionary approach to environmental impact assessments of proposed developments. Mitigation of direct human-dolphins like illegal feeding requires an enforcement and education program to encourage more responsible human attitudes towards interactions with dolphins.
Research on the ecology and composition of finfish assemblages and the trophic structure of the Kwinana shelf would assist efforts to mitigate the impact of human-induced habitat change.
32
Toland, Ronald W. "High frequency components in bottlenose dolphin echolocation signals /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA354939.
Full textAbstract:
Thesis (M.S. in Engineering Acoustics) Naval Postgraduate School, September 1998."september 1998." Thesis advisor(s): Thomas G. Muir, Steven R. Baker. Includes bibliographical references (p. 58). Also available online.
33
Toland, Ronald W. Jr. "High frequency components in bottlenose dolphin echolocation signals." Thesis, Monterey, California. Naval Postgraduate School, 1998. http://hdl.handle.net/10945/8469.
Full textAbstract:
Approved for public release; distribution is unlimitedThe research described in this thesis is a continuation of work started by the Applied Research Laboratories of the University of Texas at Austin into the analysis of biosonar signals. Experiments conducted in 1997 on two species of small toothed whales found these species to emit significant high frequency signal components, extending to as high as 400 to 500 kHz. To assess the importance of these high frequencies in dolphin echolocation and target identification, experiments were performed in which an acoustic filter, used to suppress the high frequencies, was placed between a dolphin and a target. Insertion Loss and Reflection Loss measurements performed on 1/4" thick and 1/2" thick Sound Absorbing Filters (SOAB) demonstrated their effectiveness at absorbing high frequencies above 150 kHz, with little reflectivity. The results from one echolocation experiment, with one dolphin, showed the animal's ability to classify targets was essentially unaffected by the insertion of the filters. Analysis of the dolphin's echolocation signals showed the animal definitely compensating for the filters, by increasing its sound energy output, especially at frequencies above 100 kHz. It is anticipated that this initial experiment will lead to future research in explaining the existence of these high frequency echolocation components.
34
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.
35
Finn, Hugh. "Conservation biology of bottlenose dolphins (Tursiops sp.) in Perth metropolitan waters." Finn, Hugh (2005) Conservation biology of bottlenose dolphins (Tursiops sp.) in Perth metropolitan waters. PhD thesis, Murdoch University, 2005. http://researchrepository.murdoch.edu.au/49/.
Full textAbstract:
This thesis examines two potential conservation problems for a residential sub-population of ~75 bottlenose dolphins (Tursiops sp.) in Cockburn Sound, a small embayment within the southern metropolitan waters of Perth, Western Australia: (1) human-induced habitat change and (2) illegal feeding (i.e. unregulated provisioning) of dolphins. The work is important because Cockburn Sound is the most intensively utilised marine environment in Western Australia and industrial, commercial, and recreational uses of the area will intensify in coming decades. These considerations, coupled with the demographic and ecological vulnerability of residential populations of small cetaceans, suggested a risk of population decline without a more informed scientific basis for management. This study (2000 - 2003) complemented an earlier study of the Cockburn Sound dolphins (1993 - 1997) to provide a decade-long longitudinal study of the population. The original contributions of this study relate to: (a) the foraging ecology of dolphins;(b) the effects and mechanisms of human-dolphin interaction, particularly interactions based on unregulated provisioning; and (c) an integration of previous research and other information.
Studies of the foraging ecology of dolphins within Cockburn Sound were undertaken between 2000-2 to determine the areas used by dolphins and their feeding behaviours so that the implications of human-induced habitat change could be assessed. These studies used belt transect sampling and event-specific sampling of foraging aggregations of dolphins to quantify the foraging habitat use of dolphins within the Sound and to characterise spatial and temporal patterns in aggregations of foraging dolphins. The results showed that the density of foraging dolphins varied significantly across habitats and that foraging aggregations consistently occur in an area known as the Kwinana Shelf during the austral autumn-spring period. The studies also suggested that the foraging ecology of dolphins in Cockburn Sound reflects the consistent utilisation of both: (a) low-density prey species (i.e. individual or weakly-schooling prey) and (b) high-density prey species (i.e. schooling species such as forage fish). These findings indicate that ecosystem-based conservations of the population should consider the conservation requirements of dolphin prey species and the ecological integrity of key foraging habitats like the Kwinana Shelf.
Human-dolphin interactions based on the illegal feeding of dolphins in Cockburn Sound escalated between 1993 and 2003. By 2003, a total of 14 individuals exhibited behaviours indicative of conditioning to human interaction by food reinforcement, including some individuals that engaged in provisioning interactions on a chronic (i.e. long-term) basis. Observations of the effects of unregulated provisioning indicated that: (a) provisioned dolphins sustained increased higher rates of human-induced injury than non-provisioned dolphins and (b) provisioning was associated with substantial and enduring behavioural changes including changes in ranging and association patterns. Other observations of human-induced injury in Cockburn Sound included seven instances of calf entanglement. These findings indicate that the effects of illegal feeding and other forms of direct human-dolphin interaction (e.g. entanglement) could achieve biological significance for the population.
The possible contribution of (a) human influences, (b) social learning, and (c) behavioural propensities (e.g. age and sex) on the acquisition of an attraction response to human provisioning was examined through logistic regression analysis using age, sex, use of high-boat density areas, and the number of close associates that were previously provisioned as predictor variables and the acquisition of an attraction response as the dependent variable. This analysis was supplemented by behavioural observations of interactions between provisioned and naive individuals during provisioning interactions. The results supported three findings: (1) a relatively high level of exposure to human provisioners was a significant predictor for the acquisition of an attraction response by dolphins; (2) social learning contributed to the acquisition of an attraction response in those individuals that more frequently utilised high-boat density areas; and (3) the potential contribution of behavioural propensities relating to age and sex was uncertain. These conclusions suggest that the acquisition of an attraction response to human provisioning can best be understood as the outcome of a complex of interacting factors.
The findings also indicate: (a) the management value of individual-specific and longitudinal data for the management of harmful human-wildlife interactions and (b) the potential for social learning to contribute to the development and persistence of these interactions. The findings of this study indicate that population decline in Cockburn Sound could be induced by: (1) a reduction in the Sound?s environmental carrying capacity or (2) mortality, injury, and behavioural changes resulting from interactions with humans. The potential for such a decline and evidence demonstrating the harmful effects of human activities on dolphins supports the application of preventative approach to the management of illegal feeding and entanglement and a precautionary approach to environmental impact assessments of proposed developments. Mitigation of direct human-dolphins like illegal feeding requires an enforcement and education program to encourage more responsible human attitudes towards interactions with dolphins. Research on the ecology and composition of finfish assemblages and the trophic structure of the Kwinana shelf would assist efforts to mitigate the impact of human-induced habitat change.
36
Rogowski, Justin. "Investigation into automatic identification of bottlenose dolphins using data fusion techniques." Thesis, University of Derby, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506682.
Full text
37
Natoli, Ada. "Molecular ecology of bottlenose (Tursiops sp.) and common (Delphinus sp.) dolphins." Thesis, Durham University, 2004. http://etheses.dur.ac.uk/2983/.
Full textAbstract:
Bottlenose (Tursiops sp.) and common dolphins (Delphinus sp.) are amongst the most common small cetaceans. They both have a world-wide distribution from warm temperate to tropical waters inhabiting pelagic and coastal waters, and they both show high morphological variability throughout their range, leaving the taxonomic issues in both species unresolved. This thesis provides a comparative assessment of these two species, by molecular analysis, especially in the context of comparing coastal and pelagic populations of each species. The aim is to better understand the evolutionary processes and the factors involved in shaping the population structure in small delphinids. The strategy 1 followed was: 1) Analyse the population structure of the bottlenose and common dolphins on a worldwide scale and compare large scale patterns in the context of known similarities and differences with respect to life history. 2) Analyse populations on a smaller geographic scale (Mediterranean Sea and South Africa) to further understand the relationship between habitat and population generic structure. On a worldwide scale, bottlenose dolphins showed high genetic diversity and strong population structure, both between different and similar morphotypes, suggesting limited gene flow. Two populations, of the same morphotype, have diverged considerably to the extent that they should be considered different species. Common dolphins showed lower genetic diversity and weak population structure even over a large geographic range, suggesting higher level of gene flow. However, this species also has similar morphotypes that were genetically differentiated from one another. On a smaller geographic scale, we found a similar pattern of population structure, with the bottlenose dolphin showing higher population divergence than common dolphins. However, both species provided evidence supporting the role of habitat in defining population structure in these species. These findings should facilitate the development of effective conservation and management strategies for these species, especially for the specific case studies for populations in the Mediterranean Sea and off the Natal coast of South Africa.
38
Clegg, Isabella louisa. "Developing welfare parameters for bottlenose dolphins (Tursiops truncatus) under human care." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCD055/document.
Full textAbstract:
La science du bien-être animal est une discipline bien établie qui permet de faire des mesures objectives. Les grands dauphins (Tursiops truncatus) sont une espèce de cétacés communément présente en captivité, et bien que des questions se posent sur la qualité de leur vie dans cet environnement, très peu d'études ont porté sur la mesure objective de leur bien-être. Cette thèse répond à ce manque de données en développant des indicateurs de bien-être basé sur l’animal, ici le grand dauphin. Une revue bibliographique initiale a identifié des mesures potentielles de bien-être, avant que des indicateurs comportementaux choisis aient été mesurés par rapport aux sessions d’entrainement. Un test de biais de jugement a alors été adapté aux dauphins, où des biais optimistes ont été significativement liés aux fréquences les plus hautes de nage synchronisée durant leur 'temps libre' et aux fréquences les plus basses de comportement anticipatoire avant les sessions d’entrainement. Une avant dernière étude a montré que le comportement anticipatoire prédisait la participation à l'événement à venir, et que des Interactions Humaines-Animales positives étaient anticipées plus que l’introduction de jouets. Une dernière expérience en cours a développé un protocole standardisé pour mesurer la motivation des dauphins pendant des sessions d’entrainement par rapport aux problèmes de bien-être sociaux et de santé. Bien que le bien-être global soit toujours difficile à mesurer, cette thèse propose des premières mesures d'émotions et d’états affectifs chez le dauphin. La nage synchronisée est un indicateur probable d'émotions positives, bien que plus de recherches doivent examiner la variabilité entre divers contextes. Le comportement anticipatoire semble témoigner de la motivation pour des événements à venir et nous suggérons qu'il reflète une sensibilité à la récompense comme chez d'autres animaux : des travaux ultérieurs portant sur des seuils de fréquence le transformerait en indicateur de bien-être pertinent. Un objectif majeur de la thèse est de stimuler plus de recherches sur des mesures de bien-être chez des grands dauphins et d'autres espèces de cétacés en captivitéWelfare science is now an established discipline which enables objective measurements of animal welfare to be made. Bottlenose dolphins (Tursiops truncatus) are a common cetacean species kept in captivity, and although questions are arising over their quality of life in this environment, very few studies have focussed on objectively measuring their welfare. This thesis aimed to address this lack of data by developing animal-based indicators of bottlenose dolphin welfare. An initial review identified potential dolphin welfare measures, before selected behavioural indicators were measured in relation to training sessions. A judgement bias test was then adapted to dolphins, where optimistic biases were significantly linked to higher frequencies of synchronous swimming in their ‘free-time’ and lower frequencies of anticipatory behaviour before training sessions, (concurring with there ward-sensitivity theory). A penultimate study showed that anticipatory behaviour predicted participation in the upcoming event, and positive Human-Animal Interactions were anticipated more than access to toys. A final, on-going experiment has developed and applied a standardised protocol for measuring dolphins’motivation during training sessions in relation to social and health-related welfare problems. Although overall welfare is still difficult to measure, this thesis has proposed some first measures of dolphin emotions and affective states. Synchronous swimming is a likely indicator of positive emotions and social support, although more research should investigate variability between contexts. Anticipatory behaviour seemed to indicate motivation for events, and we suggest it reflects reward sensitivity as in other animals : further work into frequency thresholds would render it a valuable welfare indicator. A major objective of the thesis is to stimulate more research on welfare measures for bottlenose dolphins and other cetacean species in captivity
39
Hudak, Christine A. "Habitat Utilization by Bottlenose Dolphins (Tursiops truncatus) in Biscayne Bay, Florida." NSUWorks, 2003. http://nsuworks.nova.edu/occ_stuetd/116.
Full textAbstract:
Bottlenose dolphins (Tursiops truncatus) exhibit variable distribution patterns, depending upon their geographic location. Habitat utilization patterns in Biscayne Bay, Florida, were examined using the Biscayne Bay Bottlenose Dolphin Photo-ID database obtained from the National Oceanic and Atmospheric Administration (NOAA) Southeast Fisheries Science Center (SEFSC) Miami Laboratory. Habitat coverages in Biscayne Bay were obtained from the Atlas of Marine Resources Version 1.3B CD and the Biscayne Bay National Park CD. Dolphin sightings were overlaid on the habitat coverages using GIS Arcview software.
The effects of habitat, season, behavior, zone (sectioned area of Biscayne Bay), and depth on patterns of bottlenose dolphin distribution were examined by analysis of variance to determine the significance of the factors. The total number of dolphins observed during the sightings analyzed was 1,538. The number of dolphins per sighting varied from 1 to 28 dolphins, with a mean of 5.14. The average number of dolphins per survey effort was 10.32. Several significant changes in habitat have occurred between 1991-1992 to 1997. The changes in habitat had some influence on the dolphins’ behavior distribution. The highest proportion of all behavior types was found in moderately dense seagrass beds and dredge bottom areas. Habitat quality (habitat types) of Biscayne Bay influenced dolphin sightings, while habitat quantity (habitat area) influenced dolphin numbers. Analysis of variance statistics supported the strong significant effect of habitat on the variation of sightings and dolphin numbers (P < 0.001).
No significant difference in sightings was found between seasons or zones throughout the study period. The fall season had the lowest number of dolphins and sightings. The low number of surveys during the fall season does not account for all the influence on the dolphin numbers. Strong significant differences were observed between behaviors (P < 0.001). The majority of initial behaviors included traveling, feeding, and socializing. Changes in behaviors were apparent as observations continued. It was determined that the proximity of the research vessel and the duration of observation influenced dolphin behavior. Tail slap and chuffing behavior and boat interaction doubled and quadrupled, respectively during sightings. A strong variation in the number of sightings and number of dolphins occurred between different depths (P < 0.001). The majority of dolphins were observed in depths of 2.1 - 3 meters. This coincides with the fact that the majority of Biscayne Bay depths are within that range. A time series analysis was performed to determine if there was a cycle present in the pattern of dolphin distribution, and no significant cycle was found. Future analysis of dolphin composition (resident, migratory, nomadic) may yield cyclic patterns.
40
Cole, Katharine Ruth. "Energetics in the Atlantic bottlenose dolphin, Tursiops truncatus Montagu." Thesis, University of Aberdeen, 1995. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU543518.
Full textAbstract:
Various aspects of energetics of the Atlantic bottlenose dolphin, Tursiops truncatus Montagu, were investigated, including the relationship between ventilation rate and behaviour, the structure of the breath, basal metabolic rate, and the cost of echolocation. An ethogram was defined through observation of a sub-group of seven dolphins, which proved to be representative for dolphins in captivity. Ventilation rates for the behaviours within the ethogram were measured using a stopwatch, and analysis of spoken and filmed commentaries, on the behaviour of 36 dolphins at five study sites. Ventilation rate was found to vary significantly with behaviour, and was used to estimate the relative costs for different behaviours. All the behaviours were assumed to be aerobic as there was no correlation between consecutive apnoeic periods, and there were no "carry-over" effects when dolphins changed behaviour. Swimming at approximately 1.5 m s-1 and 2 m -1s, incurred similar ventilation rates, and presumably costs, to stationary resting. Ventilation rate increased as speed increased, or when the dolphins swam at the surface. Dolphins spent the majority of time for which they were observed in the behaviours which incurred the lowest ventilation rates. Six ventilatory parameters were measured in 29 dolphins. These included expiration and inspiration duration, the time for which the blowhole was open, and the time spent at the surface. Mean breath duration (expiration + inspiration) was 0.860.16 s (n=2762). The duration of both expiration and inspiration could be varied, although inspiration was more flexible than expiration. Expiration time could be increased by reducing inspiration time or by extending the time the blowhole was open. Inspiration time had a significant influence on the time the blowhole was open and the time spent at the surface.
41
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.
42
Stuby, Richard George. "A stochastic measure of similarity between dolphin signature whistles /." This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-03042009-040851/.
Full text
43
Blackwood, Diane Joyner. "Vocal response times to acoustic stimuli in white whales and bottlenose dolphins." Diss., Texas A&M University, 2003. http://hdl.handle.net/1969.1/511.
Full textAbstract:
Response times have been used to explore cognitive and perceptual processes since 1850 (Donders, 1868). The technique has primarily been applied to humans, birds, and terrestrial mammals. Results from two studies are presented here that examine response times in bottlenose dolphins (Tursiops truncatus) and white whales (Delphinapterus leucas). One study concerned response times to stimuli well above the threshold of perceptibility of a stimulus, and the other concerned response times to stimuli near threshold. Two white whales (Delphinapterus leucas) and five Atlantic bottlenose dolphins (Tursiops truncatus) were presented stimuli well above threshold. The stimuli varied in type (tone versus pulse), amplitude, duration, and frequency. The average response time for bottlenose dolphins was 231.9 ms. The average response time for white whales was 584.1 ms. There was considerable variation between subjects within a species, but the difference between species was also found to be significant. In general, response times decreased with increasing stimulus amplitude. The effect of duration and frequency on response time was unclear. Two white whales (Delphinapterus leucas) and four Atlantic bottlenose dolphins (Tursiops truncatus) were given audiometric tests to determine masked hearing thresholds in open waters of San Diego Bay (Ridgway et al., 1997). Animals were tested at six frequencies over a range from 400 Hz to 30 kHz using pure tones. Hearing thresholds varied from 87.5 dB to 125.5 dB depending on the frequency, masking noise intensity and individual animal. At threshold, median response time across frequencies within each animal varied by about 150 ms. The two white whales responded significantly slower (∼670 msec, p<0.0001) than the four dolphins (∼410 msec). As in terrestrial animals, reaction time became shorter as stimulus amplitude increased (Wells, 1913; Stebbins, 1966). Across the two studies, the dolphins as a group were faster in the abovethreshold study than in the nearthreshold study. White whales had longer response times than bottlenose dolphins in both studies. Analysis of response time with an allometric relation based on weight shows that the difference in weight can explain a significant part of the difference in response time.
44
Nowacek, Douglas Paul. "Sound use, sequential behavior and ecology of foraging bottlenose dolphins, Tursiops truncatus." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85611.
Full textAbstract:
Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 1999.Includes bibliographical references.
Odontocetes are assumed to use echolocation for navigation and foraging, but neither of these uses of biosonar has been conclusively demonstrated in free-ranging animals. Many bats are known to use echolocation throughout foraging sequences, changing the structure and timing of clicks as they progress towards prey capture. For odontocetes, however, we do not know enough about their foraging behavior to describe such sequences. To conduct detailed behavioral observations of any subject animal, the observer must be able to maintain continuous visual contact with the subject for a period commensurate with the duration of the behavior(s) of interest. Behavioral studies of cetaceans, which spend approximately 95% of their time below the water's surface, have been limited to sampling surface behavior except in special circumstances, e.g. clear-water environments, or with the use of technological tools. I addressed this limitation through development of an observation platform consisting of a remote controlled video camera suspended from a tethered airship with boat-based monitoring, adjustment, and recording of video. The system was used successfully to conduct continuous behavioral observations of bottlenose dolphins in the Sarasota Bay, FL area. This system allowed me to describe previously unreported foraging behaviors and elucidate functions for behaviors already defined but poorly understood. Dolphin foraging was modeled as a stage-structured sequence of behaviors, with the goal-directed feeding event occurring at the end of a series of search, encounter, and pursuit behaviors. The behaviors preceding a feeding event do not occur in a deterministic sequence, but are adaptive and plastic. A single-step transition analysis beginning with prey capture and receding in time has identified significant links between observed behaviors and demonstrated the stage-structured nature of dolphin foraging. Factors affecting the occurrence of specific behaviors and behavioral transitions include mesoscale habitat variation and individual preferences. The role of sound in foraging, especially echolocation, is less well understood than the behavioral component. Recent studies have explored the use of echolocation in captive odontocete foraging and presumed feeding in wild animals, but simultaneous, detailed behavioral and acoustic observations have eluded researchers. The current study used two methods to obtain acoustic data. The overhead video system includes two towed hydrophones used to record 'ambient' sounds of dolphin foraging. The recordings are of the 'ambient' sounds because the source of the sounds, i.e. animal, could not be localized. Many focal follows, however, were conducted with single animals, and from these records the timing of echolocation and other sounds relative to the foraging sequence could be examined. The 'ambient' recordings revealed that single animals are much more vocal than animals in groups, both overall and during foraging. When not foraging, single animals vocalized at a rate similar to the per animal rate in groups of>=2 animals. For single foraging animals, the use of different sound types varies significantly by the habitat in which the animal is foraging. These patterns of use coupled with the characteristics of the different sound types suggest specific functions for each. The presence of multiple animals in a foraging group apparently reduces the need to vocalize, and potential reasons for this pattern are discussed. In addition, the increased vocal activity of single foraging animals lends support to specific hypotheses of sound use in bottlenose dolphins and odontocetes in general. The second acoustic data collection method records sounds known to be from a specific animal. An acoustic recording tag was developed that records all sounds produced by an animal including every echolocation click. The tag also includes an acoustic sampling interval controller and a sensor suite that measures pitch, roll, heading, and surfacing events. While no foraging events occurred while an animal was wearing an acoustic data logger, the rates of echolocation and whistling during different activities, e.g. traveling, were measured.
by Douglas Paul Nowacek.
Ph.D.
45
Gridley, Teresa. "Geographic and species variation in bottlenose dolphin (Tursiops spp.) signature whistle types." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/1910.
Full textAbstract:
Geographic variation in the whistle vocalisations of dolphins has previously been reported. However, most studies have focused on the whole whistle repertoire, with little attempt to classify sounds into biologically relevant categories. Common bottlenose dolphins (Tursiops truncatus) use individually distinctive signature whistles which are thought to help maintain contact between conspecifics at sea. These whistles may show a different kind of variation between populations than non-signature whistles. Here I investigate signature whistle use and variation in the two recognised species of bottlenose dolphins (T. truncatus and T. aduncus) from populations inhabiting the coastal waters of the North America, Scotland, South Africa, Tanzania, Japan, Australia and New Zealand, and one captive colony. I identified likely signature whistles (signature whistles types, SWTs) from acoustic recordings by combining two novel techniques: automated contour categorisation in ARTwarp (Deecke and Janik, 2006) and a specific bout analysis based on the timing of signature whistle production in T. truncatus termed SIGID (Janik et al. in press). Three ways of categorising the contours were tested and between 87 and 111 SWTs were identified in total. Repeated emissions of stereotyped contours were apparent in the repertoire of all T. aduncus populations using both automated and human observer categorisation, providing good evidence for signature whistle use in this species. There was significant inter-specific variation in the frequency parameters, looping patterns and duration of SWTs. Inflection points, duration and measures of SWT complexity showed high variation within populations, suggesting inter- and intra-individual modification of these parameters, perhaps to enhance identity encoding or convey motivational information. Using 328 bases of the mtDNA control region, I found high levels of population differentiation (FST and φST) within the genus Tursiops. These data do not support a link between mtDNA population differentiation and variability in call type. Instead, morphological variations at the species level, and learned differences at the population level, better explain the variation found.
46
Amir, Omar A. "Biology, ecology and anthropogenic threats of Indo-Pacific bottlenose dolphins in east Africa." Doctoral thesis, Stockholm : Department of zoology, Stockholm university, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-34472.
Full textAbstract:
Diss. (sammanfattning) Stockholm : Stockholms universitet, 2010.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 4: In progress. Paper 5: Submitted.
47
Powell, Jessica R. "Depredation and angler interactions involving bottlenose dolphins (Tursiops truncatus) in Sarasota Bay, Florida." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002920.
Full text
48
Sayigh, Laela Suad. "Development and functions of signature whistles of free-ranging bottlenose dolphins, Tursiops truncatus." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12900.
Full text
49
Hastie, Gordon Drummond. "Fine-scale aspects of habitat use and behaviour by bottlenose dolphins (Tursiops truncatus)." Thesis, University of Aberdeen, 2000. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU145531.
Full textAbstract:
This study explored habitat use and behaviour in a population of bottlenose dolphins (Tursiops truncatus) within the Moray Firth, Scotland between 1997 and 1999. The spatial patterns of use and the surface and diving behaviour of dolphins were studied with respect to key habitat variables in an intensively used region within the populations range. This is a relatively small, coastal channel that is topographically variable in relation to surrounding waters. The study describes the development and application of a land-based technique to study the fine-scale spatial distribution of dolphins and showed that their distribution was significantly related to water depth and the gradient of the seabed; dolphins were sighted most frequently in the deepest regions with the steepest seabed slopes. There was a clear monthly pattern in the use of the area between May and September with sighting frequency peaking during July. The presence of dolphins was not, however, significantly related to tidal or diurnal cycles. Using passive acoustic localisation techniques, the diving behaviour of dolphins was studied and showed that, within the deepest regions of the study area, dolphins used the full water column and consistently dived to depths of around 50 metres, close to the seabed. However the majority of their time appeared to be spent within the surface layers of the water column. In addition, by localising calls that have been associated with feeding (Janik, 2000), it appeared that certain forms of feeding behaviour occurred primarily at depths of between 30 and 40 metres.
50
Arso, Civil Mònica. "Population ecology of bottlenose dolphins (Tursiops truncatus) off the east coast of Scotland." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/6543.
Full textAbstract:
The population of bottlenose dolphins off the east coast of Scotland has been studied since the late 1980s, initially focused on the inner Moray Firth, where a Special Area of Conservation (SAC) was designated under the EU Habitats Directive. The population has since expanded its distributional range and currently ranges from the Moray Firth to the Firth of Forth. The main aims of this thesis were: (1) to estimate population parameters for this population using a 25 year individual recognition dataset, and (2) to increase knowledge of the distribution and abundance of dolphins in areas outside the SAC, especially to investigate areas of high use in St Andrews Bay. Apparent survival rate for adults and sub–adult dolphins was estimated at 0.946 (SE=0.005) accounting for temporary emigration caused by the population's range expansion. Sex-specific survival was estimated for males (0.951, SE=0.013) and females (0.956, SE=0.011) using multistate models to minimize bias caused by individuals of unknown sex. Using a newly developed approach, fecundity rate was estimated at 0.222 (95% CI=0.218-0.253) from an expected mean inter-birth interval of 4.49 yrs (95% CI=3.94-4.93). Total population size was estimated as ~200 individuals, after accounting for temporary emigration and for heterogeneity in capture probabilities. In St Andrews Bay, an area used regularly in summer by approximately half the estimated population, habitat use modelling identified the entrance to the Firth of Tay and waters around Montrose as high use areas for dolphins, whose presence was influenced by tidal current speed and direction. The results suggest that the conservation and management plan for this small and isolated population of bottlenose dolphins should be reviewed to adapt it to current knowledge, especially regarding the uncertainty around the potential impacts of offshore renewable energy developments off the east coast of Scotland.