Site fidelity, residency, and abundance of bottlenose dolphins (Tursiopssp.) in Adelaide's coastal waters, South Australia

2016 ◽  
Vol 32 (4) ◽  
pp. 1381-1401 ◽  
Author(s):  
Nikki Zanardo ◽  
Guido J. Parra ◽  
Luciana M. Möller
Keyword(s):  
Coastal Waters ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
South Australia

Seasonal Abundance and Site Fidelity of Bottlenose Dolphins (Tursiops truncatus) in Mississippi Sound

2004 ◽  
Vol 30 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Carrie W. Hubard ◽  
Kathy Maze-Foley ◽  
Keith D. Mullin ◽  
William W. Schroeder
Keyword(s):  
Tursiops Truncatus ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
Seasonal Abundance ◽  
Mississippi Sound

scholarly journals Capitoline Dolphins: Residency Patterns and Abundance Estimate of Tursiops truncatus at the Tiber River Estuary (Mediterranean Sea)

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 275
Author(s):  
Daniela Silvia Pace ◽  
Chiara Di Marco ◽  
Giancarlo Giacomini ◽  
Sara Ferri ◽  
Margherita Silvestri ◽  
...  
Keyword(s):  
Population Size ◽  
Tursiops Truncatus ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
River Estuary ◽  
Suitable Habitat ◽  
Tyrrhenian Sea ◽  
Abundance Estimate ◽  
Photo Identification ◽  
Tiber River

Periodic assessments of population status and trends to detect natural influences and human effects on coastal dolphin are often limited by lack of baseline information. Here, we investigated for the first time the site-fidelity patterns and estimated the population size of bottlenose dolphins (Tursiops truncatus) at the Tiber River estuary (central Mediterranean, Tyrrhenian Sea, Rome, Italy) between 2017 and 2020. We used photo-identification data and site-fidelity metrics to study the tendency of dolphins to remain in, or return to, the study area, and capture–recapture models to estimate the population abundance. In all, 347 unique individuals were identified. The hierarchical cluster analysis highlighted 3 clusters, labeled resident (individuals encountered at least five times, in three different months, over three distinct years; n = 42), part-time (individuals encountered at least on two occasions in a month, in at least two different years; n = 73), and transient (individuals encountered on more than one occasion, in more than 1 month, none of them in more than 1 year; n = 232), each characterized by site-fidelity metrics. Open POPAN modeling estimated a population size of 529 individuals (95% CI: 456–614), showing that the Capitoline (Roman) coastal area and nearby regions surrounding the Tiber River estuary represent an important, suitable habitat for bottlenose dolphins, despite their proximity to one of the major urban centers in the world (the city of Rome). Given the high number of individuals in the area and the presence of resident individuals with strong site fidelity, we suggest that conservation plans should not be focused only close to the Tiber River mouths but extended to cover a broader scale of area.

Ecology and comparison of coastal and offshore bottlenose dolphins (Tursiops truncatus) in California

2009 ◽  
Vol 60 (6) ◽  
pp. 584 ◽  
Author(s):  
Maddalena Bearzi ◽  
Charles A. Saylan ◽  
Alice Hwang
Keyword(s):  
Tursiops Truncatus ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
Photo Identification ◽  
Santa Monica Bay ◽  
Santa Monica ◽  
Inshore Waters

Populations of coastal and offshore bottlenose dolphins (Tursiops truncatus) are considered to differ ecologically, with implications for their protection and management. We assessed occurrence, distribution and behaviour of coastal and offshore populations of dolphins during a photo-identification study in Santa Monica Bay and nearby areas (1997–2007). Bottlenose dolphins occurred year-round and were encountered on 44.2% of all surveys (n = 425). We photo-identified 647 individuals; of these, 375 (58.0%) were coastal (<1 km from shore), 241 (37.2%) offshore (1–65 km from shore) and 31 were both (4.8%). Dolphins mostly travel (69.0%) and travel-dive (61.5%), with offshore dolphins socialising more (22.6%) than coastal. There were low re-sighting rates for both coastal and offshore dolphins. Low re-sighting rates of coastal individuals provide little evidence of year-round site fidelity, suggesting their range is greater than the study area. Several individuals were re-sighted between and over 1-year periods, often foraging. This suggests that coastal dolphins: (1) are highly mobile within inshore waters, but spend time foraging in the study area, and (2) range >1 km from shore, contrary to what has been previously reported.

scholarly journals Genetic relatedness delineates the social structure of southern Australian bottlenose dolphins

2019 ◽  
Vol 30 (4) ◽  
pp. 948-959 ◽  
Author(s):  
Fernando Diaz-Aguirre ◽  
Guido J Parra ◽  
Cecilia Passadore ◽  
Luciana Möller
Keyword(s):  
Social Structure ◽  
Genetic Relatedness ◽  
Social Systems ◽  
Bottlenose Dolphins ◽  
South Australia ◽  
Intrinsic Factors ◽  
Photo Identification ◽  
The Social ◽  
Modularity Analysis ◽  
Network Metrics

AbstractSocial relationships represent an adaptive behavioral strategy that can provide fitness benefits to individuals. Within mammalian societies, delphinids are known to form diverse grouping patterns and show a variety of social systems. However, how ecological and intrinsic factors have shaped the evolution of such diverse societies is still not well understood. In this study, we used photo-identification data and biopsy samples collected between March 2013 and October 2015 in Coffin Bay, a heterogeneous environment in South Australia, to investigate the social structure of southern Australian bottlenose dolphins (Tursiops cf. australis). Based on the data from 657 groups of dolphins, we used generalized affiliation indices, and applied social network and modularity methods to study affiliation patterns among individuals and investigate the potential presence of social communities within the population. In addition, we investigated genetic relatedness and kinship relationships within and between the communities identified. Modularity analysis revealed that the Coffin Bay population is structured into 2 similar sized, mixed-sex communities which differed in ranging patterns, affiliation levels and network metrics. Lagged association rates also indicated that nonrandom affiliations persisted over the study period. The genetic analyses suggested that there was higher relatedness, and a higher proportion of inferred full-sibs and half-sibs, within than between communities. We propose that differences in environmental conditions between the bays and kinship relationships are important factors contributing to the delineation and maintenance of this social structure.

Individual movements between local coastal populations of bottlenose dolphins (Tursiops truncatus) in the northern and eastern Black Sea

2016 ◽  
Vol 98 (2) ◽  
pp. 223-229 ◽  
Author(s):  
Elena Gladilina ◽  
Olga Shpak ◽  
Valentin Serbin ◽  
Anna Kryukova ◽  
Dmitry Glazov ◽  
...  
Keyword(s):  
Black Sea ◽  
Bottlenose Dolphin ◽  
Tursiops Truncatus ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
The Black Sea ◽  
Small Range ◽  
Short Term ◽  
High Population Growth ◽  
Physical Barriers

The Black Sea subspecies of the bottlenose dolphin (Tursiops truncatus ponticus) is threatened and has a small range. Its population structure is little known: it possibly includes a few local coastal populations. We assessed connectivity between coastal groupings in six localities along 800 km of the coastline based on records of photo-identified animals between 2004 and 2014. Abundance of these groupings, as estimated, ranged between 76 and 174 individually distinctive dolphins. In total, there were 350 identified individuals, of which 91 (26%) were resighted within the same areas. However, only three cases of individual movements between local coastal populations were recorded at the distances between 135 and 325 km. Therefore, despite the absence of physical barriers, the coastal Black Sea population is fragmented into numerous resident or locally migrating groupings with site fidelity. These local populations are loosely connected to each other with rare movements between them. This fragmentation can be a factor contributing to short-term fluctuations in abundance of Black Sea bottlenose dolphins and their decline in some localities, despite the potentially high population growth rate.

Osteological variation and taxonomic affinities of bottlenose dolphins, Tursiops spp., from South Australia

2004 ◽  
Vol 52 (1) ◽  
pp. 29 ◽  
Author(s):  
Catherine M. Kemper
Keyword(s):  
Bone Resorption ◽  
Cancellous Bone ◽  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
South Australia ◽  
Wide Band ◽  
Categorical Variables ◽  
Significant Difference ◽  
Partial Correlations ◽  
Skull Measurements

Skulls and skeletons of 84 cranially mature bottlenose dolphins collected from South Australia were studied to distinguish morphological groups. The dataset comprised 38 skull measurements, 5 tooth counts/measurements, 6 coded skull features and 2 vertebral counts. There was no significant difference between sexes. Agglomerative, heirarchical cluster analyses performed on all variables and a dataset refined by eliminating those with high partial correlations produced two clear groups of skulls but with some differences in group membership between the statistical treatments. Size was an important factor in distinguishing groups, especially when categorical variables were excluded. Groups produced by cluster analysis of all variables were aligned with Tursiops truncatus and T. aduncus. In general, Tursiops truncatus was distinguished by a wide band (3-9 mm) of cancellous bone on the premaxillae, a distinct supraoccipital crest, raised naso-frontal complex, the almost complete lack of bone resorption on the pterygoid bones, a relatively wider rostrum, generally larger skull size (condylobasal length >465 mm versus <476 mm, except two skulls of 445 and 448 mm), and more than 60 vertebrae. This species was collected from open ocean coasts and sometimes stranded in groups. Tursiops aduncus generally had a narrow or no band of cancellous bone (0-5 mm), an indistinct or no supraoccipital crest, a naso-frontal complex that was not markedly raised, moderate to extensive bone resorption on the pterygoids, relatively narrow rostrum, fewer than 63 vertebrae and was collected mainly from the large gulfs. There was no significant difference between tooth diameter of T. aduncus and T. truncatus from South Australia.

Fine-scale population genetic structuring of bottlenose dolphins in Irish coastal waters

2011 ◽  
Vol 14 (4) ◽  
pp. 342-353 ◽  
Author(s):  
L. Mirimin ◽  
R. Miller ◽  
E. Dillane ◽  
S. D. Berrow ◽  
S. Ingram ◽  
...  
Keyword(s):  
Coastal Waters ◽  
Population Genetic ◽  
Bottlenose Dolphins ◽  
Fine Scale ◽  
Genetic Structuring ◽  
Scale Population

Inshore and offshore bottlenose dolphin (Tursiops truncatus) communities distinguished by association patterns near Grand Bahama Island, Bahamas

1999 ◽  
Vol 77 (4) ◽  
pp. 581-592 ◽  
Author(s):  
Kelly A Rossbach ◽  
Denise L Herzing
Keyword(s):  
Bottlenose Dolphin ◽  
Tursiops Truncatus ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
Social Groups ◽  
Foraging Strategies ◽  
Association Patterns ◽  
Simple Ratio ◽  
Water Depths

Little is known about the behavior of offshore dolphin populations. Our purpose was to distinguish and describe stable social groups of bottlenose dolphins (Tursiops truncatus) between inshore and offshore West End, Grand Bahama Island (26°42'N, 79°00'W). Photoidentification was conducted from May to September, 1994 to 1996. A simple ratio index described association patterns between dolphins. Multidimensional scaling of association indices (n = 1711 dolphin pairs) distinguished two dolphin communities consisting of 28 dolphins (19 of known sex) found inshore and 15 dolphins (12 of known sex) found greater than or equal to 27 km offshore. Eight of the 15 offshore dolphins were opportunistically photographed in the same region between 1986 and 1990. The two communities were found at different water depths (Mann-Whitney U test, p < 0.01), over distinct bottom types (Kruskal-Wallis test, p < 0.01), and used different bottom-foraging strategies. Long-term site fidelity of up to 10 years and repeated dolphin associations of up to 8 years occurred greater than or equal to 27 km from shore. Dolphins sighted greater than or equal to 15 times averaged 48 associates (SD = 11, n = 28). A dolphin's closest associate was of the same gender 74% of the time. This study is the first to report long-term site fidelity and association patterns of bottlenose dolphins found far from shore.

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