RANGE CHARACTERISTICS OF PACIFIC COAST BOTTLENOSE DOLPHINS (<i>TURSIOPS TRUNCATUS</i>) IN THE SOUTHERN CALIFORNIA BIGHT

Defran, R. H.; Weller, David W.; Kelly, Dennis L.; Espinosa, Miriam A.

doi:10.1111/j.1748-7692.1999.tb00808.x

Cited by 107 publications

(124 citation statements)

References 30 publications

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“…Researchers at two study sites have provided estimates of bottlenose dolphin ranges. On the Californian coast, individual dolphins con'lmonly range over 2':50-483 km of coastline in a 0.5-km-wide strip (Defran et al, 1999). On the Florida Gulf coast, the population is hypothesized to be structured into· geographically acljacent "communities," with some social mixing and geographic overlap (see summaries in Scott et al, 1990; Wells, 1991).…”

Section: Discussionmentioning

confidence: 99%

Summer Movement Patterns of Bottlenose Dolphins in a Texas Bay

Lynn

Würsig

2002

goms

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Section: Discussionmentioning

confidence: 99%

Summer Movement Patterns of Bottlenose Dolphins in a Texas Bay

Lynn

Würsig

2002

goms

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“…One example is the permanent expansion of the northern extent of the range of coastal bottlenose dolphins along the California coast during the 1982-83 El Niño (Defran et al, 1999). Another example is the increased abundance of humpback whales (Megaptera novaeangliae) in Monterey Bay during the 1997-98 El Niño (Benson et al, 2002).…”

Section: Patterns Of Temperature Oscillationmentioning

confidence: 99%

“…Habitat preferences likely refl ect differences in preferred prey. Dolphins may follow prey habitats as they shift not only seasonally but through large-scale climatedriven changes such as the El Niño-Southern Oscillation (ENSO) or the Pacific Decadal Oscillation (PDO) (Shane, 1995;Defran, 1999;Benson et al, 2002;Ballance et al, 2006).We examined the distribution and relative abundance of multiple species of small cetaceans across shifting temperature regimes off South- ern California by using a unique coupled cetaceanoceanographic long-term data set. This data set enables a rare opportunity to assess interdecadal changes in cetacean distribution over a broad spatial extent.…”

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confidence: 99%

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Effects of fluctuations in sea-surface temperature on the occurrence of small cetaceans off Southern California

Henderson¹,

Forney²,

Barlow³

et al. 2014

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Abstract-The link between ocean temperature and spatial and temporal distribution patterns of 8 species of small cetaceans off Southern California was examined during the period 1979-2009. Averages and anomalies of sea-surface temperatures (SSTs) were used as proxies for SST fluctuations on 3 temporal scales: seasonal, El Niño-Southern Oscillations (ENSO), and Pacific Decadal Oscillations (PDO). The hypothesis that cetacean species assemblages and habitat associations in southern California waters co-vary with these periodic changes in SST was tested by using generalized additive models. Seasonal SST averages were included as a predictor in the models for Dall's porpoise (Phocoenoides dalli), and common dolphins (Delphinus spp.), northern right whale dolphin (Lissodelphis borealis), and Risso's dolphin (Grampus griseus). The ENSO index was included as a predictor for northern right whale, long-beaked common (Delphinus capensis), and Risso's dolphins. The PDO index was selected as a predictor for Dall's porpoise and Pacific white-sided (Lagenorhynchus obliquidens), common, and bottlenose (Tursiops truncatus) dolphins. A metric of bathymetric depth was included in every model, and seafloor slope was included in 5 of the 9 models, an indication of a distinctive spatial distribution for each species that may represent niche or resource partitioning in a region where multiple species have overlapping ranges. Temporal changes in distribution are likely a response to changes in prey abundance or dispersion, and these patterns associated with SST variation may foreshadow future, more permanent shifts in distribution range that are due to global climate change.Cetaceans are higher-trophic-level marine predators whose movement patterns and habitat preferences are typically related to the distribution of their prey (Wishner et al., 1995;Gowans et al. 2007). Unlike baleen whales, small cetaceans (porpoises, dolphins, and small-toothed whales) generally do not undertake oceanscale annual migrations to track prey or to move between breeding and feeding grounds. Rather, small cetaceans may display a high degree of site fi delity, or they may move seasonally inshore and offshore or along regional-scale coastlines (Leatherwood et al., 1984;Dohl et al., 1986;Shane et al., 1986;Forney and Barlow, 1998).Although many small cetacean species may overlap in any one region of their total range, they often differ in their occurrence or habitatuse patterns, perhaps refl ecting competitive exclusion or niche partitioning. This separation of habitat and resources often occurs along depth, slope, and sea-surface temperature (SST) gradients (Reilly, 1990;Forney, 2000;Ballance et al., 2006;MacLeod et al., 2008). Habitat preferences likely refl ect differences in preferred prey. Dolphins may follow prey habitats as they shift not only seasonally but through large-scale climatedriven changes such as the El Niño-Southern Oscillation (ENSO) or the Pacific Decadal Oscillation (PDO) (Shane, 1995;Defran, 1999;Benson et al., 2002;Ballance et al., 200...

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“…We 85 Distances among adjacent locations should allow for individual exchange considering the 86 dispersal capabilities of the species, and 4) Photo-identification catalogs of coastal bottlenose 87 dolphin populations must be available. Detailed descriptions on the ecology of the study areas 88 and the biology of dolphin populations in those areas are provided elsewhere (see Espinosa, 1986, 89 Ballance, 1987Salinas and Bourillón, 1988;Acevedo, 1989; Ballance, 1990 Ballance, , 1992 Delgado, 90 1996 Delgado, 90 , 2002 Caldwell, 1992;Heckel, 1992;Schramm, 1993;Silber et al, 1994; Silber and Fertl, 91 1995; López, 1997López, , 2002Defran et al, 1999;Díaz, 2001;Orozco, 2001; Guzón, 92 2002;Morteo, 2002;Rodríguez et al, 2003;Ladrón de Guevara and Heckel, 2004; Morteo et al, 93 2004;Ramírez et al, 2005;Mellink-Bijtel and Orozco-Meyer, 2006; Pérez-Cortés, 2006; 94 Rodríguez-Vázquez, 2008;Morteo et al, 2012, 2015 Ruiz-Hernández, 2014; 95 Zepeda-Borja, In prep.). Study areas were grouped by region into 1) Pacific Ocean, 2) Gulf of 96 California and 3) Gulf of Mexico (Fig.…”

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confidence: 99%

Phenotypic variation in dorsal fin morphology of coastal bottlenose dolphins (Tursiops truncatus) off Mexico

Morteo

Rocha‐Olivares

Morteo

et al. 2017

Preprint

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Geographic variation in external morphology is thought to reflect an interplay between genotype and the environment. Morphological variation has been well-described for a number of cetacean species, including the bottlenose dolphin (Tursiops truncatus). In this study we analyzed dorsal fin morphometric variation in coastal bottlenose dolphins to search for geographic patterns at different spatial scales. A total of 533 dorsal fin images from 19 available photo-identification catalogs across the three Mexican oceanic regions (Pacific Ocean n=6, Gulf of California n=6 and, Gulf of Mexico n=7) were used in the analysis. Eleven fin shape measurements were analyzed to evaluate fin polymorphism through multivariate tests. Principal Component Analysis on log-transformed standardized ratios explained 94% of the variance. Canonical Discriminant Function Analysis on factor scores showed separation among most study areas (p<0.05) with exception of the Gulf of Mexico where a strong morphometric cline was found. Possible explanations for the observed differences are related to environmental, biological and evolutionary processes.Shape distinction between dorsal fins from the Pacific and those from the Gulf of California were consistent with previously reported differences in skull morphometrics and genetics.Although the functional advantages of dorsal fin shape remains to be assessed, it is not unlikely that over a wide range of environments, fin shape may represent a trade-off among thermoregulatory capacity, hydrodynamic performance and the swimming/hunting behavior of the species. (Aleyev, 1977; Pauly and 48 Palomares, 1989;Fish, 1998;Wright, 2000), and this is also widely accepted in 49 cetaceans (Fish and Hui, 1991; Berta and Sumich, 1999;Fish and Rohr, 1999; Reynolds et al., 50 2000;Morteo, 2003). Morphological variation of the dorsal fin, to some extent, has been used for 51 population and/or species identification (Lang and Pryor, 1966;Aleyev, 1977;Fish, 1998; 52 Weller, 1998;Morteo et al., 2005;Felix et al., 2017). 5354 The dorsal fin of delphinids is important at two functional levels: thermoregulatory and 55 hydrodynamic. Little empirical evidence exists, however, regarding the integrated performance 56 of dorsal fins for most cetacean species (Lang, 1966;Fish and Rohr, 1999; 57 Meagher et al., 2002; Pavlov Westgate et al., 2007;Barbieri et al., 2010;and Rashad, 2012; van 58 der Hoop et al., 2014). Estimating integrated performance is challenging since plasticity may be 59 in part regulated by the energetic cost of different swimming behaviors related to locating, 60 chasing, handling, and ingesting prey, thus maneuvering abilities may be important in feeding 61 success, and the dorsal fin may play an important role for swimming stabilization 62 Fish and Rohr, 1999). Also, the dorsal fin is the only appendage that is constantly exposed to 63 ambient air, and thus is subject to different thermoregulatory conditions from the rest of the body 64 Westgate et al., 2007;Barbieri et al., 2010). (Walker, 1...

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RANGE CHARACTERISTICS OF PACIFIC COAST BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) IN THE SOUTHERN CALIFORNIA BIGHT

Cited by 107 publications

References 30 publications

Summer Movement Patterns of Bottlenose Dolphins in a Texas Bay

Summer Movement Patterns of Bottlenose Dolphins in a Texas Bay

Effects of fluctuations in sea-surface temperature on the occurrence of small cetaceans off Southern California

Phenotypic variation in dorsal fin morphology of coastal bottlenose dolphins (Tursiops truncatus) off Mexico

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