Improving Management of Overlapping Bottlenose Dolphin Ecotypes Through Spatial Analysis and Genetics

Torres, Leigh G.; Rosel, Patricia E.; D’Agrosa, Caterina; Read, Andrew J.

doi:10.1111/j.1748-7692.2003.tb01317.x

Cited by 80 publications

(90 citation statements)

References 20 publications

(17 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Genetic differentiation between ecotypes has been used to characterise ecotype distribution according to water depth and/or distance to the coast. In the North-West Atlantic, the pelagic ecotype occurs mainly in waters beyond 34 km from shore and 34 m depth while the coastal one occurs at least up to 7.5 km from shore (Torres et al 2003). In the Gulf of California, a distribution break is found around the 60m-isobath (Segura et al 2006).…”

Section: Introductionmentioning

confidence: 94%

High gene flow in oceanic bottlenose dolphins (Tursiops truncatus) of the North Atlantic

et al. 2007

View full text Add to dashboard Cite

Despite the openness of the oceanic environment, limited dispersal and tight social structure often induce genetic structuring in marine organisms, even in large animals such as cetaceans. In the bottlenose dolphin, mitochondrial and nuclear DNA analyses have revealed the existence of genetic differentiation between pelagic (or offshore) and coastal (or nearshore) ecotypes in the western North Atlantic, as well as between coastal populations. Because previous studies concentrated on continental margins, we analysed the population structure of bottlenose dolphins in two of the most isolated archipelagos of the North Atlantic: the Azores and Madeira. We analysed 112 samples collected on live animals in the two archipelagos, and nine samples collected on stranded animals in Madeira and mainland Portugal. Genetic analyses consisted in molecular sexing, sequencing of part of the mitochondrial hypervariable region, and screening of ten microsatellite loci. We predicted that: 1/ there is at least one pelagic and one or more coastal populations in each archipelago; 2/ populations are differentiated between and possibly within archipelagos. Contrary to these predictions, results indicated a lack of population structure in the study area. In addition, comparison with published sequences revealed that the samples from the Azores and Madeira were not significantly differentiated from samples of the pelagic population of the western North Atlantic. Thus, bottlenose dolphins occurring in the pelagic waters of the North Atlantic belong to a large oceanic population, which should be regarded as a single conservation unit. Unlike what is known for coastal populations, oceanic bottlenose dolphins are able to maintain high levels of gene flow.

show abstract

Section: Introductionmentioning

confidence: 94%

High gene flow in oceanic bottlenose dolphins (Tursiops truncatus) of the North Atlantic

et al. 2007

View full text Add to dashboard Cite

show abstract

“…However, the mean and median lengths of adult animals in their samples were far smaller ( This difference in data can be explained if there are 2 morphs inhabiting the Black Sea, a large and a small one. Sympatric distribution of a coastal (smallsized) and an offshore (large-sized) population is usual for many delphinids (Perrin 1984): such ecotypes of common bottlenose dolphins exist in the western North Atlantic (Hersh & Duffield 1990, Torres et al 2003 and possibly in the Mediterranean (Kerem et al 2013). In fact, stable coastal groups of bottlenose dolphins inhabit the northern Black Sea (Bel'kovich 1978, Gladilina et al 2013, whereas large aggregations are also recorded in the offshore waters (Mikhalev 2005).…”

Section: Historical Variation and Population Heterogeneitymentioning

confidence: 99%

Small dolphins in a small sea: age, growth and life‑history aspects of the Black Sea common bottlenose dolphin Tursiops truncatus

Gol’din¹,

Gladilina²

2015

Aquat. Biol.

View full text Add to dashboard Cite

“…1). Torres et al (2003) classified all bottlenose dolphins seen farther than 34 km from the shore into the oceanic ecotype, and the placement here puts bottlenose dolphins well offshore of that distance (Fig. 4).…”

Section: North Of Hatterasmentioning

confidence: 99%

Community structure in pelagic marine mammals at large spatial scales

Schick¹,

Halpin²,

Read³

et al. 2011

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

The understanding of a species' niche is fundamental to the concept of ecology, yet relatively little work has been done on niches in pelagic marine mammal communities. Data collection on the distribution and abundance of marine mammals is costly, time consuming and complicated by logistical difficulties. Here we take advantage of a data archive comprising many different datasets on the distribution and abundance of cetaceans from Nova Scotia through the Gulf of Mexico in an effort to uncover community structure at large spatial scales (1000s of km). We constructed a multivariate ordination of the species data, tested for group structure that might exist within the ordination space, and determined how these groups might differ in environmental space. We examined 3 biogeographic regions: the oceanic waters north and south of Cape Hatteras, NC, and the Gulf of Mexico. North of Hatteras, we found 2 main groups split along a temperature and chlorophyll gradient, with most piscivores being found in cooler, more productive waters of the continental shelf, and most teuthivores being found farther offshore in warmer, less productive waters at the shelf break (200 m isobath). South of Hatteras, we found 3 groups, with the largest group being in warmer, lower chlorophyll waters that are closest to shore. In the Gulf of Mexico, we found 7 groups arrayed along a bottom depth gradient. We also tested the effect of taxonomically lumping different beaked whale species on ordination results. Results showed that when beaked whales were identified to the species level, they clustered out into distinct niches that are separate from those of other Odontocete groups. These results add to an increasing understanding of wildlife habitat associations and niche partitionings in the community structure of pelagic species, and provide important baseline information for future population monitoring efforts. KEY WORDS: Cetaceans · Group contrast Mantel test · Nonmetric dimensional scaling · Multivariate ordination · Northwest Atlantic OceanResale or republication not permitted without written consent of the publisher

show abstract

Improving Management of Overlapping Bottlenose Dolphin Ecotypes Through Spatial Analysis and Genetics

Cited by 80 publications

References 20 publications

High gene flow in oceanic bottlenose dolphins (Tursiops truncatus) of the North Atlantic

High gene flow in oceanic bottlenose dolphins (Tursiops truncatus) of the North Atlantic

Small dolphins in a small sea: age, growth and life‑history aspects of the Black Sea common bottlenose dolphin Tursiops truncatus

Community structure in pelagic marine mammals at large spatial scales

Contact Info

Product

Resources

About