Remarkably low genetic diversity and strong population structure in common bottlenose dolphins (Tursiops truncatus) from coastal waters of the Southwestern Atlantic Ocean

First estimate of common bottlenose dolphin (Tursiops truncatus) (Cetacea, Delphinidae) abundance off Uruguayan Atlantic coast

“…The small population size estimated for bottlenose dolphin inhabiting the Uruguayan Atlantic coast in this study and its very low genetic variation (Fruet et al, 2014) point to its vulnerability to human-induced impacts, as well as to the effect of both environmental and demographic stochasticity. Incidental capture of small cetaceans has been documented as the main factor affecting dolphin populations around the world (Hall et al, 2000; Read et al, 2006).…”

“…Genoves, 2013;Fruet et al, 2014), the fishing-related mortality in southern Brazil could lead to a source-sink effect (Pulliam, 1988;Harrison and Taylor, 1997), potentially affecting the growth rate of the population inhabiting the Uruguayan coast. In this regard, conservation plans should be designed to protect core and adjacent areas to enhance the connectivity between neighbour coastal populations (Fruet et al, 2014).…”

“…Considering the small population size and very low genetic variation (Fruet et al, 2014), the ignorance about its historical abundance, decline in sighting frequency in the Uruguayan estuarine coast, overfishing of some of its prey (Norbis et al, 2006) and the expansion of industrial activities and infrastructures along the Uruguayan coast, precaution (sensu Gray and Bewers, 1996) is advised in order to protect bottlenose dolphins inhabiting the Uruguayan Atlantic coast. It must be demanded that a robust assessment of the potential effects on the viability of bottlenose dolphins and other components of the marine ecosystem is undertaken before decision makers allow for the establishment of additional human impacting activities.…”

Report of the Working Group on Taxonomy and Stock Identity of bottlenose dolphins in the Southwest Atlantic Ocean

“…In addition to the results from osteological analyses, genotypic data Ott et al, 2009;Fruet et al, 2014;Costa et al, 2015), as well as information on color patterns and external morphology of bottlenose dolphins in southern Brazil (e.g. Cremer et al, 2009) and Argentina (Vermeulen and Cammareri, 2009;Goodall et al, 2011), also revealed that the genus Tursiops presents a more complex variation than a simple latitudinal differentiation in the SWAO.…”

“…On the other hand, the genetic diversity, structure and connectivity among six coastal populations of bottlenose dolphins from southern Brazil, Uruguay and central Argentina were recently investigated based on the analyses of microsatellite (16 loci) and mtDNA control region sequences (457bp) (Fruet et al, 2014; Table 3). Levels of nuclear genetic diversity were remarkably low (mean values of allelic diversity and heterozygosity across all loci were 3.6 and 0.21, respectively).…”