Assessing common bottlenose dolphin ( Tursiops truncatus ) population structure in Mississippi Sound and coastal waters of the north central Gulf of Mexico

Author(s):  
Nicole L. Vollmer ◽  
Patricia E. Rosel ◽  
Keith D. Mullin ◽  
Lori H. Schwacke ◽  
Lance P. Garrison ◽  
...  
Zootaxa ◽  
2018 ◽  
Vol 4379 (3) ◽  
pp. 448
Author(s):  
SOPHIA M. SÁNCHEZ ◽  
LIAT Y. GOLDSTEIN ◽  
NORMAN O. DRONEN

Cobbold (1858) established Diphyllobothrium Cobbold, 1858 with the description of Diphyllobothrium stemmacephalum Cobbold, 1858 from the common harbor porpoise, Phocoena phocoena (Linnaeus) (Phocoenidae), from the North Sea off Scotland. Diphyllobothrium stemmacephalum typically has been reported from a number of Phocoenidae and Delphinidae hosts from a variety of localities: common harbor porpoise from the northern Atlantic Ocean, Baltic Sea and Black sea (e.g. Cobbold, 1858; Delyamure 1955; Delyamure 1968; Delyamure 1971; Delyamure et al. 1985; Anderson, 1987); bottlenose dolphin, Tursiops truncatus (Montagu), from the Gulf of Mexico (Ward & Collins 1959), the Black sea (Delyamure et al. 1985); common harbor porpoise off Newfoundland (Brattey & Stenson 1995), the Black Sea (Krivokhizin & Birkun 1994 [see Yera et al. 2008]), off Denmark (Herreras et al. 1997); long-finned pilot whale, Globicephala melas [Traill], North Atlantic off Faroe Island (Balbuena & Raga 1993); Atlantic white-sided dolphin, Lagenorhynchus acutus [Gray], off Massachusetts (Olson & Caira 1999). 


Author(s):  
Ruth H. Leeney ◽  
Caroline R. Weir ◽  
Pierre Campredon ◽  
Aissa Regalla ◽  
Jeff Foster

There is a paucity of information on the cetacean fauna of Guinea-Bissau in West Africa. We compiled records published in the literature and novel unpublished sighting data (2008–2014) to examine the occurrence and distribution of cetacean species. At least 10 species were verified to occur in Guinea-Bissau waters, of which eight were documented from a small number of sightings, whaling captures or skeletal remains. By far the most frequently recorded species were the common bottlenose dolphin (Tursiops truncatus) (N = 146) and the Atlantic humpback dolphin (Sousa teuszii) (N = 110). These two species were sympatric in distribution, both being found throughout coastal waters from the northern regions of Canal de Jeta and Rio Mansôa south to the Rio Cacine and around the Arquipélago dos Bijagós. However, differences were apparent in their finer-scale distribution and in the distance of sightings from shore, with bottlenose dolphin sightings generally occurring further from shore (and especially in the region of the Canal do Gêba) than Atlantic humpback dolphins. Sightings indicate that both species likely inhabit Guinea-Bissau waters throughout the year. Dedicated systematic cetacean survey work is urgently needed in coastal Bissau-Guinean waters in order to ascertain the abundance, spatio-temporal distribution, population structure and causes of mortality of bottlenose and Atlantic humpback dolphins, particularly given the Vulnerable conservation status of the latter species. Clarification of the status of cetaceans in offshore waters requires survey effort throughout the Guinea-Bissau EEZ.


PLoS ONE ◽  
2017 ◽  
Vol 12 (7) ◽  
pp. e0181179 ◽  
Author(s):  
Errol I. Ronje ◽  
Kevin P. Barry ◽  
Carrie Sinclair ◽  
Mark A. Grace ◽  
Nélio Barros ◽  
...  

2020 ◽  
Vol 2020 (19) ◽  
pp. 103-107
Author(s):  
Oksana Savenko ◽  
◽  

Piebaldism is one of three types of hypopigmentation of animals, when some areas on the skin have no pigments. Anomalously white cetaceans are rare, although they have been reported in more than 20 different cetacean species, including the common bottlenose dolphin, which in the Black Sea is recognized as an endangered endemic subspecies — the Black Sea bottlenose dolphin (Tursiops truncatus ponticus Barabash-Nikiforov, 1940). Its main habitat in the north-western Black Sea region is the coastal waters, however, these dolphins also occur offshore. Thirty cases of anomalously white bottlenose dolphins have been reported from the Black Sea, which were unevenly distributed, and only a few sightings have been reported from the north-western Black Sea. Cetacean observations were conducted in the Ukrainian part of the north-western Black Sea waters in April 2017, onboard the research vessel "Auguste Piccard". All encountered cetaceans were photographed, and individual distinctiveness of dorsal fin images was used for their photo-identification. On 13 April 2017, four groups of up to four individuals of bottlenose dolphins were encountered in the same area at a distance of 61 km south of Odesa (34 km from the nearest coast). The depth at the observation site was about 20 m. The initially observed type of dolphins’ behavior was feeding. However, two groups changed their behavior and followed the vessel by 5–6 individuals for approximately 18 minutes. The joint group consisted of adults and one juvenile individual. Among the adults, there was one piebald specimen with white patches on its dorsal fin, peduncle, and tail fluke. The piebald dolphin was photographed and photo-identified. Our research has shown that piebald Black sea bottlenose dolphins occur not only in the coastal waters, but also in offshore waters of the north-western Black Sea. However, the frequency of such hypopigmentation in local populations remains unknown. Further intensive photo-identification and genetic sampling of local stocks of the Black Sea bottlenose dolphins are necessary for the assessment of their population genetic structure and its divergence.


2017 ◽  
Vol 98 (5) ◽  
pp. 1055-1063
Author(s):  
Tom Brereton ◽  
Duncan Jones ◽  
Keith Leeves ◽  
Kate Lewis ◽  
Rachel Davies ◽  
...  

In this study photo-identification data were used to better understand movements, population structure and abundance of common bottlenose dolphin (Tursiops truncatus) in south-west England and surrounding waters, to inform conservation efforts. A catalogue of 485 photographic sightings of 113 individuals was compiled from ~150 common bottlenose dolphin encounters made on 87 dates between March 2007 and January 2014. From these and other data, three likely sub-populations were identified in the western English Channel, demarcated by bathymetry and distance to land: (1) south-west England – inshore Cornwall to Devon, (2) offshore English/French waters and (3) inshore France from Brittany to Normandy. Maximum abundance estimates for south-west England coastal waters, using two methods, ranged between 102 and 113 (range 87–142, 95% CL) over the period 2008–2013, likely qualifying the region as nationally important, whilst the yearly maximum was 58 in 2013. The population was centred on Cornwall, where 19 well-marked animals were considered ‘probable’ residents. There were no ‘probable’ resident well-marked individuals found to be restricted to either Devon or Dorset, with animals moving freely within coastal areas across the three counties. Movements were also detected within offshore English waters and French waters (from other studies) of the western English Channel, but no interchange has as yet been detected between the three regions, highlighting the possible separation of the populations, though sample sizes are insufficient to confirm this. Given the findings, south-west England waters should be considered as a separate management unit requiring targeted conservation efforts.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4589 ◽  
Author(s):  
Rosa de los Ángeles Bayas-Rea ◽  
Fernando Félix ◽  
Rommel Montufar

The common bottlenose dolphin, Tursiops truncatus, is widely distributed along the western coast of South America. In Ecuador, a resident population of bottlenose dolphins inhabits the inner estuarine area of the Gulf of Guayaquil located in the southwestern part of the country and is under threat from different human activities in the area. Only one genetic study on South American common bottlenose dolphins has been carried out to date, and understanding genetic variation of wildlife populations, especially species that are identified as threatened, is crucial for defining conservation units and developing appropriate conservation strategies. In order to evaluate the evolutionary link of this population, we assessed the phylogenetic relationships, phylogeographic patterns, and population structure using mitochondrial DNA (mtDNA). The sampling comprised: (i) 31 skin samples collected from free-ranging dolphins at three locations in the Gulf of Guayaquil inner estuary, (ii) 38 samples from stranded dolphins available at the collection of the “Museo de Ballenas de Salinas,” (iii) 549 mtDNA control region (mtDNA CR) sequences from GenBank, and (iv) 66 concatenated sequences from 7-mtDNA regions (12S rRNA, 16S rRNA, NADH dehydrogenase subunit I–II, cytochrome oxidase I and II, cytochrome b, and CR) obtained from mitogenomes available in GenBank. Our analyses indicated population structure between both inner and outer estuary dolphin populations as well as with distinct populations of T. truncatus using mtDNA CR. Moreover, the inner estuary bottlenose dolphin (estuarine bottlenose dolphin) population exhibited lower levels of genetic diversity than the outer estuary dolphin population according to the mtDNA CR. Finally, the estuarine bottlenose dolphin population was genetically distinct from other T. truncatus populations based on mtDNA CR and 7-mtDNA regions. From these results, we suggest that the estuarine bottlenose dolphin population should be considered a distinct lineage. This dolphin population faces a variety of anthropogenic threats in this area; thus, we highlight its fragility and urge authorities to issue prompt management and conservation measures.


Author(s):  
ANTONELLA ARCANGELI ◽  
ROBERTO CROSTI ◽  
ILARIA CAMPANA ◽  
LARA CAROSSO ◽  
MARTINA GREGORIETTI ◽  
...  

A pilot study, using the dataset from the research network ‘FLT Med Net’, which regularly monitors transborder regions in the Mediterranean Sea using ferries as platform for systematic surveys, was undertaken to assess common bottlenose dolphin range and population trends within the Natura 2000 EU marine site “Tutela del Tursiops truncatus”. The site was recently designated by the Tuscany Region (Italy) within the requirement of the EU Habitats Directive. In order to evaluate the conservation status of bottlenose dolphin according to the surveillance scheme of the Directive, two six-year periods (2007-2012; 2013-2018) were compared to assess trends in distribution-occurrence (range); Sightings Per Unit of Effort and Density (population). In total, 18146 NM were surveyed along two fixed transects, recording 90 sightings of Tursiops truncatus and a total of 268 specimens. Between the two periods, slight but not statistically significant differences were assessed, with decreasing trend in range and population  of the species; no variation was detected in mean group sizes. Travelling was the most common behaviour, and juveniles were present in 20% of the sightings, concentrated during spring and summer. The consistent FLT Med Net dataset was found to be appropriate to evaluate important parameters for the assessment of trends in the conservation status of Tursiops truncatus at the Natura2000 site scale. 


Sign in / Sign up

Export Citation Format

Share Document