|A note on the southern distribution range of inshore and offshore common bottlenose dolphins Tursiops truncatus in the Southeast Pacific. Scientific Committee document SC/60/SM18, International Whaling Commission, June 2008, Santiago, Chile|
Sanino, G.P.; Van Waerebeek, K. (2008). A note on the southern distribution range of inshore and offshore common bottlenose dolphins Tursiops truncatus in the Southeast Pacific. Scientific Committee document SC/60/SM18, International Whaling Commission, June 2008, Santiago, Chile. International Whaling Commission: Santiago. 6 pp.
Tursiops Gervais, 1855 [WoRMS]; Tursiops truncatus (Montagu, 1821) [WoRMS]; Marine
bottlenose dolphins, Tursiops, Distribution Range, Southeast Pacific, Chile
|Authors|| || Top |
- Sanino, G.P.
- Van Waerebeek, K., more
Both inshore and offshore forms of T. truncates occur off Peru and Chile. The inshore form in Chile is best documented from a single community resident around 29°S, while there is genetic evidence for a large, wide-ranging Peru-Chile offshore population. Oliver (1946) indicated T. truncates for the Gulf of Arauco (at 37°06’S,73°20’W) and despite there was no authentication for half a century it has been the accepted southernmost range in the SE Pacific. However five recent records shift the focus further south to Región de Aisén. In August 2004 two common bottlenose dolphins stranded at Isla Quenu (41°49'.41S,73°9'.01W); next a mother-calf pair was reported inside a fjord at ca. 42°22’S,72°24’W. From habitat and small group size an inshore form was suspected. However, three new sightings of large group size (40-120 individuals) between 43°-45°S in January and December 2007 compelled us to reevaluate the southern distribution range of the species and of each form/ecotype. The bottlenose dolphins were morphologically (very large, stocky bodies with short snout) and behaviourally (large group size) attributable to an offshore form, despite being encountered deep inside fjords of Chilean Patagonia, one at ca. 50 nmiles from open water. All groups were actively attracted to a large RIB and both video and still photographs were collected as voucher material. Our records extend the summer range of T. truncates in the SE Pacific south to 45°05'.597S,73°19'.996W, Magdalena Island, however we expect that additional survey effort may extend this even farther. The population will need to be identified with precision to allow management recommendations.