New publication on cetacean occurrence in Onslow Bay

Posted on May 27, 2015

Occurrence, distribution and abundance of cetaceans in Onslow Bay, North Carolina, USA (Full-text PDF)

ANDREW J. READ, SUSAN BARCO, JOEL BELL, DAVID L. BORCHERS, M. LOUISE BURT, ERIN W. CUMMINGS, JENNIFER DUNN, ERIN MEAGHER FOUGERES, LUCIE HAZEN, LYNNE E. WILLIAMS HODGE, ANNA-MARIE LAURA, RYAN J. MCALARNEY, PETER NILSSON, D. ANN PABST

ABSTRACT

In this paper the occurrence, distribution and abundance of cetaceans in offshore waters of Onslow Bay, North Carolina, USA is described. Between June 2007 and June 2010 monthly aerial and shipboard line-transect surveys were conducted along ten 74km transects placed perpendicular to the shelf break. In total 42,676km of aerial trackline (218 sightings) and 5,209km of vessel trackline (100 sightings) were observed. Seven species of cetaceans were observed, but the fauna was dominated strongly by common bottlenose and Atlantic spotted dolphins. Both species were present year-round in the study area. Using photo-identification techniques, five bottlenose dolphins and one spotted dolphin were resighted during the three-year period. In general, the abundance of cetaceans in Onslow Bay was low and too few sightings were made to estimate monthly abundances for species other than bottlenose and spotted dolphins. Maximum monthly abundances of bottlenose and spotted dolphins were 4,100 (95% CI: 1,300–9,400) in May 2010 and 6,000 (95% CI: 2,500–17,400) in March 2009, respectively. Bottlenose dolphins were found throughout the study area, although they were encountered most frequently just off the shelf break.