Search

The harbor porpoise ( Phocoena phocoena (L., 1758)) used to be common in Puget Sound, Washington, but virtually disappeared from these waters by the 1970s. We conducted systematic aerial line-transect surveys (17 237 km total effort) for harbor porpoises, with the goal of estimating density and abundance in the inland waters of Washington State. Surveys in Puget Sound occurred throughout the year from 2013 to 2015, and in the Strait of Juan de Fuca and the San Juan Islands (and some adjacent Canadian waters) in April 2015. We used a high-wing, twin-engine Partenavia airplane and four observers (one on each side of the plane, one looking through a belly port, and one recording data). A total of 1063 harbor porpoise groups were sighted. Density and abundance were estimated using conventional distance sampling methods. Analyses were limited to 447 harbor porpoise groups observed during 5708 km of effort during good sighting conditions suitable for line-transect analysis. Harbor porpoises occurred in all regions of the study area, with highest densities around the San Juan Islands and in northern Puget Sound. Overall, estimated abundance for the Washington Inland Waters stock was 11 233 porpoises (CV = 37%, 95% CI = 9 616 - 13 120). This project clearly demonstrated that harbor porpoises have reoccupied waters of Puget Sound and are present there in all seasons. However, the specific reasons for their initial decline and subsequent recovery remain uncertain. [ABSTRACT FROM AUTHOR]

Describing feeding habits of cetaceans is crucial to understanding their feeding strategies and conservation status. Here, both morphological and molecular techniques were employed to identify the stomach contents of 122 finless porpoises ( Neophocaena spp.) in the East China Sea for insight into their short-term feeding habits, and stable isotopes of δ13C and δ15N were used to analyze prey resource use and trophic position as a manifestation of their long-term feeding habits. In total, 33 prey species consisting of 19 teleosts, seven crustaceans, five cephalopods, and two gastropods were identified. In both short- and long-term analyses, teleosts represented primary prey, cephalopods and crustaceans were secondary prey, and gastropods were occasional prey; but the primary prey species composition differs between the short- and long-term diets. The composition of stomach contents showed sexual and age-related variation. This finding is supported by stable isotopic analyses, which indicated the separation of trophic position of adult males, adult females, and young males. In general, finless porpoises prey on species that are primarily caught by fisheries. [ABSTRACT FROM AUTHOR]