Interannual differences in postrelease movements of rehabilitated harbor seal pups (Phoca vitulina richardii) in the Salish Sea
A study published in Marine Mammal Science in June 2020 followed the movements and behavior of rehabilitated harbor seal pups after being released into the Salish Sea. The results suggest that although their movements differ from wild pups that have been weaned, the rehabilitated pups do successfully make the transition.
Adult harbor seal with pup. Photo: Mark Ahlness (CC BY-NC-ND 2.0)
Despite the large number of harbor seals (Phoca vitulina richardii) rehabilitated worldwide, few studies have been conducted on postrelease movement and behavior of rehabilitated harbor seal pups. We compared interannual differences in movements and survival of 24 rehabilitated seal pups released in the Salish Sea in 2010 (n = 10), 2012 (n = 5), 2013 (n = 5), and 2014 (n = 4). We also compared the postrelease movement of these seals to the movement of 10 wild seal pups tracked in the same ecosystem in 2010. Transmission duration, total cumulative distance, and average daily distance varied annually. Maximum linear distance traveled from the release site was similar for the rehabilitated seal groups. Compared to wild seals (n = 10), and consistent with prior studies, rehabilitated pups (n = 24) traveled significantly farther daily and cumulatively than wild weaned pups. Unlike in a prior study in this ecosystem, we found no significant difference between transmission duration in wild and rehabilitated pups.
Sangster S, Haulena M, Nordstrom C, Gaydos JK. Interannual differences in postrelease movements of rehabilitated harbor seal pups (Phoca vitulina richardii) in the Salish Sea. Mar Mam Sci. 2020;1–16. https://doi.org/10.1111/mms.12739
Download the full paper (open access)
Samantha Sangster: Cummings School of Veterinary Medicine,Tufts University, Grafton, Massachusetts; Martin Haulena and Chad Nordstrom: Animal Health Department, Vancouver Aquarium, Vancouver, British Columbia, Canada; Joseph K. Gaydos: SeaDoc Society, UC Davis Karen C. Drayer Wildlife Health Center – Orcas Island Office, Eastsound, Washington
Samantha Sangster, Martin Haulena, Chad Nordstrom, and Joseph K. Gaydos
Marine Mammal Science
Mammals, Species and food webs, Harbor seals
Harbor Seal (Phoca vitulina)