FIRST DIET DESCRIPTION OF THE HARBOR SEAL (PHOCA VITULINA) IN THE NORTHWEST CORNER OF THE OLYMPIC PENINSULA, WASHINGTON STATE

Abstract

Abstract Harbor Seals (Phoca vitulina) are widespread and abundant predators in Washington State and their diet is of interest given their potential impact on fish species of concern. Although the diet of this species has been well described, no data exist for most of the Pacific coast along the Olympic Peninsula and the Strait of Juan de Fuca. Here, we provide diet data (via DNA metabarcoding and hard parts) of male and female Harbor Seals from the northwestern coast of the Olympic Peninsula and the western Strait of Juan de Fuca, based on 59 scats collected during December 2020–March 2021. Despite the difficulty in collecting usable scat for hard-parts analysis during the winter months, we were able to determine diet in all collected scats via DNA metabarcoding, highlighting the value of this technique. Based on DNA metabarcoding, the species most frequently consumed by Harbor Seals were Lingcod (Ophiodon elongatus), Pacific Herring (Clupea pallasii), Kelp Greenling (Hexagrammos decagrammus), and Giant Pacific Octopus (Enteroctopus dofleini). Although based on a small sample size, this prey composition differs from that of other sites in the state, supporting the view of Harbor Seals as opportunistic central-place foragers that consume locally and seasonally available prey. Male and female Harbor Seals also appeared to differ in their diet, although the small sample size of this study limits our ability to make a direct comparison. Our results highlight the need for additional studies in the Olympic Peninsula to fully describe the diet of these predators as well as variations among seasons and between sexes.