Entanglement of northern fur seals (Callorhinus ursinus) in marine debris on Tyuleniy Island (Sea of Okhotsk) in 1998-2013

Abstract

The systematic annual observations of the northern fur seal rookery on Tyuleniy (= Robben) Island, Sea of Okhotsk, were started in 1958. Since 1975, all seals entangled in marine debris have been registered. Some of the data on this issue, collected on the island in the late 20th century, were published earlier. This report provides data for the period of completion of the commercial sealing (from 1998 to 2013). During this period, a total of 867 fur seals were observed entangled in marine debris, including 212 bulls, 97 half-bulls, 223 bachelors, and 335 females. The estimated mean annual number of entangled fur seals in 1998-2013 is 1113 individuals. Marine debris was found mainly on the neck and, less frequently, on the head and front flippers of the animals. This included pieces of fishing nets, packaging bands, ropes, fishing lines, and other items of anthropogenic origin.

Keywords: Entanglement; Marine debris; Northern fur seal; Pollution; Sea of Okhotsk; Tyuleniy Island.