Marine behavior and dispersal of an important subsistence fish in Arctic Alaska, the Dolly Varden

摘要

In Arctic Alaska the anadromous char, Dolly Varden Salvelinus malma is a highly important subsistence fish to local residents living subsistence-based lifestyles. While in the ocean, very little is known about the marine ecology of Dolly Varden. Therefore, to examine this species' marine habitat occupancy, dispersal, and behavior, we attached pop-up satellite archival tags (PSATs) to Dolly Varden (n = 52) outmigrating from a river, which flows into the Arctic Ocean. Seven tagged fish demonstrated the first documented northwesterly dispersal to offshore areas of the Russian Chukchi Sea. While at sea, these fish demonstrated transits of 30-60 km.day(-1), affinity for the first 5 m of the water column, and diel patterns in depth occupancy, while experiencing a thermal environment of generally 3-7 degrees C. Eight other fish likely occupied nearshore waters of northwestern Alaska. These nearshore dispersers all experienced highly fluctuating daily temperatures (0-15 degrees C), shallow depths (6 m), and appeared to quickly transit in a southerly direction. Because of its ability to rapidly transit broad areas of the Outer Continental Shelf, in addition to its frequent occupation of shallow water, Dolly Varden may be exposed to increased emerging human activities in the Arctic Ocean, such as hydrocarbon development and shipping.