The AFSC has conducted an annual longline survey of sablefish and other groundfish in Alaska from 1987 to 2008. The survey is a joint effort involving the AFSC's Auke Bay Laboratories and Resource Assessment and Conservation Engineering (RACE) Division. It replicates as closely as practical the Japan-U.S. cooperative longline survey conducted from 1978 to 1994 and also samples gullies not sampled during the cooperative longline survey.
In 2008, the thirtieth annual longline survey of the upper continental slope of the Gulf of Alaska and eastern Aleutian Islands was conducted. One hundred-forty-eight longline hauls (sets) were completed during 4 June–1 September 2008 by the chartered fishing vessel Alaskan Leader. Sixteen kilometers (km) of groundline were set each day, containing 7,200 hooks baited with squid.
Sablefish (Anoplopoma fimbria) was the most frequently caught species, followed by giant grenadier (Albatrossia pectoralis), shortspine thornyhead (Sebastolobus alascanus), arrowtooth flounder (Atheresthes stomias), and Pacific cod (Gadus macrocephalus). A total of 74,257 sablefish were caught during the survey.
Sablefish, shortspine thornyhead, Greenland turbot (Reinhardtius hippoglossoides), spiny dogfish (Squalus acanthias), and lingcod (Ophiodon elongatus), were tagged and released during the survey. To date, 221,167 sablefish have been tagged during the survey time series with 17,261 recoveries. Length-weight data and otoliths were collected from 2,003 sablefish.
Killer whales (Orcinus orca) took fish from the longline at three stations in the Aleutian Islands region and two stations in the western Gulf of Alaska.
Sperm whales (Physeter macrocephalus) were often present during haulback and were observed depredating on the longline at 18 stations in the eastern Gulf and 3 stations in the central Gulf of Alaska. This is the highest incidence of sperm whale interactions ever encountered during the survey. Occurrence of depredation in the eastern Gulf has ranged from 10% of sampling days that sperm whales were present in 2001 to 90% in 2008.
Several special projects were conducted during the 2008 longline survey. Spiny dogfish and lingcod were tagged with archival temperature/depth tags in the West Yakutat and central Gulf of Alaska regions.
Photographs of sperm whales observed during the survey were taken for contribution to the Southeast Alaska Sperm Whale Avoidance Project (SEASWAP) sperm whale catalog. Yellow Irish lords were sampled for maturity information in the Aleutian Islands to help support sculpin life history studies.
Finally, a 2-day gear experiment was conducted near Yakutat to compare the catching efficiency of standard, hand-baited survey gear to auto-baited gear.
