To Keep or Not to Keep: Utilizing Bycatch in the Alaskan King Crab Fisheries

Bycatch of king crabs (and other crab species) in the Bering Sea is usually considered to be a problem of trawl fisheries, but bycatch in directed trap fisheries is several orders of magnitude greater than in non-direct trawl fisheries. Trap bycatch is a consequence of selective harvest, due to the imposition of minimum size limits as well as species restrictions. Selective harvest can have detrimental effects on king crab populations including altered size distributions, reduced size at maturity, and reduced reproductive capacity. Even discounting mortality, which is generally small, it represents a loss to the fishery from wasted effort, as well as to future recruitment.  Bycatch is also augmented by ghost fishing due to lost traps, and multiple recapture of discarded crabs.  For consistency with Ecosystem Based Management, alternative goals for king crab management should include maintenance of size structure, setting of quotas across a greater diversity of size groups, and inclusion of bycatch as part of the solution.  This could be achieved by standardizing trap design and allowing (or mandating) that all discards be kept and utilized.  Any short-term impacts to the processing and marketing segments will likely be offset by greater long-term improvements to crab populations.