Thousands of pounds of Dungeness crab sit in the hold of the Petersburg-based fishing boat F/V Erika Ann, ready for unloading. The fall fishery opened Oct. 1, with the possibility of six million pounds being predicted. However, poor stock health for Alaska red king crab saw that fishery close Oct. 3.
Crab harvests in southeast Alaska this year won't feature the state's historic cash crops of Red King Crabs, as historically low population levels persist in the region, according to Alaska's Department of Fish and Game, which announced the pre-emptive closure of the 2014/2015 fishing season on Oct. 3.
The Southeast Alaska Red King Crab Management Plan directs the department to manage the Southeast Alaska red king crab fishery in accordance with the Alaska Board of Fisheries' "Policy on King and Tanner Crab Resource Management" if the department's estimate of available harvest is below the minimum threshold of 200,000 pounds of legal male red king crab.
Regionally, the biomass estimate did increase from last season, but is still at historically low levels. Five of nine survey areas exhibited poor stock health in this year's stock assessment survey. Four other areas showed improvements in stock health, largely fueled by increasing numbers of non-legal sized, pre-recruit male crabs. The biomass estimates for legal and mature RKC for the Southeast Region are 0.76 million pounds and 1.39 million pounds, respectively, for the 2014/2015 season.
This is virtually the same amount of legal crab estimated in 2013, but a 52 percent increase in the mature male biomass. These legal and mature biomass estimates have also been adjusted to incorporate mark/recapture assessments for seven areas in total. Regional biomass is estimated from eight survey areas and extrapolated to the entire region.
Areas surveyed include Pybus Bay, Gambier Bay, Seymour Canal, Peril Strait, the Juneau area, Lynn Sisters, Excursion Inlet, Port Frederick and Holkham Bay. The estimate of available harvest was determined through a catch-survey analysis (CSA) for all surveyed bays with the exception of Holkham Bay, where the CSA model does not currently allow for a biomass estimate to be produced.
The CSA incorporates department stock assessment survey data from 2014 and prior years, commercial harvest in 2011 and prior years, and port sampling data obtained during landings of commercial harvest. Biomass estimates produced for each survey area were adjusted based on mark/recapture assessments done in the surveyed areas, with additional restratification implemented since 2005 to reduce variance in estimates of population size by adjusting sampling intensity to correspond with variation in survey catch and other factors.
In 2009, the department initiated a collaborative study with the commercial crab industry to ground department pot survey-based biomass estimates using mark/recapture techniques surveying the Lynn Sisters area. The department received both North Pacific Research Board funding and a legislative increment to support this effort. Pybus Bay, Gambier Bay, and Excursion Inlet were surveyed in 2010, and Seymour Canal, Peril Strait, and Port Frederick were completed in 2011. Holkham Bay was completed in 2012. Though all eight areas originally slated for mark/recapture work have been completed, new mark/recapture estimates need to be completed in all eight areas to provide additional data to use in assessing regional red king crab abundance. Fishermen are advised that the department will continue to work collaboratively with industry to repeat mark and recapture experiments in survey areas and continue improvements to red king crab stock assessment in Southeast Alaska.
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