Sitka – The Alaska Department of Fish and Game announced Dec. 6 the preliminary guideline harvest level (GHL) for the 2014 Sitka Sound sac roe herring fishery is 17,592 tons based on a 20% harvest rate of a forecast biomass of 87,958 tons.
The department uses an age structured analysis (ASA) model which uses a long time series of abundance and age composition data from department surveys conducted during and following the spring fishery. Herring abundance is estimated using aerial surveys designed to map the length of shoreline receiving spawn, and dive surveys which estimate the density of eggs and the average width of the spawn. The department mapped 61.3 nautical miles of herring spawn in the Sitka Sound area during the spring of 2013, about equal with the recent 10-year average. The estimated post-fishery spawning biomass in 2013 was 82,653 tons and the total harvest was 5,786 tons for a total biomass of 88,439 tons, above the forecast of 76,988 tons. Samples of the spawning herring in 2013 resulted in an age composition of 20% age-3, 9% age-4, 8% age-5, 20% age-6, 16% age-7, and 27% age-8+. The forecast indicates that the spawning stock in 2014 will consist of 12% age-3, 35% age-4, 9% age-5, 7% age-6, 12% age-7, and 25% age-8 and older herring.
The forecast and GHL for the 2014 fishery will be finalized using average weight-at-age from samples obtained in the winter test fishery, to be conducted sometime during late-January or early-February, 2014. The final forecast will be announced in late-February or early-March.
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