SITKA, Alaska — The Alaska Department of Fish and Game announced the preliminary guideline harvest level for the 2015 Sitka Sound sac roe herring fishery is 8,712 tons.
That's just over half of last year's quota of 16,333 and the lowest expected GHL in more than 10 years.
The preliminary harvest level is based on a 19.7 percent harvest rate of a mature biomass forecast of 44,237 tons, said Dave Gordon, area management biologist. The preliminary GHL is quite a bit below the 10-year average of 13,500, and far below the 2014 catch of 16,957 tons. Gordon said the GHL hasn't been this low since 2003.
Gordon said very low numbers of age-3 recruit herring in the spring fishery contributed to the forecast decline of the mature herring biomass.
"Obviously things have become a little less favorable for herring recruitment in recent years," he said. "It's the lowest recruitment we've seen since the early 1990s. ... It was almost a blank (this spring). That contributed to the population coming in below what we had forecast."
It's a trend the department is seeing in other herring stocks in Southeast, he said.
Samples of the spawning herring in 2014 resulted in an age composition of 1 percent age-3, 39 percent age-4, 10 percent age-5, 8 percent age-6, 15 percent age-7, and 27 percent age-8 and older.
Gordon said the department is keeping its eye on the situation.
"Hopefully this trend of lower recruitment won't continue," he said.
The forecast indicates that the Sitka mature biomass in 2015 will consist of 17 percent age-3 herring, 5 percent age-4, 33 percent age-5, 5 percent age-6, 6 percent age-7, and 34 percent age-8 and older herring.
Gordon explained that the department uses an age structured analysis 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 50 nautical miles of herring spawn in the Sitka Sound area during the spring of 2014, compared to the recent 10-year average of 60 nautical miles.
The estimated post-fishery spawning biomass in 2014 came in at 51,321 tons, with a total harvest of 16,957 tons. Prices were on the low side, at around $180 per ton, Gordon said. "There's only been a few years where it's been this low," he said.
An additional 121 tons was harvested this spring for personal use and test fisheries for a total mature population biomass of 68,399 tons, which was below the forecast of 81,663 tons, he said.
Gordon said the forecast and GHL for the 2015 fishery will be finalized using average weight-at-age from samples obtained in the winter test fishery, to be conducted in late-January or early-February, 2015. The final forecast will be announced in late-February or early-March.
Information from: Daily Sitka (Alaska) Sentinel, http://www.sitkasentinel.com/