Wednesday, March 29, 2017

Togiak Herring Sac Roe Harvest Set

Harvest allocations for the 2017 Togiak, Alaska, herring sac roe fishery are set at 22,943 tons, with 19,060 tons, or 70 percent for the purse seine vessels, and 6,883 tons, or 30 percent for gillnet harvesters.

The spawn-on-kelp harvest allocation was set at 1,500 tons and the Dutch Harbor food and bait allocation at 1,727 tons.

Biologists with the Alaska Department of Fish and Game (ADF&G) said that the allocation decision, which is usually based on the spawning biomass forecast, this year is based on the average spawning biomass for all years for which they have data, 1978 -2015, less 10 percent in order to be conservative.

Traditionally the department has used an age structured assessment model to forecast the spawning biomass of Togiak herring, which requires estimates of the spawning biomass as well as estimates of the age composition of the spawning biomass and the harvest, ADF&G biologists said on March 28.

The Pacific herring spawning biomass for the Togiak District was not estimated in 2016 nor was any estimate made of the age composition of the 2016 harvest due to state budget cuts, hence the decision to use data averages, they said.

The Bristol Bay Herring Management Plan sets a maximum 20 percent exploitation rate for Togiak District stock. Based on the forecast of 130,852 tons, 26,170 tons of herring will be available for harvest this year.

The management strategy for the Togiak herring fishery is designed to provide for maximum sustained yield. This year the sac roe fisheries will again be managed to maximize product quality through long openings, which allow permit holders to make smaller sets and harvest the highest quality fish, biologists said. Long openings also allow processors to have flexible control of harvest volume so that holding time between harvest and processing is optimal.

Based on a preseason poll, processing capacity is expected to be about 2,150 tons a day. The poll also indicates that four processors will participate in the Togiak sac roe herring fishery with a fleet size of 16 gillnet and 19 purse seine vessels.

For the last decade, ADF&G has opened the herring fishery as soon as the threshold biomass of 35,000 tons has been documented and will use this strategy again in 2017. The strategy allows individual companies to maximize their processing capacity and decide what quality fish is suitable for their individual markets.

ADF&G uses a sea surface temperature model based on temperatures near Unalaska to predict Togiak herring run timing. Based on that model, the fishery should commence around the first week of May, but harvesters and processors are cautioned that this timing model has not performed very well the last couple of years, biologists said.

The department has secured funds sufficient to fly aerial surveys and process herring for age, sex and length samples, which will allow staff to resume use of the age structured assessment model for forecasting herring biomass, biologists said.

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