Biologists noted that the 2020 forecast uses a 20 percent exploitation rate because the department has greater confidence in the 2019 aerial survey biomass estimate than those of the last three years. The Togiak mature herring population biomass has been estimated by aerial surveys since the late 1970s.
The Alaska Department of Fish and Game (ADG&G) announcement on Dec. 6 said the 2020 forecasted biomass should be similar in size to the 2019 biomass and, like then, be dominated by partially mature age classes (age-6 and age-7 fish).
The forecast percentage composition of the mature population is comprised of mostly age-6 and age-7 fish by both number – 39 percent and 27 percent respectively – and biomass, 33 percent and 27 percent respectively. Projected average weight of the herring in the 2020 harvest is 329 grams. The age-structured assessment (ASA) model was used to forecast the Togiak herring population.
The 2019 preseason biomass forecast for Togiak was 217,548 tons with an exploitation rate of 14 percent, or 30,457 tons, due to three consecutive years of poor aerial surveys and the associated uncertainty. The purse seine season opened on April 16, 2019 with a harvest of 1,310 tons, and with weather conditions better than in previous years the fishing proceeded at a fast pace. ADF&G said the harvest was generally steady all season long, peaking on April 23 with a 4,430-ton purse seine harvest. Participation in the purse seine fishery documented 19 vessels, down from 20 in 2018. The gillnet fishery opened on April 18, and all harvest information remained confidential due to there being only one processor and three harvesters participating.
Projected ex-vessel value of the 2019 Togiak herring fishery was $1.73 million, based on an advance price estimate of $75 a ton, not including any post-season adjustments.