Herring fishery stays closed for 13th year running

JOY LANDALUCE

April 18, 2008 at 10:23AM AKST

There will be no herring fishing in the Prince William Sound this spring.

The announcement by the Alaska Department Fish and Game on April 11 came as no surprise to herring fishermen, who have faced intermittent bans for 19 years.

Fish and Game banned herring fishing in Prince William Sound after the Exxon Valdez oil spill in 1989, to reduce the risk of contaminated catches, due to the significant number of herring that were gathering in oiled waters to spawn.

It was banned again from 1993-96 and from 1996 through last year.

Each ban halted local fishing industries, most recently valued at about $7 million.

Last week’s announcement stated that all herring fisheries in Prince William Sound, including the purse seine and gillnet sac roe, the spawn-on-kelp in pounds, and the wild spawn-on-kelp fisheries, will remain closed in this spring.

The Sound herring biomass estimate of 10,000 tons is below the minimum spawning biomass threshold of 22,000 tons. According to Sound’s herring management plan, no fishery may be opened if the estimated spawning biomass is below this threshold.

Modeling was used to project the 2008 biomass of Pacific herring. Sampling using nets and hydroacoustic and aerial surveys were conducted in 2007 to assess herring biomass, disease prevalence, age composition and growth.

In March and April 2007, acoustic surveys were conducted with the Department of Fish and Game vessel R/V Solstice and the M/V Auklet, contracted by the Prince William Sound Science Center, according to Fish and Game’s update.

Surveys were conducted in eastern Prince William Sound up to Tatitlek Narrows; north and central Montague Island; around Green Island, and from Sawmill Bay to Whale Bay.

Detailed acoustics data were collected on major concentrations of herring in Two Moon, Landlocked, Olsen, St. Matthews, and Sawmill bays, and between St. Matthews Bay and Red Head.

According to the Fish and Game update, the age composition samples varied by location and sample gear.

Spawning fish samples within the Eastern portion of the Prince William Sound were predominately 8 years old, but samples from other locations showed younger fish. The department collected additional age, sex, and size data along with disease assessment data throughout Sound last fall.

The 2007 biomass estimates from the department’s acoustics survey were 10,635 tons of total biomass and 4,734 tons of spawning biomass.

The update cited evidence that both viral hemorrhagic septicemia virus and I. hoferi may occur in approximately four-year cycles. The last I. hoferi peak was in 2001, and prevalence of I. hoferi is positively correlated with age.

Therefore, there may have been increased mortality in older age groups from I. hoferi in 2005, 2006 and 2007. If this trend continues, mortality of the predominant age class may increase significantly.

The department will continue to monitor these disease indices this spring.

Aerial surveys documented a peak biomass estimate of 770 tons of herring in 2007 vs. 540 tons in 2006, 4,773 tons in 2005 and 12,305 tons in 2004.

In 2007, an estimated total of 1,615 tons of herring were seen throughout the Sound, with the largest estimate of 350 tons observed in Port Gravina. A total of 18.3 mile-days of spawn were observed in spring 2007, the second lowest since 1973.

The largest spawning events occurred between Hells Hole and Red Head with 2.8 miles of spawn followed by 1.75 miles in Snug Corner and 1.2 miles in Drier Bay.

So far this spring, the department has conducted boat surveys of eastern and southwestern Prince William Sound and northern Montague Island.

The regular spring herring sampling is currently being conducted in tandem with aerial and hydroacoustic surveys. The department is collecting age, sex, size, disease, and stock identification information.

On the Web:

Prince William Sound Herring Fishery Updates, at www.cf.adfg.state.ak.us/region2/finfish/herring/pws/pwsupd08.php

Joy Landaluce can be reached at (907) 424-7181.