Prince William Sound Herring Fishery Updates       While every effort is made to keep this page current, there may be delays in the posting of web page updates.  For the most current announcement/news release information please call our 24-hour recorded-message phone at 907-424-7535 or call the Cordova Office at 907-424-3212.

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Prince William Sound Herring Announcement #2

Issued Tuesday, September 30, 2008 - 2:00 p.m.

Based on current herring stock assessment information, the 2008-2009 food and bait fishery and all 2009 spring herring fisheries including the purse seine and gillnet sac roe harvests, the spawn-on-kelp in pound fishery, and the wild spawn-on-kelp harvest are closed. The Prince William Sound herring biomass estimate is below the minimum spawning biomass threshold of 22,000 tons. According to 5AAC 27.365(b) Prince William Sound Herring Management Plan, no fishery may be opened if the estimated spawning biomass is below this threshold level.

Age Structured Assessment (ASA) modeling was used to project the 2009 biomass of Pacific herring. The preliminary PWS herring spawning biomass forecast for 2009 is ~15,000 tons. The preliminary ASA model estimate was calculated using preliminary acoustics data, and the final estimate will be announced after the final acoustics data is available. Hydroacoustic, net sampling, and aerial surveys were conducted in 2008 to assess herring biomass, disease prevalence, age composition, and growth.

Acoustic surveys were conducted during March and April, 2008 with the ADF&G research vessel Solstice and the M/V Auklet, contracted by the Prince William Sound Science Center. The department conducted broad scale surveys in eastern Prince William Sound up to Tatitlek Narrows; north and central Montague Island; and from Sawmill Bay to Whale Bay. Detailed acoustics data were collected on major concentrations of herring in St. Matthews Bay, Port Fidalgo, Two Moon Bay, Whale Bay, and near Bishop Rock. Age composition samples varied by location and sample gear: spawning fish samples (Eastern PWS) were predominately age 4 and age 9, but spawning samples from other locations were predominately younger fish (age 3 and 4). The biomass documented in Whale Bay was mostly juvenile fish (65% age 2).

Herring disease assessment has been included as part of the annual age, sex, and size assessment program the department has completed each spring since 1993. More information on the prevalence of viral hemorrhagic septicemia virus (VHSV) and Ichthyophonus hoferi in the herring population from samples collected in the spring of 2008 will be provided when it becomes available.

Aerial surveys documented a peak biomass estimate of ~10,700 tons of herring versus 770 tons last year (2007), 540 tons in 2006, 4,773 tons in 2005 and 12,305 tons in 2004. The largest biomass estimate (~10,000 tons) was observed in Port Gravina and Port Fidalgo. A total of 33.2 mile-days of spawn were observed in spring 2008, almost double the mile-days observed in 2007. The largest individual spawning event occurred between St. Matthews Bay and Knowles Head with ~14 miles of spawn. Additionally, there was a 5.1 miles of spawn on a single day in the bays of north Montague Island.

The department will collect additional age, sex, and size data along with disease information throughout PWS this fall. Additional updates on the status of the PWS herring population will be announced when new information becomes available.

Prince William Sound Herring Announcement #1

Issued Friday, April 11, 2008 - 2:00 p.m.

PRINCE WILLIAM SOUND HERRING: As announced in September 2007, all herring fisheries in Prince William Sound will remain closed in spring 2008, including the purse seine and gillnet sac roe, the spawn-on-kelp in pounds, and the wild spawn-on-kelp fisheries. The Prince William Sound herring biomass estimate is below the minimum spawning biomass threshold of 22,000 tons. According to 5AAC 27.365(b) Prince William Sound herring management plan, no fishery may be opened if the estimated spawning biomass is below this threshold level.

Age Structured Assessment modeling was used to project the 2008 biomass of Pacific herring. The PWS herring spawning biomass forecast for 2008 is approximately 10,000 tons. Hydroacoustic, net sampling, 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 ADF&G vessel R/V Solstice and the M/V Auklet, contracted by the Prince William Sound Science Center (PWSSC). Broad scale 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. Age composition samples varied by location and sample gear: spawning fish samples (Eastern PWS) were predominately age 8, but samples from other locations were predominately younger fish (age 1, 2, and 3). The department collected additional age, sex, and size data along with disease assessment data throughout PWS during the fall of 2007. The 2007 biomass estimates from the department’s acoustics survey were 10,635 tons (total biomass) and 4,734 tons (spawning biomass). These estimates do not include the data collected by the PWSSC.

Herring disease assessment has been included as part of the annual age, sex, and size assessment the department has completed each spring since 1993. Disease sampling in 2002 documented a viral hemorrhagic septicemia virus (VHSV) prevalence of 14%. Although this did not appear to seriously impact the adult population, it may have increased mortality of juveniles. Also, the prevalence of Ichthyophonus hoferi increased significantly between 2002 (14%) and 2005 (25%). In March and April of 2007, the department examined herring for prevalence of focal skin reddening and the pathogen I.hoferi. Prevalence of focal skin reddening associated with viral hemorrhagic septicemia virus (VHSV) was low; however, prevalence of I. hoferi was high (25%) and is consistent with the increasing age of the predominant 1999 age class. Additional disease sampling was conducted during the fall of 2007.

Evidence is increasing that both VHSV and I. hoferi may occur in approximately 4-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 versus 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 PWS, 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 in spring 2008, the department has conducted broad scale boat surveys of eastern and southwestern Prince William Sound and northern Montague Island. Acoustics data have been collected on herring schools in St. Matthews Bay, Two Moon Bay, Port Fidalgo (between Fish Bay and Irish Cove), Whale Bay, and near Bishop Rock (Shelter Bay area). Small spawning events have been documented from boat and aerial surveys in Simpson Bay, Sheep Bay, Two Moon Bay, between St. Matthews Bay and Red Head, and in Tatitlek Narrows. Samples for age, sex, and size were collected in Simpson Bay, St. Matthews Bay, between Hells Hole and Porcupine Point, Port Fidalgo, Whale Bay, and near Shelter Bay at Evans Island. Disease assessment samples were collected from fish in Simpson Bay, St. Matthews Bay, Port Fidalgo, and near Shelter Bay.

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. Additional updates on the status of the PWS herring population will be announced when new information becomes available.