Cherry Point Herring Discussion Topics

Transcription

1 Cherry Point Herring Discussion Topics Decline in spawning biomass since 197 s. Spawning timing. Abundance trend compared to rest of Washington and SOG stocks. Age composition. Spawning location distribution. 28 stock size projection. Sargassum muticum distribution. Washington Department of Fish and Wildlife By Kurt Stick

2

3 Cherry Point Herring Stock Spawning Biomass, Year TOTAL SPAWNER BIOMASS FISHERY LANDINGS

4 Cherry Point Herring Abundance: Historical Perspective TIME PERIOD SOURCE INFORMATION ABUNDANCE LEVEL 1 Pre-193 s Chapman et al (1941). The Races of Herring in the State of Washington. Biol. Rpt. No. 38A. Although statistics are lacking reputed to have been one of the best herring producers on any of the spawning localities in Puget Sound. MEDIUM HIGH? 2 Mid-193 s Chapman et al (1941) 3 Mid-195 s Williams (1959). WDF Fisheries Research Papers, Vol. 2, No. 2. At present, the run is so small as to make commercial fishing unprofitable. only spawn regularly from the mouth of Terrell Creek to Point Whitehorn. formerly depleted have regained their productive levels after many years without exploitation. Largest spawnings at Point Roberts and Hale Pass LOW? MEDIUM-HIGH? s to mid-198 s WDFW surveys Mean spawning biomass for = 92 tons. Spawning occurs at Hale Pass, Cherry Point, Birch Point and Point Roberts. 5 Mid-198 s to present WDFW surveys Mean spawning biomass for = 29 tons. Spawning area compressed; most in southern Birch Bay to Point Whitehorn. HIGH LOW

5 (from Gustafson et al. 26)-ESA status review

6 Cherry Point vs. DPS spawner biomass (metric tons) WDFW & DFO data Thousands Thousands Year DPS minus CPT CHERRY POINT

7 Washington Herring Spawning Biomass Cherry Point vs. all other stocks combined, TONS YEAR SAMPLED TOTAL MINUS CHERRY PT CHERRY PT EST. TOTAL MINUS CHERRY PT

8 DOCUMENTED AND PEAK SPAWNING TIMES FOR WASHINGTON HERRING STOCKS =Peak Spawning South-Central Puget Sound Jan Feb March April May June Squaxin Pass Wollochet Bay Quartermaster Harbor Port Orchard-Madison South Hood Canal Quilcene Bay Port Gamble Kilisut Harbor Port Susan Holmes Harbor Skagit Bay North Puget Sound Jan Feb March April May June Fidalgo Bay Samish/Portage Bay Interior San Juan Is. Semiahmoo Bay Cherry Point Strait of Juan de Fuca Jan Feb March April May June Discovery Bay Dungeness/Sequim Bay

9 (DFO data)

10 Spawn dates (day of year) for Cherry Point Herring stock by year YEAR APRIL MAY JUNE SPAWN DATE

11 AGE AGE AGE AGE AGE AGE AGE AGE AGE

12 Cherry Point Herring Stock Mean Age & Length by Year, Year Standard Length (mm) Age (years) Mean Length Mean Age

13 BLAINE Point Roberts 1973 TO 198 BIRCH BAY CHERRY POINT STRAIT OF GEORGIA 1973to198 Spawning Escapement (TONS) LUMMI BAY LUMMI ISLAND

14 BLAINE Point Roberts 1981 TO 1988 BIRCH BAY CHERRY POINT STRAIT OF GEORGIA 1981to1988 Spawning Escapement (TONS) LUMMI BAY LUMMI ISLAND

15 BLAINE Point Roberts 1989 TO 1996 BIRCH BAY CHERRY POINT STRAIT OF GEORGIA 1989to1996 Spawning Escapement (TONS) LUMMI BAY LUMMI ISLAND

16 BLAINE Point Roberts 1997 TO 25 BIRCH BAY CHERRY POINT STRAIT OF GEORGIA 1997 to 25 Spawning Escapement (TONS) LUMMI BAY LUMMI ISLAND

17 BLAINE 23 BIRCH BAY 1,611 TONS CHERRY POINT STRAIT OF GEORGIA 23 Spawning Escapement (TONS) LUMMI BAY Bellingham Bay stations w/o spawn LUMMI ISLAND

18 BLAINE 24 BIRCH BAY 1,734 TONS CHERRY POINT STRAIT OF GEORGIA 24 Spawning Escapement (TONS) LUMMI BAY Bellingham Bay stations w/o spawn LUMMI ISLAND

19 BLAINE Point Roberts 25 2,1 TONS BIRCH BAY CHERRY POINT STRAIT OF GEORGIA 25 Spawning Escapement (TONS) LUMMI BAY LUMMI ISLAND

20 26 2,216 TONS 26 Spawning Escapement stations without Spawn

21 27 2,169 TONS Spawning Escapement Tons Stations without Spawn

22 Cherry Point 28 Herring Stock Size Projection is 2,621 tons. The size of the 28 spawning run was projected from the biomass of the 27 spawning run at zero mortality, the mean annual mortality rate, and the previous 5 year (23-27) mean recruitment as follows: B = W(1 - A) + R where B is the 28 projected stock size; W is the projected 28 biomass (includes growth) of 27 survivors at zero mortality (3,537 tons); _ A is the mean annual natural mortality rate (.6182); _ R is the previous 5 year mean recruitment (1,271 tons).

23 CHERRY POINT HERRING STOCK PROJECTED vs. OBSERVED STOCK SIZE TONS Projection 2,621 tons YEAR PROJECTED OBSERVED