Chinook salmon are harvested in commercial fisheries in Southeast Alaska (SEAK) waters east of Cape Suckling and north of Dixon Entrance. These fisheries harvest mixed stocks of Chinook salmon, including those originating from Alaska, British Columbia, and the Pacific Northwest. Significant numbers of both hatchery and wild stock Chinook salmon have coded-wire-tags (CWTs) inserted into their heads before they are released from hatcheries or as they migrate to sea. These fish are marked externally by removal of the adipose fin. CWTs are recovered by sampling programs intended to sample a minimum proportion of fishery catches and escapements. Analyses of CWT data provide estimates of fishery exploitation rates and other statistics employed for stock/fishery assessments and planning.
The Pacific Salmon Commission (PSC) technical committees rely upon selected groups of CWT hatchery and wild Chinook and coho as surrogates to estimate impacts on natural stocks. Recent trends in Pacific Northwest towards mass-marking of Chinook salmon smolts released from hatcheries in conjunction with increased hatchery production up to 150 million smolts annually have resulted in a large volume of adipose fin clipped Chinook salmon in SEAK fisheries that do not contain a CWT (No Tags).
The presence of No Tags exceeded 70% of the adipose-clipped fish sampled during the SEAK summer troll fishery in 2015. Alaska Department of Fish and Game (ADF&G) commercial fisheries port samplers have utilized visual sampling of these adipose clipped fish to recover CWTs for over three decades. The escalating presence of No Tags in SEAK fisheries has impacted CWT sample rates by statistical week and area. Although most SEAK Commercial Fisheries port samplers are using electronic tag detection wands to determine if a tag is actually present in the head of adipose fin clipped fish; the No Tag rate is so high that it requires two samplers per sampling event to be efficient at examining adipose clipped Chinook salmon harvested in the SEAK troll fisheries to determine if valid CWTs are present before CWT processing protocols are invoked.
In an effort to increase or maintain CWT sample rates and decrease shipping costs we propose to continue funding port sampling staff in the ports of Craig, Juneau, Pelican, Wrangell, Petersburg, Ketchikan, and Sitka. Southeast Alaska port samplers will use electronic tag detection wands to examine adipose clipped Chinook salmon harvested in the summer Southeast Alaska troll fisheries to determine if valid CWTs are present before CWT processing protocols are invoked. The heads of any positively identified tagged fish will be collected and the tags decoded by ADF&G staff. This will increase sampling rates by decreasing the amount of fish heads to be organised and shipped.