UNIT 13 

 ALASKA SALMON 



plain the 1997 shortfall of sockeye salmon return- 

 ing to Bristol Bay. During May, June, and part of 

 July of 1997 the region experienced unusually 

 warm, calm weather that resulted in high water 

 temperatures. One hypothesis suggested this 

 caused high mortalit}' and changes in migration 

 behavior alter returning salmon entered Bristol 

 Ba\'. Other suggested causes ol the shortlall in- 

 clude changes in freshwater or ocean rearing con- 

 ditions that affected growth and survival of juve- 

 niles or immature adults, increased predation at 

 sea, mterception by other hsheries, disease, and 

 overescapements on spawning grounds in recent 

 years. I he true cause ol the shortlall, which may 

 involve a combination ol many factors, remains 

 unknown. A paramount unanswered question, 

 however, that arises from 1997 Alaska salmon re- 

 turns, including those in Bristol Bay, is whether 

 or not cyclic changes in oceanic environmental 

 conditions have occurred that portends lower sur- 

 vivals and smaller returns lor luture runs. 



Chum Salmon 



Chum salmon (Figure 13-3) are harvested 

 commercially by purse seines, drift and set gillnets, 

 and in large western Alaska rivers by fish wheels. 

 Statewide, over a 27-year period (1970-97), chum 

 salmon have accounted for 9% of Alaska's salmon 

 harvest (Figure 13-3). Over the past 5-year period 

 (1993-97). the annual average chum salmon har- 

 vest across Alaska was 16,800,000 fish, with the 

 1997 harvest slightly below this average at 

 15,600,000 fish (Savikko, 1997). Currendy 60- 

 70% ol the commercially harvested chum salmon 

 occur in Alaska's southeast region where hatcher- 

 ies produce a significant portion ol the catch. 



Chum salmon rims in southwestern and west- 

 ern Alaska, similar to sockeye salmon, were below 

 expectations in 1997 which added to the shortfall 

 hardships in those regions. Management of chum 

 salmon fisheries in western Alaska is complicated 

 by another commercial fishery at False Pass in the 

 Aleutian Islands. Western Alaska chum salmon 

 may spend part ol their ocean lite in the Gull ol 

 Alaska. 1 hese salmon, as maturing adults on their 

 return migration, tunnel through passes between 

 the vMeutian Islands into the Bering Sea. The False 

 Pass fishery, targeted primarily on sockeye salmon 



Landings 

 (x 1.000 t) 



180 - 

 160 - 

 140 - 

 120 - 

 100 - 

 80 - 

 60 - 

 40 - 

 20 - 

 - 



Landings 

 (- 1,000 t) 



Landings 

 (X 1,000,000 

 individuals! 



- 70 



Landings by total individuals 



Landings by total weight 



_L_ 



_L_ 



1980 1985 



Year 



Figure 13-4 



Alaska commercial landings 

 of sockeye salmon, 1970-97, 

 by metric tons (t) and indi- 

 vidual fish. 



Landings 

 |x 1.000,000 

 individuals) 



- 300 



Landings by total individuals 



- 200 



Landings by total weight 



Year 



returning to Bristol Bay, must be managed to not 

 overharvest chum salmon destined lor the 

 Kuskokwim and Yukon Rivers in western Alaska. 

 Chum salmon in western Alaska are an important 

 part ot commercial fisheries in that region and a 

 significant subsistence resource for local residents. 



Figure 13-5 



Alaska commercial landings 

 of chum salmon, 1970-97 by 

 metric tons (t) and indi- 

 vidual fish. 



