Table 1. -General life history features of the five species of Pacific salmon in Alaska (Exceptions 

 to these general descriptions occur frequently) 



'Weight of whole or round fish. Source: Int. North Pac. Fish. Comm., Bull. 12, p. 48. 



Food and Growth 



Pink salmon fry grow slowly while they are buried in 

 the streambed and are just over 1 inch long when they 

 migrate to sea. While in the streambed, they obtain nour- 

 ishment from the yolk of the egg, which contains a bal- 

 anced "diet" of protein, carbohydrates, vitamins, and 

 minerals. Growth increases rapidly after the fish reach 

 the sea and its abundant supply of plankton. Pink salmon 

 select their food by sight and swallow it whole. As they 

 grow larger, they feed on progressively larger animals, 

 until squid and other fish are included in their diet. In 

 the extensive estuaries of southeastern Alaska, they may 

 reach a length of 6 to 9 inches before they move into 

 the open ocean. When they return to fresh water several 

 months later, their usual average length is about 20 inches, 

 and their average weight is about 4 pounds. Mature pink 

 salmon do not feed in fresh water. 



Migrations 



Pnik salmon fry emerge from the gravel at night and 

 begin their migration to the sea. When the distance to 

 the sea is short, they reach the estuary of the stream be- 

 fore dawn. In the first few days in the estuary they form 

 schools near the surface of the water and migrate along 

 shore. At this stage they move with surface currents and 

 are carried out of the estuary into the ocean in a few 

 days to several weeks. 



It is not known how salmon are able to find their way 

 from the estuary to the ocean feeding grounds and to 

 return to their home stream. According to one theory, 



they continue to move more or less passively with the 

 prevailing surface currents, which carry them in a roughly 

 circular path out into the North Pacific Ocean and back 

 toward their home stream. Most biologists believe that as 

 the fish approach the coast again, a keen sense of smell 

 and a good memory enable them to find their home 

 stream by its characteristic odors. This theory does not 

 explain, however, how those American and Asian salmon 

 stocks that intermingle at sea are able to find their way 

 back to their home continents. 



ECONOMIC IMPORTANCE 



Salmon fishing is the largest commodity industry in 

 Alaska, and pink salmon is the most valuable species 

 (table 2). 



Most pink salmon are caught in coastal waters by 

 purse seiners (fig. 5), but a small percentage of the com- 

 mercial catch is taken by gill nets. Commercial trollers 

 and sport fishermen catch a few pink salmon while fish- 

 ing for Chinook and coho salmon. The fish are generally 

 canned in shore-based plants and then shipped to Seattle, 

 Washington, for distribution to world markets. By- 

 products of salmon canning have gained commercial 

 importance in Alaska in the past few years. The eggs of 

 all species are processed into caviar and fish bait and the 

 heads and viscera, which were formerly discarded, are 

 now frequently processed into pet food. The annual 

 value for these products has been several million dollars. 



