Writer-by-the-Sea   >  Portfolio   >  Smith River

 Smith River Project > Genetic Concerns

Chapter 5 -- Anadromous Salmonids and Their Habitats (continued)

Genetic Concerns

Genetic composition of anadromous fisheries stocks has developed over millennia to match the unique fluctuating conditions of each particular river system. Beginning in the 1930s, salmonid eggs, fry, or fingerlings were often transplanted to the Smith River from other watersheds. This has presumably altered the genetic composition of native fish and possibly reduced the attunement of native stocks to their home river system. Because introduced stocks usually have lower survival rates than native stocks, inter-breeding of native and introduced stocks may have temporarily or permanently lowered the survival rate of native stocks. This perhaps makes their survival less certain (Sedell and Luchessa 1981). Others state that planted stocks did not become permanently established in the Smith River and that remaining stocks are predominantly native (McCain et al. 1995). Apart from any effects on the gene pool, hatchery fish can also hurt native stocks by competing for food and cover, spreading disease, and increasing the number of predators.


  Photo gallery   Global effort to end poverty