Survival and allozyme expression in diploid and triploid hybrids between chum, chinook, and coho salmon

Persistent problems in salmon aquaculture include the mortality of pen-cultured fish due to early maturation of males, the added expense of rearing juveniles of some species in freshwater, and the stress and mortality which can be associated with transferring those same species to sea water. Hybridizations may ameliorate some of these problems, and triploid hybrids frequently survive and growth much better than corresponding diploids. We determined the viabilities and allozyme phenotypes of progeny from diploid and triploid interspecific matings between coho ( Oncorhynchus kisutch), chum ( O. keta), and chinook ( O. tshawytscha) salmon. Allozyme data suggested that coho × chum salmon and chinook × coho salmon matings yielded progeny which were spontaneous gynogens, aneuploids, or possibly incompatible at regulatory loci. Combinations with promising survival included (female parent first) triploid chum × chinook salmon, diploid or triploid coho × chinook salmon, and possibly triploid chinook × coho salmon.