More accurate improvement of immature state criteria for chum and sockeye salmons
First data have been obtained on structural peculiarities of gonads and chemical composition of gonad content (fat, water, proteins, mineral substances) of immature females and males of chum and sockeye salmons both persisting in mixed aggregations jointly with mature individuals undertaking prespawning migrations. The criterion of immature state of gonads of chum and sockeye salmons suggested is: for the females - the index of water content in gonads 70% at least, and for males - the index of the content of mineral substances less than 2,0% (chum salmon) and less than 3,0% (sockeye salmon). Some corrections and additions have been provided on the base of new data of histological and biochemical researches into the identification table of immature fish currently existing.