Selection Breeding of Masu Salmon, Oncorhynchus masou without Parr Marks and Black Spots

Abstract

We discovered 28 masu salmon, Oncorhynchus masou fry without parr marks and black spots among about 3, 000 in 1987. These fry were the progeny of wild fish from the Shokanbetu River in Hokkaido. In September 1988, we obtained about 8, 000 eggs (F₁ generation) fertilized between 3 markless males and 15 normal females. They were reared until the adults as a pilot brood stock at Nanae Fish Culture Experimental Station, Faculty of Fisheries, Hokkaido University. We could find no fish with parr marks in the F₁ generation. In 1991, an F₂ generation was obtained from F₁ parents. Among 44, 517 fry, 0.7 % were markless salmon. Using markless F₂ generation adults, an F₃ generation was obtained, seventy-six % of which had no parr marks or black spots. The markless salmon should be useful for release-recapture studies in the future.