VIABILITY AND FRESH-WATER PERFORMANCE OF ATLANTIC SALMON (SALMO-SALAR) X BROWN TROUT (SALMO-TRUTTA) TRIPLOID HYBRIDS

Survival to initiation of feeding and early freshwater growth were measured for both diploid (2N) and triploid (3N) Atlantic salmon (Salmo salar) and 2N and 3N hybrids between female Atlantic salmon and male brown trout (Salmo trutta) to evaluate the triploid hybrid's potential for commercial culture. Crosses were made in 1990 and 1991 and triploidy was induced by heat shock. Average survival to initiation of feeding generally did not differ among the 2N Atlantic salmon and hybrids within years, nor between the 3N crosses within years. Average survival to initiation of feeding of the 3N Atlantic salmon and hybrids relative to the corresponding 2N crosses was reduced by 2 and 9%, respectively, in 1990, and by 55 and 62%, respectively, in 1991. Five freshwater growth trials were conducted to compare the different crosses. Results indicated no consistent differences in relative growth rates, although the hybrids demonstrated greater variability in growth at age 0+.