Life-history strategies and protein metabolism in overwintering juvenile Atlantic salmon: growth is enhanced in early migrants through lower protein turnover

The specific growth rate (length) of early migrant juvenile Atlantic salmon Salmo salar was significantly greater than that of delayed migrants in Nov ember and February. However, there were no differences in the fractional ra te of protein synthesis (k(s)) of white muscle tissue between the migrant g roups at any time. Early migrants had significantly greater fractional rate s of protein growth (k(g)) of white muscle in February and significantly lo wer fractional rates of protein degradation (k(d)) in May. These results su ggest that, compared to delayed migrants, Atlantic salmon adopting the stra tegy of early seaward migration maximize their overwinter growth by minimiz ing their rate of protein turnover. (C) 2000 The Fisheries Society of the B ritish Isles.