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 November and February. However, there were no differences in the fractional rate of protein synthesis ( k_s ) of white muscle tissue between the migrant groups at any time. Early migrants had significantly greater fractional rates of protein growth ( k_g ) of white muscle in February and significantly lower fractional rates of protein degradation ( k_d ) in May. These results suggest that, compared to delayed migrants, Atlantic salmon adopting the strategy of early seaward migration maximize their overwinter growth by minimizing their rate of protein turnover.