Research objectives are: (1) To determine the smolt status of one-year-old landlocked Atlantic salmon; (2) to compare survival and growth between landlocked and sea-run Atlantic salmon in commercial scale sea-cages; (3) to determine maturity characteristics of landlocked Atlantic salmon grown in sea-cages. To accomplish these objectives, the research will use tests of smoltification including gill Na+-K+ ATPase, plasma thyroxine, and osmolality; comparative rearing trials of landlocked and sea-run salmon in sea-cages; incidence of grilse; hormone profiles in maturing adults; and egg viability. This research would contribute basic and applied knowledge on the physiology and endocrinology of landlocked Atlantic salmon and on their potential for marine culture. Results could be applied to increase the supply of seedstock needed by U.S. growers and thus reduce reliance to imported salmon. A major problem in marine culture of Atlantic salmon (Salmo salar) in the north-eastern United States is the lack of smolts. Diadromous (sea-run) Atlantic salmon are difficult and costly to rear through the pre-smolt stage. Maine has native populations of landlocked Atlantic salmon (S. salar) that reach smolt size in half the time of sea-run smolts at ambient water temperatures. These landlocks may serve as an alternative to sea-run salmon for marine culture.
