Swimming performance, oxygen consumption and excess post-exercise oxygen consumption in adult transgenic and ocean-ranched coho salmon

Routine oxygen consumption (MO2) was 35% higher in 1 day starved and 21% higher in 4 day starved adult transgenic coho salmon Oncorhynchus kisutch relative to end of migration ocean-ranched coho salmon. Critical swimming speed (U-crit) and MO2 at U-crit (MO2max) were significantly lower in 4 day starved transgenic coho salmon (1.25BLs(-1); 8.79mg O-2 kg(-1) min(-1)) compared to ocean-ranched coho salmon (1.60 BLs(-1): 9.87 mg O-2 kg(-1) min(-1)). Transgenic fish swam energetically less efficiently than ocean-ranched fish, as indicated by a poorer swimming economy at U-crit (MO2max U-crit(-1)). Although MO2max was lower in transgenic coho salmon. the excess post-exercise oxygen consumption (EPOC) measured during the first 20 min of recovery was significantly larger in transgenic coho salmon (44.1 mg O-2 kg(-1)) compared with ocean-ranched coho salmon (34.2 mg O-2 kg(-1)). which had a faster rate of recovery. (C) 2003 The Fisheries Society of the British Isles.