Radio-transmitted electromyogram signals as indicators of swimming speed in lake trout and brown trout

Swimming speed and average electromyogram (EMG) pulse intervals were highly correlated in individual lake trout Salvelinus namaycush (r(2)=0.52-0.89) and brown trout Salmo trutta (r(2)=0.45-0.96). High correlations were found also for pooled data in both lake trout (r(2)=0.90) and brown trout of the Ema stock (r(2)=0.96) and Laerdal stock (r(2)=0.96). The linear relationsh ip between swimming speed and average EMG pulse intervals differed signific antly among lake trout and the brown trout stocks. This successful calibrat ion of EMGs to swimming speed opens the possibility of recording swimming s peed of free swimming lake trout and brown trout in situ. EMGs can also be calibrated to oxygen consumption to record energy expenditure. (C) 2000 The Fisheries Society of the British Isles.