CS15 Fish
Date: Tuesday, June 11, 2002
Location: Poster Session - VCC
 
WagnerGN, University of British Columbia, Vancouver, Canada, wagnerglenn@hotmail.com
McKinley, R, S, University of British Columbia, Vancouver, Canada, mckin@interchange.ubc.ca
Bjorn, P, A, The Norwegian Collage of Fishery Science, Tromso, Norway, paalab@nfh.uit
Finstad, B, , The Norwegian Institute for Nature Research, Trondheim, Norway, finstad@ninatrd.ninaniku.no
 
PHYSIOLOGICAL IMPACT OF SALMON LICE ON THE SWIMMING PERFORMANCE OF ATLANTIC SALMON
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The effect of increased lice numbers on host cardiovascular parameters and swimming ability has yet to be examined. Fish were infected with moderate (0.13 lice/g), and low (0.02 lice/g) levels of lice. Once lice reached adult stages, the ventral aorta of each fish was fitted with a Doppler cuff in order to measure cardiac output, heart rate and stroke volume during swim testing. Critical swimming speeds of moderately infected fish (2.10 bl/s) declined significantly (p < 0.05) compared to low-infection fish (2.43 bl/s) and controls (2.64 bl/s). Unlike controls and low-infection fish, the heart rates of moderately infected fish did not increase significantly at critical swimming speed (62.7 beats/min) compared to resting levels (57.7 beats/min). Chloride levels of moderately infected fish (184.4 mg/ml) were significantly higher than low-infection fish (142.0 mg/ml) and controls (159.5 mg/ml) after swim testing; levels increased significantly from resting values only in the moderate treatment. These results indicate osmoregulatory and cardiovascular stress occur in moderately infected fish during exercise. This lice-induced stress causes a decrease in swimming performance that compromises the overall fitness of Atlantic salmon.