Dispersion of Rock Bass along the South Shore of Lake Ontario

Abstract

Abstract From 1972 through 1981, 7,008 rock bass Ambloplites rupestris were tagged at sites along the southern shore of Lake Ontario; 854 tags (12.2%) were returned by anglers or recovered in the tagging program. Mean time and distance between tagging and recapture were 238 days and 15.5 km. Mean distance between release and recapture sites increased with time. One fish was taken 241 km from the release point. Rock bass tagged and recaptured in the prespawning period dispersed further than those tagged and recaptured after spawning. The predominantly eastward current along the southern shore of Lake Ontario had little overall effect on rock bass movements, but localized current patterns were reflected in dispersal. When dispersal from sites influenced by a thermal power-plant discharge was compared to that from control sites, slightly more rock bass stayed in warmer plume areas than in nonplume areas, although few remained long in any one location. As has been found with other animal species, dispersal of...