Movements and Behavior of Smallmouth Bass, Micopterus dolomieul, and Rock Bass, Ambloplites rupestris, in Southcentral Lake Ontario and Two Tributaries

Abstract

movements and behavior of 56 stream-spawning smallmouth bass and rock bass from Lake Ontario were examined in spring and summer 1985 and 1986. Fish were captured by electrofishing near spawning areas in two tributaries 60 km apart, fitted with temperature-sensing radiotransmitters and released in their "home" tributaries or or displaced to the lake 3 - 10 km from those tributaries. twenty-six percent of displaces smallmouth bass and 42% of rock bass returned to their original sites of capture in tributaries. Non-homing fish generally dispersed along the lake shore and eventually established small residence areas in the lake, often near home or other tributaries. No differences were observed in movement rates, temperatures occupied or diel activity patterns between years or tributary stocks, but differences were found between species and between lake and tributary habitats for smallmouth bass. Smallmouth bass homing to, or released in, tributaries generally established home ranges downstream from spawning areas and often occupied tributaries all summer, but rock bass did not. Both species occupied temperatures between 20-22 C in lake and tributary habitats when available. Smallmouth bass were most active in May, least active in July and generally more active in the lake than in tributaries. Rock bass activity did not appear to vary by season or habitat. Both specie were most active in Lake Ontario in mid-day; differences in tributaries were less pronounced.