Movements and Behavior of Smallmouth Bass, Micropterus dolomieui, and Rock Bass, Ambloplites rupestris : in Southcentral Lake Ontario and Two Tributaries

Abstract

Movements and behavior of potamodromous smallmouth and rock bass in Lake Ontario were examined in the spring and summer 1985- 86 . Bass were captured by electrofishing near spawning areas in two tributaries 60 km apart . Fitted with temperature-sensing radiotransmitters, bass were released near capture sites or displaced to Lake Ontario 3-10 km from their "home " tributaries. Twenty six and 42 % of displaced smallmouth and rock bass returned to original capture sites in tributaries. Non-homing fish generally dispersed along the lake shore and frequently established home ranges 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 there were differences between lake and creek habitats and species. 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 20-22 degrees Celsius temperatures in lake and tributary habitats when available. Smallmouth bass were most active in May, least active in July, and more active in the lake than in tributaries. Rock bass activity did not appear to vary by season or habitat. Bass activity in Lake Ontario was positively correlated with diel illumination.