Abstract

<jats:p> We collected data on the most frequently encountered medium- to large-bodied littoral fishes in two independent sets of central Ontario lakes; the first set (10 lakes) was sampled between 1979 and 1980 and the second (15 lakes) from 1982 to 1988. Empirical models were constructed by correlating the strongest with in-year, among-lake trends in species abundance with the strongest among-lake trends in abiotic variables determined by principal coordinates analyses; indices of nearshore vegetation cover were also used as predictor variables. From 1982 to 1988, variation in abundance of Lepomis (pooled pumpkinseed (L. gibbosus) and bluegill (L. macrochirus)) was the major among-lake trend, and this was strongly correlated with differences in lake primary productivity (P &lt; 0.02 for each year) and nearshore macrophyte cover (P &lt; 0.03 for each year). In 1979–80, variation in abundance of pumpkinseed was the major among-lake trend, and this was strongly correlated with among-lake variability in nearshore macrophyte cover (P = 0.006) and lake flushing rate (P = 0,008); bluegill were not present in these lakes. Among-lake variation in food availability and/or abundance of refuges from predators may be factors responsible for the among-lake patterns in Lepomis abundance. </jats:p>