Sg. Hinch et Nc. Collins, RELATIONSHIPS OF LITTORAL FISH ABUNDANCE TO WATER CHEMISTRY AND MACROPHYTE VARIABLES IN CENTRAL ONTARIO LAKES, Canadian journal of fisheries and aquatic sciences, 50(9), 1993, pp. 1870-1878
We collected data on the most frequently encountered medium- to large-
bodied littoral fishes in two independent sets of central Ontario lake
s; 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 within-year, among-lake trends in specie
s abundance with the strongest among-lake trends in abiotic variables
determined by principal coordinates analyses; indices of nearshore veg
etation 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 thi
s was strongly correlated with differences in lake primary productivit
y (P < 0.02 for each year) and nearshore macrophyte cover (P < 0.03 fo
r each year). In 1979-80, variation in abundance of pumpkinseed was th
e major among-lake trend, and this was strongly correlated with among-
lake variability in nearshore macrophyte cover (P = 0.006) and lake fl
ushing rate (P = 0.008); bluegill were not present in these lakes. Amo
ng-lake variation in food availability and/or abundance of refuges fro
m predators may be factors responsible for the among-lake patterns in
Lepomis abundance.