Among-Population Variability of Fish Growth: I. Influence of the Quantity of Food Consumed

Abstract

We assessed the relationship between in situ fish growth and food consumption for a series of yellow perch (Perca flavescens) populations that exhibited a 1.8 to 10-fold range in growth rates on a weight basis. Perch from 12 populations (lakes) and three year–classes (I +, II +, and III +) were sampled at 3–4 wk intervals from late May to late September 1985. On each occasion, water temperature profile and daily ration were determined. Among-lake water temperature differences were minimal (of the 12 lakes studied 10 had mean water temperatures of 19.0 ± 1 °C) and could not explain growth differences. Food consumption covered a four-fold range within each age–class and varied significantly among populations but not among age–classes. Food consumption explained a significant proportion of among-population variability in perch growth rates only for age I + fish (r2 = 0.52). We argue that other factors such as prey type, prey availability, and fish community descriptors are important determinants of among-population growth variability in the lakes we studied, and by implication, in other systems.