Determinants of growth and body condition of lake sturgeon (Acipenser fulvescens)

Determinants of variations in growth in length and body condition of lake sturgeon (Acipenser fulvescens) were studied on 32 lake and river systems covering most of the distribution of the species. The average of mean total lengths at ages 23-27 years and the weight of a 1000-mm specimen were chosen as growth and condition indicators. A latitudinal gradient in temperature, pH, and conductivity characterizes the eastern part of the distribution (less than or equal to 80 degrees W) whereas the western part (>80 degrees W) shows essentially the same temperature gradient but relatively high and stable pH and conductivity values from south to north. Growth decreases with mean annual air temperature and latitude in both sectors, but it is generally faster in the west than in the east. Although mean annual air temperature was the best individual predictor of growth (R(2) = 0.53), a multivariate model incorporating latitude and longitude explained a higher proportion of the variation in the dependent variable (R(2) = 0.67). Condition decreases with latitude in the east but remains relatively stable in the west. pH was the best individual predictor of condition (R(2) = 0.43).