Development of Condition and Length-Categorization Standards for Saugeye

Abstract

ABSTRACT Weight-length data for 32 (N=3,371) saugeye (walleye Stizostedion vitreum x sauger Stizostedion canadense hybrids) populations from eight states were used to develop a standard weight (Ws) equation. We used the regression-line-percentile technique, which provides a 75th-percentile standard, to develop the equation. The proposed Ws equation is log10 Ws(g) = −5.692 + 3.266 log10TL(mm), and the English equivalent is log10 Ws(lb) = −3.760 + 3.266 log10TL(in). The saugeye Ws equation is valid for fish ≥ 170 mm. The proposed Ws equation was used to calculate relative weight (Wr) values for individual fish from each population to test for length-related biases. A significant relationship between total length and Wr was observed in 18 of the 32 populations. Ten populations had negative slopes while eight had positive slopes. There was no significant difference in the occurrence of positive and negative slopes (X 2=0.22, P≥0.50); therefore, no length-related biases were evident for the populations used in...