RELATIVE WEIGHT AS A BODY CONDITION INDEX FOR CHAIN PICKEREL

Weight-length data from 115 chain pickerel Esox niger populations from 13 states and one Canadian province were used to develop a standard w eight (Ws) equation that would allow calculation of relative weight (W r) values. We developed the 75th-percentile Ws equation using the regr ession-line-percentile (RLP) method. The proposed Ws equation is log(1 0)Ws(g) = -5.824 + 3.243 log,,total length (TL; mm). The English equiv alent of this equation is log(10)Ws(lb) = -3.293 + 3.243 log(10)TL(in) . The equation is useful for 150 mm and longer chain pickerel. We foun d no evidence of consistent trends of increasing or decreasing Wr valu es calculated with the proposed RLP Ws equation. We recommend the use of the proposed RLP Ws equation for assessment of chain pickerel body condition. The proposed Ws equation should serve as a basis for furthe r evaluation of Wr as an index to growth and other physiological trend s for chain pickerel.