Relative Weight as a Body Condition Index for Chain Pickerel

ABSTRACT

Weight-length data from 115 chain pickerel Esox niger populations from 13 states and one Canadian province were used to develop a standard weight (Ws) equation that would allow calculation of relative weight (Wr) values. We developed the 75th-percentile Ws equation using the regression-line-percentile (RLP) method. The proposed Ws equation is log₁₀ Ws(g) = −5.824 + 3.243 log₁₀total length (TL; mm). The English equivalent of this equation is log₁₀ Ws(lb) = −3.293 + 3.243 log₁₀TL(in). The equation is useful for 150 mm and longer chain pickerel. We found no evidence of consistent trends of increasing or decreasing _Wr values 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 further evaluation of _Wr as an index to growth and other physiological trends for chain pickerel.