Evaluation of total-body electrical conductivity to estimate whole-body water content of yellow perch, Perca flavescens, and alewife, Alosa pseudoharengus

We evaluated the use of total body electrical conductivity (TOBEC) for dete rmination of whole-body water content of yellow perch, Perca flavescens, an d alewife, Alosa pseudoharengus. We used multiple linear regression with ba ckwards stepwise elimination to test the capability of TOBEC values, wet we ight, and total length in predicting whole-body water content of yellow per ch and alewife. We found that wet weight was the best predictor of whole-bo dy water content. The inclusion of TOBEC values in multiple linear regressi ons did not improve the predictive capability of wet weight over simple lin ear regressions that used wet weight alone (r(2) increased by only 0.00002 to 0.0005). We reanalyzed the data from three previous studies that used TO BEC to evaluate the tissue composition of fish. Again we found that the inc lusion of TOBEC values in regression functions with wet weight as the other independent variable did not substantially improve the predictive capabili ty of functions that used wet weight alone (r(2) increased by only 0.00003 to 0.0007).