HOW DOES THE BODY-SCALE MODEL AFFECT BACK-CALCULATED GROWTH - THE EXAMPLE OF ARCTIC CHARR, SALVELINUS-ALPINUS (L), OF LAKE GENEVA (SWITZERLAND)

When back-calculating fish length from scale measurements, the choice of the body-scale relationship is a fundamental step. Using data from the arctic charr Salvelinus alpinus (L.) of Lake Geneva (Switzerland) we show the need for a curvilinear model, on both statistical and biological grounds. From several 2-parameters models, the log-linear relationship appears to provide the best fit. A 3-parameters, Bertalanffy model did not improve the fit. We show moreover that using the proportional model would lead to important misinterpretations of the data. © 1990 Birkhäuser Verlag.