Spline Interpolations besides Widely Used Growth Models for the Fork Length of Flathead Trout Called Salmo Platycephalus Population from Zamanti Stream of Seyhan River in Turkey

Abstract

In this study, the fork length growth of the flathead trout (Salmo platycephalus) found in Zamanti Stream of Seyhan River were investigated. For this purpose,  for growth curve, spline interpolation functions, alternative modeling passing to exactly all data points with respect to widely used models such as von Bertalanffy, logistic and Gompertz models, applied to growth data set were used. These interpolation functions and growth models used were examined separately for female, male and combined sex. These interpolation models used are linear spline, quadratic spline and cubic spline functions. The fork length curves of these spline interpolation functions and growth models were shown on the same graph. Thus, the differences in these models have been observed. It could be say that different spline interpolation functions especially cubic spline interpolation functions, used for each consecutive two data points, compared with other classical models have the best fit according to the criteria of the error sum of squares (SSE). The estimates for some intermediate values were done by using these spline interpolations and growth models.

Keywords: Spline Interpolations, Growth models.