Morphometric studies of cold water fish rainbow trout oncorhynchus mykiss in relation to body size

Eighty four farmed Rainbow trout, Oncorhynchus mykiss of different body sizes ranging from 4.8 to 38.5 cm in total length and 1.11 to 725g in body weight were used for the analysis of morphometric variables of head length (HL), head width (HW), pectoral fin length (PFL), dorsal fin length (DFL), body depth (BD), body girth (BG), tail length (TI.L) tail width (TI.W) in relation to total length (TL) and wet body weight (W) of the fish to investigate allometric growth was observed that all these relationships had very significant correlation. Slopes of the log transformed data were used to compare with an isometric slope (b = 1 or b = 0.33 or b = 3.0). All the parameters examined showed isometric growth in relation to either total length or body weight. Growth in weight was almost proportional to the cube of its length. Values of the slope (b = 3.12) coincide with the slope of an ideal fish. Regression parameters were found to be highly significant.