Tooba Andalibi - Department of Environmental Sciences, Environmental University
Behzad Saeid Pour - Department of Environmental Sciences, Environmental University
Seyyed Mahdi Mirashrafi Langroudi - Department of Fisheries, Faculty of Natural Resources, University of Zabol

Biological characteristics of species with limited geographical distribution, is veryimportant. One of the main biological features is growth. Hence, this study was aimedto investigate the growth pattern of stream Loach fish (O. tongiorgii) duringNovember 2013 with collecting 140 Loach fish captured by a surber-type fishsampler from the Rudbal River. The mean total length and weight were 4.70 ± 0.39cm and 0.84 ±0.21 g, rand the minimum and maximum total length and total weightwere 4.00-4.00 cm and 0.487-1.762 g, respectively. Length-weight relationships wasestimated as W = 0.0182TL 2.453 for males, W = 0.0087TL 2.899 for females, and W =0.0135TL 2.697total fish. The correlation value was more than 80% and significantregression equation was observed. The results showed negative allometric growthpattern. The condition factor in males and females, was 0.79 ± 0.05 and 0.74 ± 0.05,respectively, with a total CF of 0.77 ± 0.06.

The pattern of growth, O. tongiorgii, basic river Rudbal, Iran