Comparison of growth performance and morphological variation among three carp species (Cyprinus carpio, Hypophthalmichthys molitrix, and Labeo rohita)

Abstract

This study was designed to analyse the water quality parameters and external morphological characters of three selected carp fish species i.e.,Cyprinus carpio, Labeo rohita,andHypothalamus molitrixfrom the Hub Dam of District Lasbela, Baluchistan. About Sixty specimens were collected for each carp fish species from April 2019 to March 2020, and their morphological characters were measured. The overall study of water quality parameters of Hub dam was found in the optimal range. The results of the Cube law revealed that the regression coefficientb-value was<3.0, which means that these species show positive allometric growth patterns that are, b = 2.07 forC. carpio,b = 2.04 forH. molitrix, andb = 0.12 forL. rohita.Moreover, the Correlation value‘r’between length and weight data forC. carpioandH. molitrixwas found moderate and significant (r > 0.60; p < 0.05), while weak (r < 0.50; p < 0.05) and insignificant inL. rohita, respectively. The mean values of condition (K) and relative condition factors (Kn) were 1.0 which shows a good condition in Hub dam for fish growth. The overall results of linear relationships between 18 morphometric charactersvswhole body growth (TL) revealed that a strong correlation (r > 0.70) was observed among TLvsFL and TLvsLD and moderate (r > 0.60; p < 0.05) and negative correlation also seen in between TLvsBDL and in most meristic characters ofC. carpio.Likewise, mostly moderate (r > 0.60) and weak (r < 0.50) types of correlation were seen in most morphometric and meristic characters ofH. molitrixandL. rohita, except few meristic characters ofL. rohitashow negative type relation with body growth (TL). This study was the first approach to examine the growth patterns of different carp species of Hub dam and observe their morphological variations among these carp species that have great potential value in systematics and fisheries management.