地理ジャーナルと自然災害
オープンアクセス

概要

Maturation and Reproductive Biology of Reba Carp Cirrhinus Reba (Hamilton) in Lower Anicut Reservoir, Tamil Nadu, India

Mathialagan Ramasamy and Sivakumar Rajangam*

Examine the reproductive biology of Cirrhinus reba at Lower Anicut reservoir and analyses of gonads assessed by ovarian cycles. Sex ratio, size at first maturity, GSI, macroscopic appearance ovary, fecundity, oocyte diameter and histological examination suggested as a result of spawning season. Males were 59.4% and females 40.6% suggested the ratio significantly deviated from expected 1:1. Size at 50% maturity estimated from logistic model curve 132 mm in males and 148 mm for females. GSI was represented increasing the development of gonads in both sexes until it was ripe and spent. During spawning, increasing the length and weight of gonads from immature to ripe, maximum values of GSI for both sexes (3.43%-3.49% to 4.09%- 6.01%) were obtained during April to August with peak in July. Size-frequency distribution of ova diameter were clearly indicate maximum values of diameter enclosed during July to corresponding microscopic stages of gonads. Five stages of oocyte development were determined through histological examination can be divided immature, maturing, matured, ripe and spent. Total length, weight, gonad length and weight were significantly related to fecundity. Stocks of C. reba were enclosing females spawn once a year during spawning season. Following, the implications for management and controlled feral carp stocks were discussed in detail.