Impacts of Water Pollution on the Fecundity and Reproductive Physiology of Selected Freshwater Fishes in the Godavari River: A Systematic Review

Abstract

The Godavari River is one of the most important freshwater ecosystems in peninsular India, supporting aquatic biodiversity, agricultural production, and inland fisheries. Increasing urbanization, industrial discharge, domestic sewage, agricultural runoff, and plastic contamination have raised concerns regarding the ecological condition of the river and the reproductive health of its fish populations. This review examines the relationship between water pollution and fish fecundity, with particular reference to Labeo calbasu, Cirrhinus mrigala and Mystus seenghala. Relevant evidence concerning river water quality, potentially toxic elements, microplastics, and pollutant-induced reproductive dysfunction is synthesized to identify plausible mechanisms and important research gaps. Reproductive endpoints considered include absolute and relative fecundity, gonadosomatic index (GSI), gonadal maturation, oocyte atresia, vitellogenin responses, oxidative stress, and egg viability. Published investigations have documented potentially toxic elements and microplastics in the Godavari system, while experimental studies in freshwater fishes demonstrate that certain contaminants can interfere with endocrine regulation and ovarian development. However, evidence directly linking measured pollution exposure to reduced fecundity in each of the five focal species within the Godavari remains limited. The available literature therefore supports concern about reproductive risk but does not establish a uniform, basin-wide decline in fish fecundity. Integrated monitoring of water, sediment, fish tissues, and reproductive biomarkers is needed to determine the extent of these effects and inform fisheries conservation.