Heavy metal contamination in freshwater habitats impairs the growth and reproductive health of wild spotted snakehead Channa punctata (Channidae) in Bangladesh

Heavy metal bioaccumulation in aquatic organisms of open water aquatic ecosystems was detected globally, including Bangladesh. This study evaluated the hypothesis of whether heavy metal contamination in aquatic habitats impacts fish growth and reproduction using wild <i>Channa punctata</i> as an experimental animal. The growth and reproductive health of a wild freshwater fish, <i>C. punctata</i>, collected from five freshwater habitats, were assayed with heavy metal bioaccumulation. Atomic absorption spectrometry detected the bioaccumulation of cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb) in the muscle of <i>C. punctata</i>. Cd, Cr, and Pb concentrations were the highest in the specimen collected from the Turag River and the lowest in the Dharla River. The highest concentration of Hg was found in <i>C. punctata</i> specimens collected from the Karatoya River (0.093 ± 0.004 mg/kg). The length-weight relationship and condition factor of <i>C. punctata</i> indicated a negative allometric growth pattern (<i>b</i> < 3.0) and poor wellness (F < 1.0) in all the stocks except Dharla River. We estimated the size at first sexual maturity (L50), ova diameter, fecundity, and gonadosomatic index (GSI) to assess reproductive health and determined the correlation with heavy metal bioaccumulation. We found that higher bioaccumulation of heavy metal impairs the reproductive health of <i>C. punctata</i> by lowering spawning performance. This study showed that heavy metal bioaccumulation impaired fish's growth and reproductive health, potentially affecting future recruitment and fishery sustainability.