Effect of heavy metals in fish reproduction: A review

Heavy metals are ubiquitous and deleterious contaminant present in the aquatic ecosystem. Their concentration has increased magnificently due to anthropogenic wastes, geochemical composition, farming and mining activities. Fishes are susceptible to heavy metal contamination and fishes live in aquatic environment which made them inevitable exposure to heavy metal. The excess release of contaminants into aquatic ecosystem has forced the fish to accumulate more heavy metal in their tissues. However, fishes reproduce in natural ecosystem which might have contaminated with heavy metal. Fish reproduction is the key process for fish recruitment in natural ecosystem and inevitable for aquaculture production. Water quality in terms of heavy metal contamination has a definite impact on fish reproduction. Hence, it is important to know the consequence of heavy metals on aquatic ecosystem and their effect on fish reproduction. Several reviews and reports are available that deals with the effect of heavy metals on fish health, blood biochemical changes and histological changes, cellular and physiological stress in vital organs but few comprehensive reports on toxic effect of heavy metals on fish reproduction are available. Heavy metals are reported to cause reproductive disruption in fish, inhibiting induction of vitellogenin, delaying oogenesis, enhancing luteinizing hormone secretion, declining parameters of gonadal somatic index and ovulation in fish. Therefore, this review paper presents a holistic details on the toxic effects of heavy metal on fish reproduction with special reference to male and female reproductive system.