Effects of Cadmium and Nickel on Embryonic Development of Fish: A Review

In fish embryos, a variety of abnormalities have been found, including stunted growth, a reduced survival rate, and aberrant development. One plausible explanation is that early embryonic stages are more sensitive. Embryonic studies provide additional information regarding the various impacts of heavy metals on fish, but information on larval abnormalities caused by waterborne metals is lacking. It is found that cadmium (Cd) causes a decrease in thyroid hormone levels as well as a disruption in fish growth hormone expression. Similarly, negative health effects have been documented as a result of nickel (Ni) exposure. Some toxic effects on organs, skin irritation, skin itches or blisters and allergic reactions may occur as a result of Ni exposure. This review study focuses on the impacts of Cd and Ni, on the embryonic development of different fish species. The evidence on abnormalities in fish larvae caused by Cd and Ni was also provided in text.