Effects of Climatic Changes on Fish Diversity and Abundance and Prevalence of Fish Parasitic Infections in Southern Nigeria

Abstract

An important component of the natural resources in Nigeria is fishery and aquaculture. These resources are vulnerable to climatic change with a consequential effect on the socio-economic life of the people. The major contributory factor to climate change in Nigeria is the release of harmful substances into water bodies and the atmosphere from oil and gas extracting sector, including gas flaring in the Niger Delta. Climate change especially due to global and ocean warming lead to sea level rise and floods. Associated with these effects of climate change are outbreak of food and water-borne infectious diseases and agents, emergence of new diseases, resurgence of old diseases and redistribution of vector borne diseases. Studies carried out at Ikpoba River, Benin City, Nigeria, showed a great reduction in the diversity of fish over the years (58 species in 1988, 39 in 2004 and 7 in 2012). A high prevalence of parasitic infections was observed in the studies (22.9% and 15.6%). Some of the parasites recorded in 2004 were absent in 2012. The observed reduction in fish diversity is associated with climate change causing alteration in fish metabolism and physiology with consequences for growth, fecundity, feeding, behaviour, distribution and migration. High prevalence of parasitic infections observed in the studies could be a consequence of increased transmission rates of parasites with increasing temperatures due to global warming. Reduction in fish species over the years was accompanied by reduction in parasite species. Effects of climate change working synergistically with effects from anthropogenic stressors such as contaminants from oil spills and effluents, undoubtedly, have adverse effect on fish population and their parasites.
Keywords: Climatic changes, Fish, Diversity, Prevalence, Parasitic infections