Sciences de la volaille, de la pêche et de la faune
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Consequences of Anthropogenic Activities on Fish and the Aquatic Environment

Dawodu Bukola3*, Aderolu Zaid1, Elegbede Isa Olalekan2 and Adekunbi Falilu3

Persistence of pollution into our natural environment has concurrently led to instability, disorder, harm or discomfort to both the physical systems and living organisms inhabiting the ecosystem. Potentially harmful substances such as pesticides, heavy metals, paper mill waste, polychlorinated biphenyl and crude oil are often released into the aquatic environment. When large quantities of these pollutants are released there may be an acute impact as measured by large-scale sudden mortalities of aquatic organisms such as fish kills. Lower levels of discharge may result in an accumulation of the pollutants in body composition of fish. The effects of water pollution on fish species can be classified into acute effects and long term chronic effects, which includes immune-suppression, reduced metabolism, and damage to gills and epithelia. Pollution-related diseases include fin/tail rot, gill disease, hepatic damage and ulceration. Specific examples of fish diseases that reflect the effects of pollution include, fin and tail rot caused by Amnonas hydrophila and Pseudomonas jluorescens. The polluted water may have undesirable colour, odour, taste, turbidity, harmful chemical contents, toxic and heavy metals, pesticides, industrial waste products, domestic sewage, virus, bacteria, protozoa and worms. Fish species are not only tolerant to severe contaminated waters but show a variety of specific morphological deformities and lesions that appear to reflect the level of water pollution. Assessing morphological deformities is one of the most straightforward methods to study the effects of contamination on fish because of the ease of recognition and examination when compared with other types of biomarkers. The indiscriminate disposal of pollutants without pre-treatment should be discouraged. In order to avoid the effects of water pollution on fish health, effluents discharged from industries and other sources should be properly treated.