The involvement of pollution with fish health

It is generally accepted that pollutants, such as hydrocarbons, enter the aquatic environment by accident or deliberately, and may lead to large-scale and sudden kills of animal life, especially when the compounds are in high quantities. However, more subtle changes to the host may ensue when lesser quantities of pollutants are involved. Here, the resulting damage may include immunosuppression, physical damage to gills and epithelia, and adverse affects on metabolism. Also, there may well be increased susceptibility to various infectious diseases, including lymphocystis and ulceration. Much of the work to date has centered on laboratory studies and also surveys of polluted and clean marine sites, but it is not always possible to make firm conclusions from the data