For toxicology and carcinogenicity research, protocols must be developed to deal with the discharge water depending on the toxicant used. This is less of a problem if the toxicant is administered by another route (such as orally or by gavage or injection). For other types of research, the protocols will vary greatly depending on the species and experimental design. For example, in vitro studies using fish tissues mostly require maintenance and sacrifice of the experimental fish. On the other hand, studies measuring physiological
parameters may require surgical manipulations or catheterizations. Such procedures must be developed on a case-by-case basis.