Fish Necropsy

Fish are often used as sentinels of chemical contaminant exposure in the environment. Necropsy may be required to investigate fish kills or to establish ecological risks from sublethal levels of toxicant exposure by assessing aspects of their internal condition. This chapter illustrates techniques that may be used to perform fish necropsies in fish of the salmoniform and pleuronectiform body types. The techniques can be applied to fishes of different morphology, with only minor variations. One should characterize the epidermal integrity and condition of all fins. Record the location, size, and severity of ulcerations, abrasion, erosion, hemorrhage, other gross lesions, and parasitism. Extend all fins for proper inspection. Inspect the dorsal and ventral surface of the specimen. Distend the pelvic, pectoral and anal fins; record fin lengths and condition, and excise with scissors or scalpel if needed for study. One should also identify any ocular and dermal abnormalities and anomalies.