Chapter 5: Care, Handling, and Examination of Sampled Organisms
Cecil A. Jennings, Brian L. Sloss, Becky A. Lasee, Gary J. Burtle, and Gregory R. Moyer
Humans have used aquatic resources, especially fish, for food, raw materials for tools and ornaments, and recreation for millennia. In many cases, humans have caused declines in stocks of aquatic animals and have subsequently attempted to stabilize or reverse such declines. In most cases, the anthropogenic activity responsible for the decline cannot be remedied immediately, and conservation or mitigation actions are enacted (e.g., Ross 1997). However, in many instances the information (e.g., population rates, life history, and basic biology) necessary to devise meaningful and successful conservation or mitigation strategies is scarce or lacking, and obtaining it often requires capturing and handling organisms. For example, acquisition of data on movements, migration, population abundance, mortality, and behavior involves the capture, marking, and release of live fish that must survive and behave normally after release (Kelsch and Shields 1996; Chapters 11 and 18). In some cases, animals may need to be maintained in captivity for extended time periods. In others, examination of deceased specimens or tissue samples (e.g., blood or organs) may provide necessary information. Minimizing stress associated with the capture, handling, and holding of animals is necessary to reduce mortality and ensure that fish tolerate additional stressors (e.g., experimental procedures) that may be unavoidable (Kelsch and Shields 1996). In all cases, standard methods of handling, care, and examination provide for consistency of results, which leads to better inference about the populations under study and increased knowledge upon which mitigation measures or conservation efforts are based.
Proper care, handling, and examination of sampled organisms are central to all successful investigations, but traditionally what was considered “proper” varied among researchers and by research objectives. In time, standard protocols for these procedures were established, and the standards and the topics they address have evolved as our knowledge of organismal physiology, biology, and ecology has increased. The differences in the depth, breadth, and topical coverage between this chapter and its previous versions (Stickney 1983; Kelsch and Shields 1996) demonstrate this trend well. The diversity in the taxa and topics investigated by fisheries professionals requires a variety of sampling and examination protocols as well as institutional scrutiny to ensure that research organisms are treated in accordance with accepted protocols for animal care, handling, and examination. The information presented here is intended to acquaint the reader with standard and emerging protocols for examination and humane treatment of sampled organisms. This chapter is organized into sections on routine fish care and handling, fish health sampling, sonographic examination of fish, and curatorial methods.