Marine Mammal Analgesia: Where Have We Been and Where Do We Still Need to Go?
1Vancouver Aquarium, Vancouver, BC, Canada; 2SeaWorld Parks & Entertainment, Orlando, FL, USA; 3The Marine Mammal Center, Sausalito, CA, USA; 4Animal Welfare Department, University of British Columbia, Vancouver, BC, Canada
There is an increasing effort to understand, evaluate, and minimize pain in marine mammals. Pinnipeds, otters, and cetaceans admitted to rehabilitation centers often present with traumatic injuries or other presumably painful conditions. Recent advances in anesthetic drugs, patient monitoring, and our understanding of marine mammal physiology have resulted in increased numbers of surgical procedures on marine mammals maintained in zoos and oceanaria. Nutrition and husbandry continue to improve and many marine mammal species are living long enough to develop typically painful geriatric diseases such as non-infectious arthritis, neoplasia and periodontal disease. Lastly, wildlife biologists whose research may involve potentially painful procedures be performed on free-ranging animals are increasingly working with veterinarians to minimize animal discomfort and provide appropriate analgesia. As professional advocates for and effectors of animal health and welfare, marine mammal clinicians are continually challenged to address analgesia in animals under our care.
However, our understanding of how best to assess pain and provide analgesia remains very limited, particularly in marine mammals. Analgesics are often chosen based on empirical data from other species and individual clinical experience. There are few pharmacokinetic trials and even fewer studies that actually evaluate efficacy of various analgesics in different marine mammal species. There are potentially very serious side-effects of many analgesic agents and more research on effective dosages, dosing schedules, and routes of administration is desperately needed. Below is a list of some analgesic agents that have been used in marine mammals.
Sincere thanks go to Drs. Eric Jensen of the U.S. Navy Marine Mammal Program and Jenny Meegan of the National Marine Mammal Foundation for their insight, input, and comments.
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