Abstract

One of the most challenging and potentially dangerous of all marine stranding response actions is the safe and humane euthanasia of cetaceans. Our experiences and those of colleagues in the Marine Mammal Stranding Network, as well as the sparse information and guidance available, inspired a 2 year collaborative John H. Prescott grant project to develop recommendations for euthanasia of stranded cetaceans when release or rehabilitation is not an option. Towards that end, we developed standardized methods of data collection for cetacean euthanasia events, collected pertinent historic data from stranding networks nationwide, and compiled a review of grey and peer-reviewed euthanasia literature. To ensure critical issues were addressed, we developed and administered a cetacean euthanasia questionnaire to stranding organizations nationwide. We convened a working group of experienced veterinarians, marine biologists and stranding response personnel to review this information and develop recommendations. The final report includes recommendations for euthanasia of stranded cetaceans, option matrices for large and small cetaceans, a summary of effective euthanasia methods, species specific length-weight equations and graphs to facilitate dose calculations in the field, species specific observations, routes and methods of administration, aggregate historic drug dosages for commonly encountered species, illustrations for routes of administration and adjunct physical methods, and a standardized euthanasia record form.¹ A stand-alone document, "Recommendations for Euthanasia of Stranded Cetaceans," is being distributed to participating organizations in the Marine Mammal Stranding Network.²

Of the 468 records reviewed, 300 provided adequate information for demographic analysis of cetacean strandings resulting in euthanasia. Over 90% occurred in the southeast and northeast regions of the U.S. There were more mass stranding euthanasias in the northeast and more single stranding euthanasias in the southeast, but nearly twice as many single stranding euthanasia events overall. Of the total records collected nationwide, 283 (60%) representing 20 species met project inclusion criteria regarding euthanasia methods, drugs and dosages. Chemical administration represented the most common practice during a euthanasia event (281 of 283). Injection with sodium pentobarbital alone represented 166 (59%) of the 281 cetacean euthanasias, while premedication followed by sodium pentobarbital accounted for 26% (N = 72). The number of premedication agents administered preceding sodium pentobarbital varied from one to three: one agent (N = 45); two agents (N = 23); and three agents (N = 4). The most common single premedication agents included diazepam (N = 19) and xylazine (N = 12). The most frequently administered two-agent premedication included acepromazine/xylazine (N = 7) and diazepam/xylazine (N = 7) combinations. Forty-two chemical euthanasia events (15%) did not include the administration of sodium pentobarbital. Of these, single agent chemical euthanasias accounted for 10 events. These single agent events usually occurred because the animal expired prior to further agent administration, rather than as an intended euthanasia protocol. In 28 (67%) of the 42 events in which sodium pentobarbital was not administered, two agents were used. The most common combination consisted of acepromazine and xylazine (N = 23). Protocols and dosages varied widely based on numerous factors, but aggregate data provided a good starting point to combine with experiences of working group members to propose effective euthanasia protocols for stranded cetaceans when necessary.

Acknowledgements

Bill Van Bonn, Christopher Dold, Kimberly Durham, William McLellan, Connie Merigo, Katie Moore, Michael Moore, Megan Stolen, Michael Walsh, Teri Rowles, Sentiel (Butch) Rommel, Gretchen Lovewell, Claire Hohenwater, Brandy Velten, D. Ann Pabst, Heather Beveridge, Rogers Williams, Tim Tristan, Michele Barbieri, Yara Bernaldo, Kathy O'Hara, Christina Trapani, and Jackie Bort all made significant contributions to the project. Data contributors included Allied Whale, Center for Marine Sciences and Technology, Georgia Department of Natural Resources, Hubbs-SeaWorld Research Institute, International Fund for Animal Welfare/Cape Cod Stranding network, Mystic Aquarium, National Aquarium in Baltimore, New England Aquarium, NOAA NOS Charleston Laboratory, Cape Hatteras National Seashore (NPS), North Carolina Division of Marine Fisheries, NC Wildlife Resources Commission, Oregon Marine Mammal Stranding Network, Riverhead Foundation for Marine Research and Preservation, SeaWorld of Orlando, Texas Sealife Center, The Marine Mammal Center, University of New England Marine Animal Rescue Center, UNC Wilmington, Virginia Aquarium & Marine Science Center, and Washington Department of Fish and Wildlife.

* Presenting author

Literature Cited

1.  Barco SG, Walton WJ, Harms CA, George RH, D'Eri LR, Swingle WM. 2012. Collaborative development of recommendations for euthanasia of stranded cetaceans. Final report to NOAA/NMFS for John H. Prescott Award #NA09NMF4390212. VAQF Scientific Report 2012–06. Virginia Beach, VA. 183 p.

2.  Barco S, Walton W, Harms C, George R, D'Eri L, Swingle W, Barbieri M, Beveridge H, Dold C, Durham K, McLellan W, Merigo C, Moore K, Moore M, Rowles T, Stolen M, Van Bonn W, Walsh M. 2012. Appendix 2: Recommendations for euthanasia of stranded cetaceans. From the final report to NOAA/NMFS for John H. Prescott Award #NA09NMF4390212. VAQF Scientific Report 2012–06. Virginia Beach, VA. 27 p.