Marine mammal entanglement in fishing gear is a global problem that impacts more than 260 species including marine mammals, sea turtles and seabirds. The immediate effects of entanglement include mortality, serious injury, minor injury, or no injury. Long-term effects include deteriorating health, decreased reproductive ability, or no impact. The deleterious effects of entanglement occur most frequently at the level of the individual.^1,2 More whales, dolphins and porpoises die every year by getting entangled in fishing gear than from any other threat. Small whales, dolphins and porpoises are most vulnerable because they generally aren't strong enough to break free from nets and come to the surface to breathe. For these smaller cetaceans, entanglement can cause death by drowning.³ Effects of fishing gear interactions are among the most pressing issues currently being addressed by marine mammal management agencies in the United States. While the entire emphasis of management agencies has been on commercial fisheries; little notice has been taken of the impacts of recreational fisheries.² In the Southeastern United States (SEUS) region, between (2003–2010) there were a total of (33) marine mammal entanglements involving Atlantic bottlenose dolphins (Tursiops truncatus) that were identified by the National Marine Fisheries Service (NMFS) as having life threatening entanglements from commercial, recreational fishing gear, and other marine debris.⁴ In such cases where life-threatening anthropogenic stressors are identified, efforts to intervene are made by NMFS. In such instances, NMFS Regional Stranding Coordinators develop a response effort and resources that involve members of the Marine Mammal Health and Stranding Response Network, assigned capture specialists, and marine mammal veterinarians. These field operations are logistically complex, requiring 4–6 small (chase) boats, specialized capture equipment, medical supplies, telemetry systems and a team of 20–40 individuals possessing a broad range of capabilities. The goal of intervention operations is to safely capture, conduct physical examinations, collect samples, mark and release the target animal as quickly and safely as possible with a minimum of stress to personnel and to the dolphin. In some instances, post-release monitoring is desirable to document wound healing rate, body condition, movement and overall longevity. This presentation highlights and provides examples from eight interventions that occurred in Florida, Texas and Georgia from 2003 to 2010. These examples demonstrate the challenges of planning and conducting open-water capture and treatments, as well as the benefits of collaborating with various individuals, organizations and agencies.

Acknowledgements

The authors wish to thank members of SEUS NOAA Fisheries Marine Mammal Health and Stranding Response Network and SEUS Regional Stranding Coordinators Blair Mase Liz Touy Sheen and NOAA Fisheries Regional Managers, including Erin Fourges. The authors also wish to acknowledge additional support provided by a number of organizations and individuals including the Texas Marine Mammal Stranding Network, National Ocean Services, Georgia Aquarium, Dolphins Plus, Marine Mammal Conservancy, Wildlife International Network, Ocean Embassy, University of Florida, Hubbs-SeaWorld Research Institute, Volusia County, Florida Fish and Wildlife Conservation Commission, Sea Turtle Conservation of Texas, Clearwater Marine Aquarium, Georgia Department of Natural Resources, Skidaway Institute of Oceanography, Dr. Tim Tristen, Dr. Bob Stevens, Dr. Michael Walsh, Dr. Forrest Townsend, Dr. Kattis Stengard, Dr. Janet Whaley and Dr. Gregory Bossart. The authors also wish to acknowledge our mentor, friend and fellow colleague Dr. Deke Busse, who continues to inspire and guide us.

References

1.  Asmutis R. 2004. Gerry E. Studds Stellwagen Bank National Marine Sanctuary Marine Mammal Entanglement Working Group Action Plan.

2.  Wells RS, Hoffman S, Moors TL. Entanglement and Mortality of bottlenose dolphins (Tursiops truncatus) in recreational fishing gear in Florida. Fishery Bulletin 1998; 96: 647–650.

3.  Cetacean Bycatch Resource Center http://www.cetaceanbycatch.org/species_risk.cfm

4.  NOAA Fisheries http://www.alaskafisheries.noaa.gov/protectedresources/entanglement