Whats old is new again (New World screwworm, that is)
In talking to people about what our agency does for endangered species, you can’t help but conjure up images of those iconic species that have helped frame the visual; species like sea turtles, manatees, wood storks, red-cockaded woodpeckers, whooping cranes, and freshwater mussels. The Southeast Region is the lead for about 380 endangered species of plants and, animals and among those Southeast, we get to claim is Florida’s endangered Key deer.
Standing only about three feet tall, this smallest subspecies of the North American white-tailed deer is unique to about 20 to 25 of the Lower Florida Keys islands. Geographically and genetically isolated from other populations of white-tailed deer, they have evolved and adapted to the environment of the Keys. Years of over-hunting, habitat degradation, fragmentation, and human disturbance drove this species to the brink of extinction by the early 1950s, reducing the herd to only a couple dozen individuals.
With the passage of the Endangered Species Preservation Act of 1966, Congress enacted the very first piece of comprehensive endangered species legislation. It was under this act that the first list of threatened and endangered species was compiled – to include Florida’s Key deer - officially listed as federally endangered on March 11, 1967. Although population gains have been made over the years, Key deer remain under threat of extinction and continue to be listed as endangered.
Created for the purpose of protecting and maintaining the remaining habitat for the Key deer and actively managing the population, the National Key Deer Refuge was established in 1957. In 1968, the Service bought the first habitat for protecting an endangered species – purchasing 2,300 acres for the Florida Key deer. Today, the refuge consists of more than 84,000 acres in the Lower Keys (8,983 are terrestrial), a patchwork of small and large tracts of pine rockland, mangrove forest, hardwood hammocks, freshwater wetlands, and marine waters.
A horror began to unfold for this species in July of 2016. Sick deer were being reported with increased frequency to refuge staff - and these deer were more than just “sick”. They were showing up with large, maggot-infested wounds – wounds unlike refuge staff had ever seen before. Specimens of the fly larvae collected from the deer were submitted to the University of Florida and the United States Department of Agriculture’s (USDA) National Veterinary Services Laboratories in late September and both entities quickly confirmed these larvae as New World screwworms.
New World screwworms are fly larvae that can infest livestock and other warm-blooded animals, including people. Most often entering an animal through an open wound, they feed on the animal’s living flesh. If not treated, infestations can be fatal. By early October, more than 100 Key deer had either been killed by New World screwworms or had to be euthanized. A crisis had erupted for this imperiled population of Key deer and it became an “all-hands-on-deck” undertaking at the Florida Keys National Wildlife Refuges Complex.
On October 3, 2016, a unified Incident Command Post was established to address the eradication of New World screwworms, protect human health, Florida’s livestock industry, and other animals. Personnel from multiple regions and programs (Refuges, Ecological Services, Fire, and Law Enforcement) were down to south Florida to work with USDA, Florida Department of Agriculture and Consumer Services, and other partnering agencies under this unified command. More than 125 interagency responders answered the call to unite and address the emerging New World screwworm infestation in south Florida. By mid-October, the Service had established an Incident Management Team, located at the Refuge Complex Administrative Headquarters on Big Pine Key, to focus efforts on prevention of extinction and recovery of the Key deer.
Through the Incident Management Team, Service biologists and wildlife veterinarians have been working countless hours, devising techniques for treating infestations in Key deer and administering preventative medications. Remote medication stations, designed and constructed by refuge staff and others detailed to the incident are helping to treat deer in remote locations. Refuge staff also has been coordinating volunteer efforts for aiding in the administration of anti-parasitic medications to the more urban deer population - a true village undertaking!
Service biologists also are working closely with researchers at Texas A&M to monitor and track the Key deer population. To date, 135 Key deer have been lost due to New World screwworm. Prior to New World screwworm, population estimates ranged from 800-1,000 Key deer. A population study concluded by Texas A&M in November 2016 places that number now somewhere around 875. Those same researchers are working with the Service on an effort to trap and radio-collar 30 adult/yearling female Key deer to assist with gathering weekly population estimates, monitoring of females during the fawning season, and if needed, facilitating preventative treatments.
Joining forces with the USDA, the Service and other agencies have been assisting with addressing eradication of New World screwworm with a form of biological control called the sterile insect technique. The technique involves releasing male flies in infested areas; when those sterile males mate with local females, no offspring result. This recent outbreak is the first local detection of New World screwworm in the U.S. in more than 30 years. The Service has been working closely with the USDA to undertake sterile fly release operations in and around the refuge. As jaw-dropping as the beauty and splendor of the Keys are for most first time visitors, navigating the lands and waters that comprise the Florida Keys National Wildlife Refuges Complex takes seasoned practice. Coordination of the sterile fly releases twice weekly at 25 different sites on 12 separate islands is easier said than done; but it is a battle that must be undertaken in order to win the war on this less-than-welcome blast from the past.
Since November of 2016, Key deer deaths have slowed dramatically. As of this writing, the last Key deer lost due to NWS was on January 13, 2017. While the positive path continues, the Service continues this fight.
- Endangered Species Act
- Key Deer
- Florida Keys National Wildlife Refuges Complex
- Vero Beach
- New World Screwworm
The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. For more information on our work and the people who can make it happen, visit fws.gov. Connect with the Service on Facebook, follow our tweets, watch the YouTube Channel and download photos from Flickr.