Florida Keys

Fewer Key deer are dying from screwworm, but more are being killed by cars

More Key deer are being hit and killed by cars.
More Key deer are being hit and killed by cars. emichot@miamiherald.com

The population of endangered deer found only in the Florida Keys has taken a significant hit from both New World screwworm and cars.

The population is now estimated to be in the high 600s for deer living on Big Pine and No Name keys, according to Dan Clark, manager of the National Key Deer Refuge. The number does not include other Lower Keys islands where deer live.

The estimated pre-screwworm population was 875, Clark said. It was previously estimated at 1,000 and determined through monitoring deer on Big Pine, No Name and other keys.

Officers haven’t euthanized an endangered Key deer since Nov. 15. The number of dead deer due to the worms that eat away at living tissue since early July has remained at 132 and 51 deer have also been killed by cars since then. There have been 13 deer killed by cars since Nov. 15, however.

“Unfortunately we see a little uptick in deer accidents with more people and cooler weather, so it’s standard this time of year,” Clark said.

Reproductive organs have been collected from 23 deceased Key deer should the need arise to preserve the species.

The reproductive organs are sent to the South-East Zoo Alliance for Reproduction and Conservation’s White Oak Center, north of Jacksonville, to preserve testicles and ovaries if needed later. They are frozen cryogenically for possible future extraction of DNA. It’s not clear how that could be used to create a new deer herd.

Clark said the focus on the refuge has been monitoring the deer and extinction isn’t a major concern at this point.

As of Friday afternoon, Oct. 14, 2016, 83 endangered Key deer had been euthanized because of an infestation of the New World screwworm. The screwworm, not seen in the U.S. since the 1960s, is leaving open wounds on the deer and then eating the fle

The rate of death has been slowing down because doramectin, an antiparasitic medicine that serves as a preventive measure and treatment for screwworm, has been given to deer since mid-October. As of Friday, 4,089 doses had been administered to the deer. Included are 1,404 deer that have self-medicated at 21 stations where they feed on doramectin-soaked food, Clark said.

Sterile screwworm flies are also being released to mate with wild flies to produce offspring that never hatch. There are 25 release sites in the Lower Keys and four in Marathon. As of Friday, more than 40 million had been released, Clark said.

After monitoring flies on the refuge since the sterile screwworm fly release began, no fertile screwworm flies have been found since Nov. 6.

Katie Atkins: 305-440-3219