Hatchery Breeds Wyoming's Rarest Toad

Article excerpt

Detroit. Toledo. Cincinnati. New York City. Saratoga. They all hold captive populations of an endangered amphibian, the Wyoming toad (Bufo hemiophrys baxteri). Small captive populations of the rare toad live in eight city zoos across the country, all participating in the American Zoo and Aquarium Association's Species Survival Plan (SSP), a systematic arrangement to keep the toad from going extinct. But it's near a small Wyoming town where the Saratoga National Fish Hatchery has one of the largest captive populations, which should contribute in large measure to the toad's recovery.

The Wyoming toad's natural range is within roughly a 30-mile (48-kilometer) radius of Laramie. Following a population crash, the toad was listed as endangered, and most of its habitat is now protected as part of the Mortenson Lake National Wildlife Refuge. As is the case with most listed species, the major factor behind the decline was habitat loss. Irrigation out-competed wetlands for water, and matters were made worse by continued drought. Sensitivity to herbicides was a factor, too. Then there's the chytrid fungus (Batrachochytridium dendrobatidis). Chytrid infections seem to play a large role in suppressing the animal, says David Paddock, the lead toad biologist at Saratoga NFH.

As part of the recovery program, Wyoming toads were brought to the Saratoga NFH for propagation. Captive breeding began in earnest in 1999. Since that time, an average of 6,863 Wyoming toads have been released each year. Between 1999 and 2003, Saratoga produced an average of 55 percent of the toads released to face the rigors of the wild in the Laramie basin. Just last year, tadpoles from Saratoga were released onto two new private land sites covered under Safe Harbor Agreements, a wonderful arrangement made possible by the Service's Cheyenne Ecological Services Office and the Laramie Rivers Conservation District.

The Saratoga facility also produces trout for restoration into the wild. Paddock is a fish biologist by training and a toad biologist by necessity. But he says animal husbandry is much the same, whether for trout or amphibians. He keeps toads at the hatchery carefully isolated from the fishes in their own environment, and he adheres to strict protocols to prevent the spread of chytrid fungus or other disease-causing pathogens. Toads with chytrid are cared for with antifungal treatments.

He says it's easier to get the toads tO breed than one might expect. Of the 150 adult toads kept on station, breeding pairs are carefully selected from a studbook--one used by all the participating zoos in the SSP--to maintain genetic integrity. …