Omaha's Zoo and Aquarium sends 10,500 endangered tadpoles to Puerto Rico

The eggs hatched on July 3, at Omaha's Henry Doorly Zoo and Aquarium's Amphibian Conservation Area.

Four breeding pairs were injected with hormones during amplexus, or mating, to increase fertility.

More genetically viable and diverse adults were present among the Zoo's population of the species this mating season, enabling Zoo staff to breed more than the traditional one pair.

The eggs produced were laid in strings and hatched within 48 hours.

Eighty of the tadpoles, 20 from each pair, remained at Omaha's Henry Doorly Zoo and Aquarium to strengthen the North American population within institutions accredited by the Association of Zoos and Aquariums (AZA).

The Zoo is one of 19 AZA certified institutions that participate in the breeding program for the species.

The Amphibian Conservation Area, a non-public facility that quarantines amphibians and carries out these programs, houses a majority of the Zoo's Puerto Rican crested toads, in addition to eight other threatened and endangered amphibian species. Seven adult Puerto Rican crested toads are currently on display to the public in the Zoo's nocturnal exhibit, Kingdoms of the Night.

Puerto Rican crested toads, the only toads native to Puerto Rico, are listed as critically endangered on the International Union for Conservation of Nature's Red List of Threatened Species due to habitat destruction, human encroachment and the introduction of invasive animal species.

In 1984, the toad species became the first amphibian Species Survival Plan program under AZA and is the longest continuous running reintroduction program for an amphibian species.

For the past 35 years, wild populations have fluctuated from 300 to approximately 3,000 individuals.

The Amphibian Conservation Area at Omaha's Henry Doorly Zoo and Aquarium is a space designed to house and breed amphibians threatened with extinction and is capable of holding up to 50 different species.

Individual, bio-secure isolation rooms are set up for each species to prevent the spread of disease between specimens.

Each unit has its own heating and cooling unit and is completely sealed. Strict hygiene procedures are practiced by the keepers to prevent contamination.