Tadpoles of Endangered Northern Leopard Frogs To Be Released After Successful Breeding Season at Vancouver Aquarium

Vancouver, B.C. – The Vancouver Aquarium Marine Science Centre, as part of the B.C. Northern Leopard Frog Recovery Team, will be releasing tadpoles after successfully reproducing the endangered frog for the fourth year in a row. Vancouver Aquarium was the first aquarium to breed B.C. Northern leopard frogs as part of an assurance population and is part of a worldwide effort, along with other zoos and aquariums, to conserve this and other amphibian species under the Amphibian Ark (AArk) project.

However, the number of tadpoles has decreased over the last two years, thought to be attributable to warmer weather during the winters. The higher temperatures delay or halt the frogs from entering hibernation, and their bodies continue to operate as normal, or in a fully metabolic state. As a result, they are burning through their fat stores at a much more rapid rate than they normally would in a winter with cooler, or average, temperatures.

“Typically, when frogs come out of hibernation their bodies send a signal that it’s time to begin breeding. With the warmer temperatures we’ve experienced, however, that process is slower to start or not happening at all, and resulting in a lower number of tadpoles being produced,” said Kris Rossing, senior biologist at the Vancouver Aquarium.

The tadpoles, which hatched in the last week, will be released into the wild by the Northern Leopard Frog Recovery Team in the Columbia Marshes near Cranbrook, B.C. Since the program began in 2013, the Vancouver Aquarium’s frog propagation program has introduced more than 5,000 tadpoles to this site.

“Releasing 500 tadpoles this year is a key step on the road to recovery for the Northern leopard frog in the wild. Frogs are indicators of overall environmental health and play an integral role in their ecosystems. The Vancouver Aquarium is dedicated to conserving aquatic life and many amphibian populations, facing a perilous future, are in need of protection,” added Rossing.

In the 1970s, populations of Northern leopard frogs across western Canada declined by the millions. This drastic drop in population made them one of the most at-risk amphibian species, especially in British Columbia. Scientists continue to research the cause of these sharp declines in the Rocky Mountain population of the Northern leopard frogs. The Rocky Mountain population that occurs in B.C. is listed as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC), and is on the provincial Red List.

The Rocky Mountain population of Northern leopard frogs are the most at-risk amphibians in B.C. This population was once found at many sites in the Kootenay and Okanagan regions, but their numbers in western Canada fell to a point where only one wild population existed – in the Creston Valley. In 2004, a second population was reintroduced in the Upper Kootenay Floodplain, near
Bummers Flats, as part of the recovery effort for this species. In 2013, a third population was reintroduced at the site in the Columbia Marshes, representing another small step in the recovery of the species.

Unlike the Rocky Mountain population, the Prairie Northern leopard frogs have reoccupied some of their former range on the Prairies, and these populations are now considered to be of special concern by COSEWIC. Northern leopard frogs in eastern Canada are classified as not being at risk.*

The Northern Leopard Frog Recovery Team implements conservation actions as outlined in the Northern Leopard Frog recovery strategy.

Vancouver Aquarium

The Vancouver Aquarium Marine Science Centre is a non-profit society dedicated to the conservation of aquatic life. www.vanaqua.org.

*According to the B.C. Frogwatch Program.

Editors: Photographs of Northern leopard frog tadpoles and adults area available.


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Alexis Brown
Ocean Wise
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