Approximately 1,000 endangered northern leopard frog tadpoles just made the leap – metaphorically speaking – from the Vancouver Aquarium to the Kootenays. As tadpoles, of course, their jumping abilities are limited, but these representatives of B.C.’s most endangered amphibian species are well on their way to the kind of natural development that’ll put a spring in their “step.”
Raised at Vancouver Aquarium®, an Ocean Wise® initiative, the school of tadpoles travelled by plane to Cranbrook, B.C., courtesy of London Air, and then via two-hour car ride to their new home in the marshy wetlands along the Columbia River, near the Alberta border.
This is the seventh consecutive breeding year for the conservation program, which aims to increase the wild population of the northern leopard frog, once commonly found in the Kootenays and the Okanagan. Research continues into the reasons for the steep decline in their population starting in the 1970s. At one point, there was only one known population of northern leopard frogs remaining, in B.C.’s Creston Valley.
To combat this steep decline, since 2013, the Vancouver Aquarium has collaborated with the Northern Leopard Frog Recovery Team to raise and release more than 8,100 northern leopard frog tadpoles. There are certainly challenges. Changes in the environment affect the frogs and their reproductive cycles, both in the wild and at the Aquarium. That means the egg masses and tadpole numbers aren’t consistent.
“This year was particularly dry, and the frogs are very much affected by rainfall and the associated pressure fronts,” said Kris Rossing, senior biologist at Vancouver Aquarium. “Every year we strive to learn more about these frogs and their reproductive needs, which helps us continually refine our propagation practices and maximize the impact of our conservation efforts.”
Because this project has continued for seven years, many of the northern leopard frogs produced at the Vancouver Aquarium have had time to reach maturity. The Recovery Team has observed at its Brisco, B.C., release site that many adult frogs have survived the cold months and been able to mature sexually, so they can mate and add to the vulnerable Rocky Mountain population. (Northern leopard frogs are not a species at risk in Eastern Canada, and the population and range of the prairie leopard frog has increased sufficiently that it has been down-listed from endangered to “at risk” by the Committee on the Status of Endangered Wildlife, or COSEWIC .)
The Vancouver Aquarium’s propagation project has involved collaborating with the University of Ottawa’s Dr. Vance Trudeau, who created a hormone treatment called Amphiplex. A painless injection into the frogs induces spawning and encourages the amphibians to engage in amplexus, the process by which a male mounts a female and holds her to induce ovulation, then fertilizes the eggs.
The Vancouver Aquarium was the first aquarium to breed the amphibians as part of an assurance population. It’s part of a worldwide effort, along with other zoos and aquariums, to conserve this and other amphibian species under the Amphibian Ark (AArk) project.