This week, Kris Rossing, Senior Ocean Wise Biologist at the Vancouver Aquarium, headed out to Salmon Arm to meet the Ministry of Forests, Lands and Natural Resources where they will release over 2 000 Northern Leapord frog tadpoles into freedom at a rate that exceeded all expectations.
This year all the frogs at the Aquarium have successfully spawned, with the number of tadpoles much higher than average, reaching over 2000.
This is the seventh consecutive breeding year for the Vancouver Aquarium/Ocean Wise conservation program that aims to boost the wild population of the Northern leopard frog – the most endangered amphibian in British Columbia – and the largest number of tadpoles produced in a single year. In collaboration with the Northern Leopard Frog Recovery Team, staff at the Vancouver Aquarium have raised and released more than 7,100 Northern leopard frog tadpoles since 2013.
For over six years, Northern leopard frogs bread at the Vancouver Aquarium have been dedicated to re-establishing a wild population near Brisco, B.C. For the past few years, the Northern Leopard Frog Recovery Team has heard adult males calling at this release site; this is a positive indication that the frogs are surviving winter and reaching sexual maturity, and that the program is successful in helping this vulnerable population.
Vancouver Aquarium was the first aquarium to breed these amphibians 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.
A key component of the propagation process involves a collaboration with Dr. Vance Trudeau at the University of Ottawa and the use of a hormone treatment he created called Amphiplex. The treatment, which is a painless injection into the frogs, has been used to help induce spawning and spur the animals into amplexus — when the male mounts and holds the female frog to induce ovulation and then fertilises the eggs as they are laid.
Beginning in the 1970s, populations of Northern leopard frogs across western Canada declined by the millions, making them one of the most at-risk amphibian species, especially in B.C. Research continues into 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.
Once found at many sites in the Kootenay and Okanagan regions, the Rocky Mountain population began to decrease to a point where only one wild population, in Creston Valley, existed. In 2004, a second population was reintroduced in the Upper Kootenay Floodplain, near Bummers Flats. A third population was reintroduced in 2013 at a site in the Columbia Marshes with tadpoles produced at Vancouver Aquarium as part of the recovery effort for this species.
There are two other populations of Northern leopard frogs in Canada; the Prairie Northern leopard frogs have reoccupied some of their former range on the Prairies, and as a result have been down listed 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.