Conservation efforts for the local population of Oregon spotted frogs – the most endangered amphibian in Canada – are taking a leap in the right direction. In addition to encouraging findings from the field, the Vancouver Aquarium®, an Ocean Wise® initiative, raised and transferred 1,400 tadpoles to B.C.’s Fraser Valley on Tuesday, April 23. 1,240 tadpoles were released into a suitable native habitat and 160 were transferred to the Greater Vancouver Zoo where they will continue to grow before being released to the same site this fall. Working in close collaboration with Amphibian Ark (AArk) and the Oregon Spotted Frog Recovery Team, the Vancouver Aquarium has raised more than 21,000 Oregon spotted frog tadpoles for release since 2010.
This year, the Recovery Team saw promising signs of population increase at the release sites. While survey results are still coming in, early findings include juvenile and adult Oregon spotted frogs as well as egg masses at five of the seven release sites, one with a record high number. At the release site for Vancouver Aquarium-raised tadpoles, 23 juveniles and two small frogs believed to have been bred in the wild or been a surviving Aquarium-bred tadpole were found. Four of these frogs were third generation frogs born in human care – a first-time discovery for the Recovery Team. These findings are signs that tadpoles and frogs released in previous years are healthy and growing and the program is successful in supplementing and conserving the wild population.
“The early results from this year’s survey are really encouraging. While the frogs found are not of breeding age yet, this is a great indication that the tadpoles we’re releasing are maturing. We’re really hopeful that next year we’ll see egg masses at our release site,” says Kris Rossing, senior aquarium biologist at the Vancouver Aquarium, an Ocean Wise initiative. “Every year we learn more about the species, including its reproductive needs, which helps us continually refine and optimize our breeding practices and contribute to the wild population. At the same time, more and more people are learning about frogs, the important role they play in the ecosystem, and how we all can help with conservation efforts. While the road to recovery for the Oregon spotted frog will be long, these results let us know we’re on the right path.”
To further refine its frog breeding program, the Vancouver Aquarium aims to improve the fertility of the frogs in human care. Ongoing efforts include analyzing sperm samples of Vancouver Aquarium-raised frogs and wild frogs as well as establishing what ‘normal’ baselines are for wild frogs – an area that is not yet well studied.
Early last century, there were hundreds of thousands of Oregon spotted frogs, ranging from northern California up into B.C.’s Fraser Valley. Historically, B.C. populations were found from South Surrey to Hope but due to habitat destruction, the introduction of non-native species such as Eastern Canada’s bullfrog and the reed canary grass, increased pollution as well as disease, their numbers have declined as much as 90 per cent. Oregon spotted frogs spend most of their lives in the water and require connected wetlands and floodplains for habitat.
In an effort to protect this endangered species, the Aquarium joined B.C.’s Oregon Spotted Frog Recovery Team in 2000. A diverse group of biologists and land managers in B.C. are coordinating efforts to conserve, manage, and recover the Oregon spotted frog in Canada. Since 2007, Aquarium staff has been collecting Oregon spotted frog eggs to establish an Aquarium-based assurance population. In 2010, the Aquarium became the world pioneer to breed this species in human care.
The Oregon Spotted Frog Recovery Program includes habitat management, monitoring, research, and restoration conducted in partnership with the B.C. Ministry of Environment; B.C. Ministry of Forests, Lands, and Natural Resource Operations; Canadian Wildlife Service; Department of National Defense; Seabird Island Band; Stó:lo Tribal Council; District of Kent; Fraser Valley Regional District; Greater Vancouver Zoo; Toronto Zoo; Vancouver Aquarium; Mountain View Conservation Centre; Grouse Mountain Refuge for Endangered Wildlife; Wildlife Preservation Trust Canada; Simon Fraser University; University of British Columbia; B.C. Conservation Foundation; and Fraser Valley Watersheds Coalition.
The Vancouver Aquarium is also part of a worldwide effort, along with other zoos and aquariums, to conserve other amphibian species under the Amphibian Ark (AArk) project.
Ocean Wise would like to extend a special thanks to Teck Resources Limited for its support of the Oregon Spotted Frog Recovery Program.