After an outstandingly cold and snowy winter, the Oregon spotted frogs – the most endangered species in Canada – were off to a slow start. However, under the care of senior aquarium biologist Darren Smy, the Vancouver Aquarium has had a successful frog breeding season for the eighth consecutive year. In early May, the Aquarium released more than 1,000 Oregon spotted frog tadpoles into the wild bringing the total count to almost 20,000 tadpoles released since 2010 in a collaborative conservation effort.
“The prolonged winter conditions delayed egg mass production as well as tadpole growth both in the wild and here at the Aquarium,” says Smy. “But the milder spring conditions have had an accelerating effect and tadpole development and our release was on target.”
Changes in the environment and temperatures can create a disruption in normal hormone production and affect how the adult frogs respond to breeding; this results in varying timelines as well as numbers of egg masses and tadpoles produced each year.
Early last century, there were hundreds of thousands of Oregon spotted frogs, ranging from northern California up into B.C.’s Fraser Valley. 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.
In an effort to protect this endangered species, the Aquarium joined 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 first in the world to breed this species in human care.
“After eight successful years of breeding these endangered frogs, we are nearing 20,000 tadpoles that have been released into the wild, playing a vital role in rebuilding a population that is in dire need. Without this collaborative conservation program in place, the Oregon spotted frog would be facing an uncertain future in B.C.,” adds Smy. “While the road to the recovery of the Oregon spotted frog will be long one, every year we learn more about the reproductive needs of Oregon spotted frogs which helps us continually refine our practices and maximize the impact of our conservation efforts.”
In recent years, the Oregon Spotted Frog Recovery Team found juvenile frogs as well as egg masses thought to have come from propagated frogs near a release site – both indications that tadpoles and adult frogs released in previous years are healthy and growing. The Recovery Team has also discovered four additional established wild populations – two in 2015 and two in 2017 – bringing the total to seven. These discoveries are signs of the program’s success in supplementing and conserving the wild population.
The Oregon Spotted Frog Recovery Program includes habitat management, monitoring, research, and restoration that is 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.