As part of the global effort called Amphibian Ark (AArk), the Oregon Spotted Frog Recovery Team, which includes the Vancouver Aquarium Marine Science Centre and Amphibian Survival Alliance Partner Wildlife Preservation Canada, have recently released hatched tadpoles of one of the most endangered amphibians in Canada, the Oregon spotted frog, into the wild.[vc_row][vc_column width=”1/2″][text_output]
This is the fourth year the Aquarium has successfully bred this species, whose population has been in rapid decline in British Columbia and along the Western coast of North America. However, this year the number of tadpoles yielded has been lower than in previous years which is thought to be due in part to an unseasonably warm winter in the Lower Mainland.
Between 2010 and 2014, over 16,000 tadpoles and juvenile frogs produced in human care were released into suitable habitats to increase small existing populations in the wild.
For the first time since the program began, B.C.’S Oregon Spotted Frog Recovery Team recently found juvenile frogs in the wild, indicating that the tadpoles released in recent years are growing and healthy. The juveniles were found near Chilliwack, where they are released. Two established wild populations were also recently discovered in areas where the species was not previously known to be living. Egg masses were also discovered that are thought to have come from adult frogs the Recovery Team had released, a sign of the program’s success in supplementing and conserving the wild population.
“Finding juvenile Oregon spotted frogs in the wild are an encouraging sign that our efforts are having a positive impact on this endangered species. Discovering two additional established populations was also welcome news,” says Dr. Dennis Thoney, director of animal operations at Vancouver Aquarium Marine Science Centre. “These are important markers of a healthier population, although the road to recovery is a long one. One aspect we have to consider is warmer weather, such as the winter we just experienced, and how that alters the normal breeding patterns among not only Oregon spotted frogs, but other frog species as well.”
This year the program yielded fewer tadpoles than prior years, as changes in the environment and temperatures can create a disruption in normal hormone production and affect how the adult frogs respond to breeding.
The Oregon Spotted Frog Recovery Team has also observed significant variation in reproduction among the wild populations. Abnormal weather, such as more sunshine than usual, can lead to a rise in water temperatures in their natural habitats and trigger hormonal signals earlier – or later – than in a standard year.
Early last century, there were hundreds of thousands of Oregon spotted frogs, ranging from northern California up into British Columbia’s Fraser Valley. Due to habitat destruction and the introduction of non-native species such as Eastern Canada’s bullfrog and the reed canary grass, their numbers have declined as much as 90 per cent from past numbers in British Columbia. Historically, Oregon spotted frog populations had occurred throughout the Fraser Valley, from South Surrey to Hope. 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 first aquarium in the world to breed this species.
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.
Photos © Vancouver Aquarium[/text_output][/vc_column][vc_column width=”1/2″]
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