issues and experts

Endangered frogs: Getting the most bang for your conservation buck

January 24, 2018

Captive breeding may be a cost-effective strategy to reduce the extinction of critically-endangered amphibians when few other options exist. That’s according to a new study published in Ecological Economics by SFU ecologists Amanda Kisseland Wendy Palen, and B.C. Ministry of Environment conservation specialistPurnima Govindarajulu. The researchers studied Canada's most endangered amphibian, the Oregon spotted frog, which is found in only a handful of sloughs and wetlands in B.C.’s Fraser Valley. Each location harbours fewer than 500 frogs.

"We created a cost-benefit analysis model based on data from conservation strategies implemented by the B.C. Oregon spotted frog recovery team to supplement wild populations," says Kissel.

The team releases tadpoles or young frogs grown from either breeding adults in captivity, which is known as captive breeding, or from wild eggs that were collected and grown in captivity, known as head-starting.

The researchers found that captive breeding could reduce extinction risk by nearly four per cent for every $100,000 invested while head-starting may only reduce the risk by two per cent.

“These approaches are a last resort, and may have negative impacts we weren’t able to study, but we found that breeding 50 females in captivity could produce thousands of captive-bred tadpoles, which provides a larger boost to the population at a smaller cost than head-starting,” says Kissel.

“We found that head-starting wild eggs and releasing as tadpoles has a lower return on investment because survival is already high for eggs in the wild, and head-starting tadpoles and releasing as young frogs requires costly care.”

The researchers say decisions about how to recover imperiled species are complex and often made quickly. Making the wrong one can lead to the species blinking out of existence. They hope their findings can be used as a framework to support other recovery teams tasked with similar decisions. 


  • The study was conducted with the help of the Greater Vancouver Zoo, the Vancouver Aquarium and the Toronto Zoo.
  • Less than one per cent of the nearly 2000 species listed as threatened or endangered under the Canadian Species Act or U.S. Endangered Species Act have been successfully recovered.




Amanda Kissel, biological sciences,, 970-484-2898
Wendy Palen, biological sciences,, 415-548-3510
Wan Yee Lok, Communications & Marketing,, 778-782-3210