Frogs and PIT tags… must be fall!
Posted onOctober 14, 2025byJenna Kissel|Fraser Valley Wetlands, Fraser Valley Wetlands Wildlife, News and Events, Oregon Spotted FrogPhoto: J. Kissel.
What is the Oregon Spotted Frog Recovery Program? Since 2010, WPC has been breeding the endangered Oregon spotted frog at the Greater Vancouver Zoo, and reintroducing thousands of tadpoles and froglets back into wetlands in B.C.’s Fraser Valley. It takes years of careful observation, collaboration, ingenuity and sometimes a little luck to crack the code to breeding specific species. For several years, our progress was very limited. But our team persevered. Today, WPC has pioneered breeding techniques that are turning the tide for this species.
The hustle and bustle of the summer season has come to a close, and Andrea, WPC’s Lead Biologist for B.C. Projects, and I are preparing for the slower pace of fall. Before we can settle into routine cleaning and report writing, there is one last day of chaos – frog marking day.
On frog marking day we and a team of volunteers, including our partners from the provincial government, process, and tag all the Oregon spotted froglets that hatched in our conservation program this year, in preparation for release. We also release them on the same day to minimize the stress of handling. As we collect the froglets we break down their tubs by draining the water and removing their floating islands. This does make the tiny frogs easier to find, but we still have to carefully pick through the moss to make sure we haven’t missed anybody! Once we’ve collected all the froglets we can start processing them. We take body measurements including snout to vent length, shank length (the leg length between the knee and ankle) and we weigh them. Then each froglet is given an ID tag.
Oregon spotted froglet being processed. Photo: J. Kissel.
If the froglet is over 8 grams, it gets a PIT tag. PIT (passive integrated transponder) tags are very similar to the microchip your dog might receive at the vet. We can use a PIT tag reader (pictured below) to scan any frogs we may recapture in the future and know exactly who they are. If the froglet is under 8 grams, it gets a Visible Implant Elastomer (VIE) tag, which is a brightly coloured liquid that gets injected in-between the froglet’s toes. This liquid solidifies once injected but remains flexible and visible through the skin. VIE tags don’t identify individuals, but they can tell us that the froglet came from our conservation breeding program.
PIT tag readers are used to scan recaptured frogs and identify them by their tag number. Photo: J. Kissel.
Due to lower successful fertilization of the eggs this year (possibly due to some male frogs who sneakily spent last winter in the female tub, and because there are younger females in the breeding program), we had a lower number of offspring to release, with about 100 froglets joining the 3,500 tadpoles that were released earlier this spring.
Oregon spotted froglets about to be transferred to the release site. Oregon spotted frog tadpoles and froglets born in our breeding program at our Conservation Lab located at the Greater Vancouver Zoo are released at restoration sites near Agassiz, where the few wild populations of Oregon spotted frogs remain. Historically, these frogs were found within the Fraser River Lowlands, but with significant habitat loss due to urban development, agricultural land conversion, and other land-use changes, remaining populations have become isolated and confined to less-than-ideal habitat. Other threats they face include competition from invasive species such as bullfrogs, disease, and environmental stressors such as water temperature changes and pollutants. Photo: J. Kissel.
Our long-term goals at WPC are to prevent the endangered Oregon spotted frog from disappearing by continuing to support wild populations through conservation breeding and release, population monitoring, and research. Releasing conservation-bred tadpoles and froglets helps supplement the wild populations, and ultimately, we are hoping to establish new wild populations to further support Oregon spotted frog recovery.
Jenna Kissel
Conservation Programs Assistant – B.C. Projects
Jenna joined WPC as a conservation programs assistant, supporting the western painted turtle, Oregon spotted frog, and Taylor’s checkerspot butterfly programs. She graduated from the University of Guelph with a BSc in Wildlife Biology and Conservation and has a background in avian husbandry and propagation. She spent several years in spotted owl conservation and is looking forward to continuing her work in endangered species recovery as part of the BC Projects team.
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