Hormone profile monitoring and reintroduction site water quality assessment to support conservation of the Oregon spotted frog (Rana pretiosa)

The main goal of this research was to enhance the endangered Oregon spotted frogs (OSF) captive rearing methodologies and better understand the sensitivity of early life stages to various water quality changes. A key finding was that significant seasonal variations in estradiol and testosterone levels were evident in OSF between two British Columbia captive rearing facilities, indicating different captive rearing conditions may be influencing reproductive status in captive OSF. Larval OSF are more sensitive to the lethal effects of acute, waterborne copper exposure than any early life stage amphibians or fish studied to date. Finally, larval survival was significantly lower in OSF reared in captive waters followed by transfer to reintroduction site water, suggesting an increased survival rate may be achieved by acclimating OSF to reintroduction site water prior to release into the wild. This research provides critical insights for enhancing OSF captive breeding programs and reintroduction strategies.