Designated as a vulnerable species since 2000, the western chorus frog (Pseudacris triseriata) is the smallest frog species in Québec, measuring between 2.1 and 3.7 cm. The Biodôme is part of a collective working toward the recovery of this species, participating in a captive-breeding and reintroduction program.
Caring for the frogs
Animal health technicians at the Biodôme carefully tend to the Western chorus frogs raised in captivity, feeding them fruit flies, crickets, and waxworms (Galleria mellonella). Technicians then encourage breeding to support the frogs’ release into the wild.
Female frogs can lay up to 500 eggs in small clusters, attached to aquatic vegetation. Once the females lay their eggs and males fertilize them, the eggs are carefully transferred into small water tanks.
The embryos take between 3 to 14 days to develop into tadpoles, which are initially fed liquid algae, followed by fish food flakes.
Learn more about the efforts to conserve and breed this endangered species:
Reintroducing the western chorus frog into the wild
Each year, between 1,000 and 4,000 tadpoles and juvenile frogs are transferred to Mont-Saint-Bruno Park and Longueuil. As their legs develop and their tails disappear, the tadpoles gradually transform into froglets.
The complete metamorphosis of western chorus frogs takes 2 to 3 months.
A portion of the tadpoles that reach the froglet (or metamorphic) stage are tagged and released into specially designed natural ponds. Some are kept for breeding, while others are released later in the same ponds.
Tagging allows scientists to monitor the behavior of western chorus frogs in their environment once they transition to a terrestrial life and to estimate population density.
Learn how western chorus frogs are reintroduced at Mont-Saint-Bruno National Park:
A collective effort to support western chorus frog breeding
Western chorus frogs are found in the Montérégie and Outaouais regions, where they inhabit shallow wetlands such as ponds, ditches, and flooded clearings, which serve as its breeding grounds.
Due to habitat destruction, the western chorus frog population has declined significantly over the past several decades.
That’s why the Biodôme, the Ministry of the Environment, the Fight Against Climate Change, Wildlife and Parks (MELCCFP), and other partners are working with the Western Chorus Frog Recovery Team. The goal of this collaboration is to develop expertise in captive care, hibernation, breeding, and the long-term maintenance of a captive population.
Wild adult individuals are first captured by MELCCFP staff during the breeding season. The amplexus (mating technique) then takes place at the Biodôme, with or without hormonal assistance. A portion of the offspring will be released into the wild.
The knowledge gained from this conservation program will be valuable in the event of a significant decline in western chorus frog populations in their natural habitat.
Likewise, the assisted reproduction of western chorus frogs at the Biodôme and their release into wetland environments help support the survival of this at-risk species.