Abstract

The distribution area of the copper redhorse (Moxostoma hubbsi), a critically endangered species of Catostomidae, is limited within a few rivers of the province of Quebec, Canada. A reintroduction program, involving fingerlings stocking from a field artificial breeding and a hatchery-rearing program, was initiated by the provincial wildlife agency. In 2012, fingerlings were obtained by the Aquarium du Québec for research and education purposes. These fingerlings were fed a diet composed of trout chow (Corey 0.7–1.0), bloodworms, Mazuri® Omnivore Aquatic Gel Diet (Formula #5ML6a), krill, aquatic snails, supplemented with vitamins E and C. Following the detection of vertebral deformities in a few of the larger individuals, the vitamin supplementation was increased (total of ≈2000 IU of vitamin E and 4000 mg of vitamin C/kg of food). A decrease in the growth rate was also achieved by mimicking natural seasonal fluctuations in water temperatures. Following these changes, no new cases of vertebral anomaly have been observed. During the first three years (2012–2015), the estimated annual growth of 70% obtained was lower than data available for wild redhorse species. Since 2015, fish have been fed a pelleted diet (Vitalis, World Feeds) which has been associated with an annual growth of 18%, which is similar to growth curves documented in wild redhorses of that age class. In fall 2019, six surplus fish were implanted with acoustic transmitters and released in the Richelieu River. These tagged fish could provide inestimable information on the displacement, behavior, and survival of age 7+ stocked copper redhorse.

Acknowledgments

The authors wish to thank the animal care team of the Aquarium du Québec that have worked with these fish as well as the Équipe de rétablissement du chevalier cuivré du Québec for their support with the transmitter implantation. We are also thankful to the Baldwin-Coaticcok provincial hatchery for egg incubation and rearing of the species during the first months.

*Presenting author