10 | 2017 LAKE STEWARDS NEWSLETTER Asian carp by Becky Cudmore About this Fish Asiancarpsareagroupoffourspeciesoffishintheminnow family, native to China and Russia, which include: Grass, Bighead, Silver, and Black carps. They were originally brought to North America in the 1970s to control algae and other pests in fish farms. As a result of flooding, the fishes were able to escape the fish farms and find their way into the Mississippi River system, and have been spreading north towards the Chicago Area Waterway System (CAWS), which outlets into Lake Michigan. The climate of their native range is similar enough to that of North America that they have successfully invaded much of central and eastern U.S.A and would be successful across Canada should they arrive. Distribution & Habitat Asian carps prefer cool to moderate water temperatures, although some species, like the Grass Carp, can tolerate temperatures up to 38°C. They are generally found in large, slow-moving river reaches and lakes. These habitat types are abundant in the Great Lakes area. Life Cycle Asian carps are thought to prefer to spawn in long (100 km or longer), undammed rivers with moderate flow. Spawning is triggered by warming water temperatures and a sudden spike in flow. Asian carps produce a large number of eggs; for instance, one female Bighead Carp may release as many as 1.9 million eggs in a year. The eggs are fertilized upstream, and develop as they drift downstream. Wetlands at the mouth of the river are required to provide sheltered nurseryhabitatforthenewly-hatchedfishtogrow.However, scientists are starting to see differences in spawning behaviours in North America from those in their native range. For example, spawning has been observed in slower- moving backwater habitats and narrower watercourses than scientists originally thought, and they may be able to reproduce more frequently and at a younger age than in their native range. David Marson, biologist with the Asian Carp Program, holding a Grass Carp captured in Jordan Harbour, Lake Ontario in August 2015 during early detection surveillance efforts. Cottagers! Cottagers! ATTENTION Make sure you and your guests know the Invasive Species Action Plan to keep invasives away from your cottage. ontario.ca/page/cottager-action-plan