The Black Redhorse is a fish species that is a member of the sucker family. They are about 50 cm long and can weigh up to 1 kg. The Black Redhorse is generally grey-silver in colour, but they can have undertones of dark grey, brown, olive-brown, or silver-blue along their spine. Along the sides of the Black Redhorse has colour tones of silver-blue, and their bellies are white or cream. They have slate grey fins but the bottom ones can also have an orange-rust colour to them. The Black Redhorse also has a long, upturned snout with a sucker-like mouth.
The Black Redhorse is a benthic feeder, which means they are a bottom feeder. They forage on the bottom of rivers in the sediment looking for crustaceans, algae and aquatic insects. Juvenile Black Redhorse will feed primarily on plankton.
Biology and Behaviour:
Black Redhorse fish mature around the age of 5. Migration upstream to their breeding grounds begins around April when temperatures stay above 10°C. Spawning season will occur in late May, and while the females do not change, male Black Redhorse will change color from blue-silver to green-black. The female will lay anywhere between 4,000 and 12,000 yellow eggs that are no larger than 3 mm, and then the male will fertilize them. They are placed in low current areas over fine gravel or small rock sediment areas. Eggs can take around 180 days to hatch, where they will remain in the area until they grow large enough to find suitable habitat and feeding grounds. Exact predators are unknown, but they are expected to be larger fish species and raptors.
Golden Redhorse look very similar to the Black Redhorse, but Black Redhorse have larger lateral scales that do not overlap. They also have 9 lower pelvic fins instead of 10. You can also tell the difference between the Black Redhorse and other Redhorse species by their tail. The Black Redhorse has a slate grey tail, while other species like the River Redhorse, Copper Redhorse, Shorthead Redhorse, and Greater Redhorse have a red tail.
Conservation and recovery strategies:
The Black Redhorse and their habitat are protected under Ontario’s Endangered Species Act, and indirectly protected by the federal Fisheries Act. However, there are currently no recovery strategies in place for this species, since this species lacks sufficient scientific research. While the Black Redhorse is considered a “least concern” species globally and is generally safe, the only populations in Canada occur in Ontario, and these populations are considered close to Extirpation. Conservation and recovery strategies should be put into place for the Canadian population, starting with increased research and creating a plan for recovery.
Government of Ontario. 2014. Black Redhorse. Retrieved from: https://www.ontario.ca/page/black-redhorse
COSEWIC. 2015. COSEWIC assessment and status report on the Black Redhorse Moxostoma duquesnei in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xii + 50 pp. https://publications.gc.ca/collections/collection_2016/eccc/CW69-14-220-2015-eng.pdf
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