Overview
The Greater Redhorse (Moxostoma valenciennesi) is the undisputed giant of the redhorse genus, reaching lengths of over 30 inches and weights exceeding 12 pounds. Native to the northern glacial river basins of the Great Lakes and St. Lawrence watersheds, this majestic golden fish was named in honor of legendary French zoologist Achille Valenciennes and is a prime indicator of pristine aquatic integrity.
Biology and Physical Characteristics
The Greater Redhorse is recognized by its robust, deep-bodied profile, prominent brassy-golden to bronze scales, and striking blood-red caudal fin. It has a blunt, rounded snout and a large subterminal mouth with plicate lips that have a smooth, non-notched posterior margin. Breeding males develop prominent rows of white nuptial tubercles across their snout and anal fin.
Behavior and Ecology
Inhabiting deep, clear pools and boulder-strewn runs during summer, the Greater Redhorse moves onto swift, shallow gravel riffles in late spring (May and June) to spawn. Spawning trios consisting of two males flanking a single female thrash together over gravel beds, burying thousands of eggs in the clean stones before returning to deep sanctuaries.
Conservation and Human Impact
Assessed as Least Concern by the IUCN, the Greater Redhorse is considered rare and vulnerable across much of its southern periphery in the United States. Its absolute intolerance to water turbidity, silt accumulation, and municipal chemical pollution makes it one of the first species to disappear from degraded rivers.
Interesting Factoid
The Greater Redhorse is the largest species of redhorse sucker in the world, living for three decades and growing to the size of a prize salmon in clear northern rivers.