Overview
The Black Redhorse (Moxostoma duquesnei) is an exceptionally sleek, cool-water freshwater fish native to the pristine upland streams of eastern North America. Named for its dark, slate-grey to dark olive dorsal coloration and silvery flanks, it was named by French naturalist Henri de Blainville in honor of Fort Duquesne (modern-day Pittsburgh, Pennsylvania).
Biology and Physical Characteristics
The Black Redhorse is recognized by its slender, elongated body profile—narrower than most other redhorses—and its dark olive to slate-grey back with subtle blue-green iridescence. Its caudal and dorsal fins are dark slate-grey with pale margins. Its downward-facing mouth features fleshy plicate lips that have a straight, uninterrupted posterior border, specialized for delicate vacuuming of gravel surfaces.
Behavior and Ecology
A specialist of cool, fast-flowing water, the Black Redhorse prefers clear upland streams with swift riffles and deep rocky pools. Each spring as water temperatures reach 15°C, adults migrate upstream into tributary headwaters, gathering in aggregations over clean gravel shoals to spawn in turbulent, oxygenated currents.
Conservation and Human Impact
Classified as Least Concern globally, the Black Redhorse is nonetheless classified as threatened or endangered in several states along its northern and western peripheries (including Ontario, Michigan, and Wisconsin). Extreme sensitivity to water temperature increases, agricultural siltation, and dam construction makes it a sentinel species for stream degradation.
Interesting Factoid
The Black Redhorse requires the cleanest, coolest water of all redhorse suckers; if a forest stream becomes muddy or warms up from clear-cutting, this sensitive fish is the very first species to vanish.