Razorback Sucker

DESCRIPTION:
Razorback Sucker is laterally compressed with a distinctive keel behind the head in specimens larger than 10 in (25 cm). Color is olive to brownish-black on the back, yellowish to yellow-white on the belly. Breeding fish especially males, may have a rosy lateral stripe and bright yellow-to-orange belly. Breeding tubercles may develop in both sexes, more so in males, and females often have a distended genital papilla (externally extended and fleshy genital opening). This species is adapted to warm, turbid waters and exhibits a long lifespan, with individuals exceeding 40 years of age.

DISTRIBUTION & STATUS:
Razorback Sucker currently occupy isolated regions of the Colorado River basin. Nearly all razorback suckers encountered throughout the basin today are survivors of stocking programs. A small (less than 1000 fish) population with detectable recruitment occupies Lake Mead including parts of western Grand Canyon. Dam construction in the basin reduced peak flows, changed temperature regimes, created reservoirs, and disconnected floodplains from the mainstem rivers. Altered environments provided opportunities for non-native fish to flourish. Non-native predators consume all stages of Razorback Sucker, preventing natural recruitment, and reducing survival of stocked fish. In response to population declines, the species was stocked widely in the Colorado River and its tributaries, backwaters, and connectives plus into urban lakes and other artificial waters. Today, large scale stocking of Razorback Sucker in the lower Colorado River basin is restricted to the mainstem Colorado River with a few experimental stockings elsewhere. The razorback sucker was officially listed as federally endangered under the Endangered Species Act in 1991.

HABITAT:
Today the species occupies reservoir and riverine habitats. Adult razorback sucker persist in small pond environments, large reservoirs, and flowing rivers. Razorback sucker are commonly found near sand, mud, and large rocky substrates in areas with low/medium water velocity.

FOOD HABITS:
Razorback sucker are opportunistic omnivores eating insects, plankton, and plant matter.

REPRODUCTION:
Razorback Sucker is a seasonal spawner, relying on hydrological and thermal cues to reproduce on gravel or cobble substrates, where adhesive eggs are laid. Razorback Sucker aggregate at distinct locations each winter-spring by the hundreds to thousands. Aggregations form near spawning locations, and females will leave the aggregate to mate with one or more males over the spawning bed. There is no parental care, the spawning adults leave the eggs soon after spawning, and both the eggs and larvae are highly susceptible to predation by invasive fishes including carp, sunfishes, and bass.