2 ½ feet long and 10 pounds

This prehistoric fish is distinctively adapted to the Colorado River. Large scales, sleek body and a pronounced keel on its back, just behind the head allowed it to negotiate the fast and turbulent water of the big, muddy violent currents that existed in the river prior to the construction of major hydroelectric dams along the river corridor. It has the classic down-turned sucker mouth for feeding off the bottom of the river and large, round eyes.

Up to 40 years

Historic habitat was the turbid waters and quiet, muddy backwaters of the Colorado and Green River systems.

Historic range for the razorback sucker was from the Yuma, Arizona stretch of the Colorado River to the upper reaches of all the main stem and tributaries of the Green and Colorado River systems.

Their present range is restricted to Lake Mojave, below Hoover Dam.

Specific adaptations allowed the razorback sucker to thrive in the sometimes violent, sometimes bleak flows of the wild rivers of the intermountain states. As annual floods brought silt into the slow bends of the rivers, it deposited long spits of sand. These created backwaters with limited flows and cloudy water that provided perfect nesting and nursery habitat. Once the fry reached viable size, off they went to join other native fish in the mainstream of the river. In the spring, as floods renewed the silt deposits and backwaters, adult razorback suckers would migrate upstream to the backwaters to nest and lay their eggs.

Like other suckers, razorback suckers are scavengers, feeding on the dead animals and microinvetrabrates on the bottom of the pools and backwaters of the river.

Razorback suckers achieve sexual maturity at about age 10 or 11. As she is laying her eggs along the bottom of the backwater, the male sidles up alongside and together they shimmy along the bottom, the male fertilizing the eggs as they are laid. The eggs hatch and fry remain in the backwater protected from predators by the cloudy water, until they are ready to swim out into the river.

Endangered

The first major decline in populations was noted in 1941, throughout the entire river system. Construction of dams cut migration routes, flooded some of the habitat and cleared up the tailrace water, robbing it of the silt, which built the protective backwaters. Game fish and other non-native fish were introduced, which compete with native fish and prey on the fry. In some cases, native fish were eradicated in order to make way for game fish introductions.

Stocking and reintroduction efforts have proven fairly unsuccessful, because of predation on the small stocked fish. Isolated populations have been successfully reared to adult stage in pools cleared of other fish. But, these are small populations and not connected with the last viable group in Lake Mojave, so chances of total population survival by this method are bleak. New methods of rearing and stocking adult fish are being tried and hold some potential for maintaining existing populations. But, without their critical habitat, the future is not bright for a full recovery.

Like the other native fish of the Colorado River, the razorback sucker is a holdover from prehistoric times, a living fossil. For the first 10,000 years of human existence, the razorback sucker had a longer average life span than a homo sapien.