Colorado pikeminnow (Ptychocheilus lucius)

The Colorado pikeminnow is the largest minnow in North America and is an endangered, native fish of the Colorado River thought to have evolved more than 3 million years ago. Called the “white salmon” by early settlers due to its migratory behavior, the Colorado pikeminnow has a torpedo-shaped body and a large, toothless mouth. It has an olive-green and gold back and a silvery-white belly.

Colorado pikeminnow can live up to 40 years and were historically known to grow to nearly 6 feet long and weight 80 pounds. Today, researchers commonly see adult Colorado pikeminnow that are 2 to 3 feet in length. Colorado pikeminnow are known for long-distance spawning migrations of more than 200 miles in late spring and early summer. They are capable of reproducing at 5 to 7 years of age. Young Colorado pikeminnow feed on insects and plankton, whereas adults feed mostly on fish.

The Colorado pikeminnow was a valued food source by early settlers. Dale Stewart of Vernal, Utah, caught a 25-pound Colorado pikeminnow in 1937. He reminisced about the fish’s food value. “You can see how you cut steaks off that thing,” he said. “I remember a fish like that really was a harvest, and it produced not just one meal, but quite a few meals for the family.”

The Colorado pikeminnow was the Colorado River’s top predator in the early 1900s and has been known to take anglers’ bait in the form of mice, birds, and even small rabbits, despite that its only “teeth” are found on a bony, circular structure located deep within its throat. This fish also readily strikes lures and live bait used to catch sport fish or nonnative fish.

Status and distribution

Listed as endangered by U.S. Fish and Wildlife Service in 1967; given full protection under the Endangered Species Act of 1973.
Listed as endangered under Colorado law in 1976; status changed to threatened in 1998.
Protected under Utah law since 1973.

Colorado pikeminnow were once abundant in the main stem of the Colorado River and most of its major tributaries in Colorado, Wyoming, Utah, New Mexico, Arizona, Nevada and California. Today, two wild populations of Colorado pikeminnow are found in the Upper Colorado River Basin – one in the upper Colorado River system and one in the Green River system. The San Juan River Basin Recovery Implementation Program continues to stock Colorado pikeminnow to develop a separate, self-sustaining population.

The Colorado pikeminnow is adapted to warm rivers and requires uninterrupted passage and a hydrologic cycle characterized by large spring peaks of snowmelt runoff and lower, relatively stable base flows.
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Humpback chub (Gila cypha)

The humpback chub is an endangered, native fish of the Colorado River that evolved around 3-5 million years ago. The pronounced hump behind its head gives this fish a striking, unusual appearance. It has an olive-colored back, silver sides, a white belly, small eyes and a long snout that overhangs its jaw. Like the Colorado pikeminnow and bonytail, the humpback chub is a member of the minnow family.

The humpback chub is a relatively small fish by most standards – its maximum size is about 20 inches and 2.5 pounds. By minnow standards it is a big fish, though not like the giant of all minnows – the Colorado pikeminnow. Humpback chub can survive more than 30 years in the wild. It can spawn as young as 2 to 3 years of age during its March through July spawning season.

Although the humpback chub does not have the swimming speed or strength of the Colorado pikeminnow, its body is uniquely formed to help it survive in its whitewater habitat. The hump that gives this fish its name acts as a stabilizer and a hydrodynamic foil that helps it maintain position. The humpback chub uses its large fins to “glide” through slow-moving areas, feeding on insects that become trapped in water pockets.

Status and distribution

Listed as endangered by U.S. Fish and Wildlife Service in 1967; given full protection under the Endangered Species Act of 1973.
Endangered under Colorado law since 1976.
Protected under Utah law since 1973.

Historically, humpback chub inhabited the swift and turbulent waters in canyons of the Colorado River and three of its tributaries: the Green and Yampa rivers in Colorado and Utah, and the Little Colorado River in Arizona. The species was first discovered in 1946. Before that time, few people ventured into these treacherous regions – including fishery biologists.

Today, five self-sustaining populations of humpback chub occur in the Upper Colorado River Basin. Two to three thousand adults can occur in the Black Rocks and Westwater Canyon core population in the Colorado River near the Colorado/Utah border. Several hundred to more than 1,000 adults may occur in the Desolation/Gray Canyon core population in the Green River. Populations in Yampa and Cataract canyons are small, each consisting of up to a few hundred adults.

The largest known population of humpback chub is in the Lower Colorado River (LCR) Basin in the Grand Canyon -- primarily in the LCR and its confluence with the main stem of the Little Colorado River. In 2009, the U.S. Geological Survey announced that this population increased by about 50 percent from 2001 to 2008. The agency estimates that the number of adults is between 6,000 and 10,000, with the most likely number being 7,650 individuals.
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Bonytail (Gila elegans)

The bonytail is the rarest of the endangered, native fish of the Colorado River and is thought to have evolved around 3-5 million years ago. It has large fins and a streamlined body that is pencil-thin near its tail. Its name describes the fish as an elegant swimmer and member of the “chub” group of minnows. The bonytail has a gray or olive-colored back, silver sides, and a white belly.

Bonytail can grow to 22 inches or more and have been known to live up to 50 years. Bonytail are thought to spawn at 2 to 3 years of age during late June and early July. Bonytail eat insects, plankton, and plant matter.

Status and distribution:

Listed as endangered and given full protection under the Endangered Species Act in 1980.
Endangered under Colorado law since 1976.
Protected under Utah law since 1974.

Bonytail were once common in portions of the upper and lower Colorado River basins. In the early 1900s, Chuck Mack of Craig, Colorado, called them “broomtails” because “…you could get a firm grip on their bony tail.” Chuck and other old-timers used to catch these fish in the Upper Colorado River Basin along with Colorado pikeminnow and razorback sucker. Today, the bonytail is among North America’s most endangered fish species. Its distribution and numbers are so low that it is threatened with extinction. No reproducing populations are known in the wild.

Recognizing that fewer bonytail were being seen in the Colorado River and no young, biologists captured 34 adults from Lake Mohave from 1976 to 1988, and 16 from 1988 to 1989. These fish were held in fish hatcheries. The young of these Lake Mojave fish, and the few remaining adults in hatcheries and in the wild, make up the entire known population of bonytail in the world.

Because there were so few bonytail in existence when recovery efforts began, their preferred habitat is still unknown. Their large fins and streamlined body enable bonytail to swim in swift river flows. Through research and monitoring of stocked fish, researchers continue to gain information to help determine this species’ life-history needs and ways to improve their survival.
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Razorback sucker (Xyrauchen texanus)

Three to 5 million years ago, a unique-looking fish with a sharp-edged hump “razorback” behind its head swam the Colorado River and its tributaries. The razorback sucker is an endangered, native fish of the Colorado River and the only member of the genus Xyrauchen. It has a dark, brownish-green upper body with a yellow to white-colored belly and an abrupt, bony hump on its back shaped like an upside-down boat keel.

One of the largest suckers in North America, the razorback sucker can grow to 3 feet in length and can live for more than 40 years. Razorback sucker can reproduce at 3 to 4 years of age. Depending on water temperature, spawning can occur as early as November or as late as June. In the Upper Colorado River Basin razorback sucker typically spawn between mid-April and mid-June. Razorback sucker eat insects, plankton, and plant matter on the bottom of the river.

To complete its life cycle, the razorback sucker moves between adult, spawning, and nursery habitats. Spawning occurs during high spring flows when razorback sucker migrate to cobble bars to lay their eggs. Larvae drift from the spawning areas and enter backwaters or floodplain wetlands that provide a nursery environment with quiet, warm, and shallow water.

Research shows that young razorback sucker can remain in floodplain wetlands where they grow to adult size. As they mature, razorback sucker leave the wetlands in search of deep eddies and backwaters where they remain relatively sedentary, staying mostly in quiet water near the shore.
In the spring, razorback sucker return to the spawning bar, often quite a long distance away, to begin the life cycle again.

Status and distribution

Listed as endangered and given full protection under the Endangered Species Act in 1991.
Endangered under Colorado law since 1979.
Protected under Utah law since 1973

Historically, the razorback sucker was widespread and abundant in the Colorado River and its tributaries.
Tom Hastings of Green River, Utah, recalled a trapper with a penchant for razorback suckers.“There was an old trapper here, well he was here after I come back from World War II,” Hastings said. “He’d catch those suckers and eat them. I don’t know how they fixed them, but they thought they were better than catfish.”

Today all populations of razorback sucker are supplemented with stocked fish except for the Lake Mead population. Lakes Mead and Mohave are the only population with wild fish.