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.” (Also see: Historical perspective.)

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.

Working to recover the species

Actions being taken to recover the Colorado pikeminnow include:

  • Managing water to provide adequate instream flows to create beneficial water flow
  • Constructing fish passages and screens at major diversion dams to provide endangered fish with access to hundreds of miles of critical habitat
  • Developing backwaters for early life stages
  • Monitoring fish population numbers
  • Managing nonnative fishes

Recovery goals

Colorado pikeminnow will be considered eligible for downlisting from “endangered” to “threatened” and for removal from Endangered Species Act protection (delisting) when all of the following conditions are met:

  • Self-sustaining fish populations reach the required numbers in areas of the Green, Colorado and/or San Juan rivers as identified in the chart below.
  • The threat of significant “fragmentation” of the population has been removed. (Fragmentation refers to separation between fish populations caused by geographical distance or physical barriers.)
  • Essential habitats, including primary migration routes and required stream flows are legally protected.
  • Other identifiable threats that could significantly affect the population are removed.

DEMOGRAPHIC CRITERIA FOR RECOVERY
DOWNLISTINGDELISTING
COLORADO PIKEMINNOW
Over a 5-year monitoring period:
  • Maintain the upper basin metapopulation*
  • Maintain populations in Green River and upper Colorado River subbasins (“no net loss”)
  • Green River subbasin population > 2,600 adults
  • Upper Colorado River subbasin population > 700 adults
  • Establish 1,000 age-5+ subadults in San Juan River
For 7 years beyond downlisting:
  • Maintain the upper basin metapopulation*
  • Maintain populations in Green River
    and upper Colorado River subbasins (“no net loss”)
  • Green River subbasin
    population > 2,600 adults
  • Upper Colorado River subbasin
    population > 1,000 adults OR
    Upper Colorado River subbasin population > 700 adults and San Juan River population > 800 adults
*A metapopulation consists of a group of spatially separated populations of the same species which interact at some level, or "a population of populations."

Sacramento pikeminnow, Umpqua pikeminnow and northern or Columbia River pikeminnow

In addition to the Colorado pikeminnow, there are three other species of pikeminnow in the United States: the Sacramento pikeminnow, Umpqua pikeminnow and northern or Columbia River pikeminnow. Each of these is a different species of pikeminnow, much like a cutthroat trout and rainbow trout are different species of trout or a grizzly and black bear are different species of bear.

None of these other species has been known to grow to the size of the Colorado pikeminnow. Also, each species of pikeminnow has a distinct appearance and behavior. For example, the northern pikeminnow originally evolved in lakes and appears to adapt easily to reservoirs.

Unlike the endangered Colorado pikeminnow, northern pikeminnow are able to thrive despite habitat alterations resulting from the installation of dams and introductions of nonnative fish species.

The northern pikeminnow also preys effectively on sport fish, and often becomes the dominant species in reservoirs, despite biologists’ efforts to limit their population size. Northern pikeminnow are so prevalent in the Columbia River Basin that they are considered a threat to salmon species.