WHY ARE THEY ENDANGERED?

Water Development

Human population growth has created a big need for water and hydro electrical power in western states. Hundreds of water projects (dams, canals, irrigation projects) have been built in the Colorado River, blocking some migration routes of the Colorado pikeminnow and other species. Waters are 15 degrees now colder than the rare fishes’ preferred habitat.

Wetlands

The number and size of life-supporting wetlands has been cut dramatically across the United States. Over the last 200 years, Colorado has lost about half of its wetlands. Young native fish needed these areas to grow faster and it gave them warmer, slower-moving water full of food.

Non-Native Fish

Historically, there were only 14 fish species in the upper Colorado River Basin. Then people began putting non-native fish into lakes, reservoirs, and streams in the Colorado River. Now the endangered fish have to compete with more than 40 non-native species. These non-native species (such as northern pike, channel catfish, red shiner and fathead minnow) are also hunters that prey on the eggs and young of the endangered fish.

Selenium

Part of the upper Colorado River basin have high levels of a chemical called selenium. Animals need this naturally occurring chemical in certain amounts, but in larger amounts, selenium can cause birth defects in the wildlife.

Anglers

Angling is a fishing style by using an angled hook. The aglers that use this method of fishing want to catch non-native fish and after hooking a native fish, the angler did not release the fish properly. The anger may have tossed it on the riverbank to die

Other Factors

Other factors that affect the endagered animals are pollution, parasite, and hybrization.