Humpback Chub In Colorado To Be Protected By Chemical Warfare Against Small Mouth Bass

The humpback chub is an endangered species of fish in Colorado. The National Park Service (NPS) intends to deploy a chemical agent to kill two of its enemies. Invasive small mouth bass and green sunfish. The targeted kill is designed to keep the predators out of the humpback chub’s region.

A humpbacked chub (Gila cypha). Protection is apparently leading to the chub’s comeback. That may be threatened by small mouth bass and other fish predators .

To protect the humpback chub the NPS will use rotenone, a chemical agent that is deadly to the target fish but approved for use in the waterways, according to the Washington Post

According to Science Direct rotenone has been used for centuries:

“Rotenone is a naturally occurring compound extracted from the roots, leaves, and seeds of plants in the pea family and used for centuries by native Indians as a tool for hunting fish in rivers and streams.”

According to NPS rotenone is a potent natural insecticide. It disrupts the energy cycle at cellular levels. The lack of usable energy results in death.

Small-Mouthed Black Bass( Micropterus Dolomieu) illustrated by Sherman F. Denton (1856-1937) from Game Birds and Fishes of North America. Digitally enhanced from our own 1913 Portfolio Edition of the book.
Small mouth bass are aggressive predators and threaten the chub. They are popular with anglers as they are good eating.

Green sunfish(leopomis cyanellus) are small but highly predatory fish. Smallmouth bass (Microperus dolomieu) are another predatory fish. Both are popular with anglers and those who love a pan-fried fish dinner. Environmentalists, state biologists and ecologists are less thrilled. The two species are expanding their range at the expense of other fish – some endangered.

The humpback chub could be wiped out by the two fish. Because the two predators are good eating increased human consumption is seen as part of the solution.

According to the US Fish and Wildlife Service:

“The humpback chub is a native species of the Colorado River that evolved around 3.5 million years ago and is only found in warm-water canyons of the Colorado River basin. The humpback chub was first described from a fish caught in 1933 near Bright Angel Creek, a tributary of the Colorado River in Grand Canyon, making it one of the last large fish species to be described in North America. The species was protected under the Endangered Species Act in 1973 because large dams and human water use changed the river flow. Actions to conserve the humpback chub include managing river flows, providing passage around dams, and removing non-native predators. Monitoring of humpback chub populations indicates that management actions are benefiting the species. In fact, the Little Colorado River population in Grand Canyon is now estimated at more than 11,000 fish, and the Westwater Canyon population in Utah is estimated to exceed 3,300 fish.”

Northern snakeheads are both an aggressive invasive species and food for a family meal

The Fish and Wildlife Service feels keeping the predators our of the canyons of the Colorado River Basin is imperative. Invasive northern snakeheads are another invasive threat to native fish. Authorities ask anglers to freeze them to death or toss them on the grill.


Published by ursusrising

long time writer and editor living in Los Angeles

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