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| Photo Credit: AP. |
A predatory invasive fish species has been sighted in lower Colorado River as it makes a comeback which could inevitably threaten native fish populations. National Park Service fisheries biologist Jeff Arnold spotted three young fish in a shallow backwater of the lower Colorado River last week that didn’t belong there
“Give me a call when you get this!” he
messaged a colleague, snapping photos, The Associated Press reported.
The
Associated Press reported that the park service confirmed their worst fear:
smallmouth bass had in fact been found and were likely reproducing in the
Colorado River below Glen Canyon Dam.
Smallmouth
bass feast on humpback chub, an ancient, threatened fish that is native to the
river, according to The Associated Press. Arnold and other biologists have been
working hard to recover the clear the threat and send them to their native
water.
The
predators wreaked havoc in the upper river, but were held at bay in Lake Powell
where Glen Canyon Dam has served as barrier for years. But it appears the fish
has found a way out of its restraint. The reservoir’s recent sharp decline is
enabling these introduced fish to get past the dam and closer to where the
biggest population of chub remain, farther downstream in the Grand Canyon, The
Associated Press reports.
Brian Healy
has worked with the humpback chub for more than a decade and founded the Native
Fish Ecology and Conservation Program, The Associated Press reports.
“It’s pretty
devastating to see all the hard work and effort you’ve put into removing other
invasive species and translocating populations around to protect the fish and
to see all that effort overturned really quickly,” Healy said.
Nonnative
fish that live in warm surface waters in Lake Powell are moving closer to the dam
and its penstocks as reservoir levels drop. The fish finds its way through
submerged steel tubes that carry water to turbines and are released on the
other side.
The implication
of this movement is that Smallmouth bass could reproduce below the dam and
reach population levels that could seriously attack and threaten chub and other
natives.
The chub has
just survived possible extinction but things turned around following the work
of fish biologists and engineers. Agencies are spending millions of dollars
annually to keep intruders in check in the upper portion of the river,
according to The Associated Press.