Plans by the Trump administration to downlist the humpback chub in the Colorado River from endangered to threatened are drawing protests/Arizona Game and Fish Department
A plan by the Trump administration to reclassify the humpback chub from "endangered" to "threatened" in the Colorado River has drawn concern from a conservation group that maintains the plight of the fish has gotten worse, not improved.
The fish, which is found only in Colorado, Utah and Arizona, faces severe threats from drought related to climate change and overuse of water, as well as from invasive species like smallmouth bass, says the Center for Biological Diversity.
“The humpback chub remains very much endangered,” said Taylor McKinnon at the Center for Biological Diversity. “One of the six remaining populations was recently lost, and the remaining fish face multiple threats, from climate change to new dams. This is a disturbing attack on an endangered species by the Trump administration, which has been systematically removing protections from our waters and wildlife.”
When the recovery plan was last revised by the U.S. Fish and Wildlife Service in 2002, the humpback chub had six populations, five in the upper Colorado Basin and one in the lower Colorado Basin. One of the populations, found in Dinosaur National Monument, has since died out, according to the Center.
The other upper basin populations declined in the early 2000s, but have since stabilized at lower population sizes that are considered below the minimum viability requirements established by the plan. Only the lower basin population meets such criteria, but it is found primarily in the Little Colorado River, which is now threatened by two proposed dams that would harm or destroy all of the fish’s critical habitat there.
All of the populations are dependent on ongoing management such as hatchery stocking and non-native fish removal.
“Humpback chub are hanging on by a thread, but somehow the Trump administration is arguing they’ve recovered, which makes no sense,” McKinnon said.
None of the projections in the downlisting rule foresees a bright future for the fish. Its survival is highly dependent on voluntary management actions that may or may not be successful. As with other recent species-protection decisions, the Trump administration downplayed the effects of climate change by only looking 40 years into the future, despite the fact that climate models extend to 2100 and paint a grim picture of water availability in the Colorado River.
“These fish will fall victim to the Trump administration’s determination to ignore climate change’s huge threats if we don’t immediately get emissions under control,” McKinnon said. “Climate change is drying the Colorado River. This is the wrong time to reduce protections for fish like the humpback chub.”
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Comments
Climate change is the culprit? How?
Smallmouth bass is an invasive species? Since when? Smallmouth bass has lived inthe river forever. How does a dam effect the species...they don't spawn.
Why don't those who are concerned raise the species and release in the river to maintain the species?
Pappytx--
working backward:
As noted in the article, humpback chub _are_ being raised in hatcheries and relesed into the river in attempts to sustain some populations.
Dams affect humpback chub primarily by converting the river from warmer brown silty water to much colder clear water from the bottoms of the reservoirs. Dam (hydroelectric) operations also affect the fish and their habitat by nearly eliminating both sustained May - June high snowmenlt flows and very low winter flows. A very effective visualization of the changes is at https://www.goldensoftware.com/success-stories/visualizing-water-flow-pa... [I do not use their software and I do not recommend it (5 lines of R code could recreate that figure), but it's an awesome visualization of the changes by the person who first used heatmaps by year and day of year.]
Smallmouth bass are not native to any of the Colorado River basin. See https://littleriveroutfitters.com/pages/fishing/smallmouth-distribution.... one source of their native range. While they are not native, smallmouth bass may or may not qualify as an "invasve species" depending on your definition, as they spread among river systems via deliberate transport and stocking.
That all said, climate change is a modest culprit. The Colorado River flow has been over-allocated for decades; the river already has 3 large dams, and the Green River below Flaming Gorge was rotenoned to kill native fish when Flaming Gorge was put in circa 1960. Climate change reducing the average annual discharge and increasing the frequency of prolonged droughts interacts with the human population boom in Arizona, Southern Utah, and Southern California, to push for additional dams and even less water discharge for "envionmental" reasons such as the native fish or even the sandbars and riaprian ecosystem in the Grand Canyon,as noted in the last paragraph of this article.