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ESAblawg is an educational effort by Keith W. Rizzardi. Correspondence with this site does not create a lawyer-client relationship. Photos or links may be copyrighted (but used with permission, or as fair use). ESA blawg is published with a Creative Commons License.

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florida gators... never threatened!

If you ain't a Gator, you should be! Alligators (and endangered crocs) are important indicator species atop their food chains, with sensitivity to pollution and pesticides akin to humans. See ESA blawg. Gator blood could be our pharmaceutical future, too. See ESA musing.


Follow the truth.

"This institution will be based on the illimitable freedom of the human mind. For here we are not afraid to follow truth wherever it may lead, nor to tolerate any error so long as reason is left free to combat it." -- Thomas Jefferson to William Roscoe, December 27, 1820.


Thanks, Kevin.

KEVIN S. PETTITT helped found this blawg. A D.C.-based IT consultant specializing in Lotus Notes & Domino, he also maintains Lotus Guru blog.

« FWS notices status review of 23 southeastern species | Main| FWS proposes listing of five foreign bird species, including Ecuador's Esmeraldas woodstar »

FWS says listing of roundtail chub DPS warranted but precluded

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74 Fed. Reg. 32352 / Vol. 74, No. 128 / Tuesday, July 7, 2009 / Proposed Rules
DEPARTMENT OF THE INTERIOR / Fish and Wildlife Service / 50 CFR Part 17 / Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List a Distinct Population Segment of the Roundtail Chub (Gila robusta) in the Lower Colorado River Basin

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 12-month finding on a petition to list a distinct population segment (DPS) of the roundtail chub (Gila robusta) in the lower Colorado River basin as endangered or threatened under the Endangered Species Act of 1973, as amended (Act). The petition (by CBD)also asked the Service to designate critical habitat. After review of all available scientific and commercial information, we find that the petitioned listing action is warranted, but precluded by higher priority actions to amend the Lists of Endangered and Threatened Wildlife and Plants. Upon publication of this 12- month petition finding, this species will be added to our candidate species list. We will develop a proposed rule to list this population segment of the roundtail chub pursuant to our Listing Priority System. Any determinations on critical habitat will be made at that time.  SEE ALSO, prior ESA blawg

Roundtail chubs,  in the lower Colorado River basin (as pictured above from Bureau of Reclamation) are found in cool to warm waters of rivers and streams, and often occupy the deepest pools and eddies of large streams.  They are omnivores, but algae and aquatic insects can be major portions of the diet.  
EXCERPT RE: DPS CONCLUSION: We have reevaluated the lower Colorado River populations of the roundtail chub to determine whether they meet the definition of a DPS, addressing discreteness and significance as required by our policy. We have considered the extent of the range of the roundtail chub in the lower Colorado River basin relative to the rest of the species’ range, the ecological setting of roundtail chub in the lower Colorado River basin, and available information on the genetics of the species. We conclude that the lower Colorado River populations are discrete from the upper Colorado River basin populations on the basis of their present and historical geographic separation of 275 river mi (444 km) and because few historical records have been detected in the mainstem Colorado River between the two population centers that would confirm significant connectivity historically. We also conclude that the lower Colorado River basin roundtail chub is significant because of its unique ecological setting compared to the upper basin, and because the loss of the species from the lower basin would result in a significant gap in the range of the species. Genetic information for this species has long been difficult to interpret, and additional data and analysis may help to clarify this.

EXCERPT RE: THREATS ANALYSIS:  Threats, including water diversions, groundwater pumping, dams, channelization, and erosion-related effects, are occurring that impact both the amount of water available for habitat, as well as the water’s suitability for roundtail chub.  Threats from flood control, development, roads, water withdrawal, improper livestock grazing, recreation, and high-intensity wildfire dry up, silt in, physically alter, and chemically pollute habitats of the roundtail chub such that habitats become permanently unsuitable...  All of these threats are anthropogenic and can be expected to continue, if not increase, given the predictions for increases in human population expansion in the region...  Predation and competition with nonnative aquatic species, and in particular fish, are, along with dewatering of habitat, the most significant threats to the roundtail chub in the lower Colorado River basin.

EXCERPT RE: CLIMATE CHANGE: If predicted effects of climate change result in persistent drought conditions in the Colorado River basin similar or worse than those seen in recent years, water resources will become increasingly taxed as supplies dwindle and demand stays the same or increases. Likewise, there would be increased demand on surface and groundwater supplies in Arizona. Clearly, permanent water is crucial for the continued survival of native fish in the region, including roundtail chub. Essentially the entire range of the roundtail chub in the lower Colorado River basin is predicted to be at risk of becoming more arid (Seager et al. 2007, pp. 1183–1184), which has severe implications to the integrity of aquatic and riparian ecosystems and the water that supports them. Perennial streams in the region may become intermittent and streams that are currently intermittent may become unsuitable or dry completely.