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A crayfish with brown and white splotches and narrow claws with deep red tips
Information icon Slenderclaw crayfish (Cambarus cracens). Photo © Guenter Schuster.

Service proposes to list rare freshwater crayfish, designate Critical Habitat

The U.S. Fish and Wildlife Service is proposing to list the slenderclaw crayfish as threatened under the Endangered Species Act (ESA). At the same time, it also is proposing to designate critical habitat and a 4(d) rule describing management activities that would continue to be permitted because of the benefit to the crayfish and landowners.

With two known populations, the slenderclaw crayfish is disappearing throughout its range. Historically, the crayfish was known to live in four small streams or tributaries within the Short Creek and Town Creek watersheds, both in the Tennessee River Basin in Dekalb and Marshall counties, Alabama. Today, the population has dwindled to three streams within the Short Creek and Town Creek watersheds. These streams are found in tributaries of Guntersville Lake, a popular recreational spot in northeastern Alabama.

Several factors may be contributing to the decline of the slenderclaw crayfish. Currently, the primary threat is an invasive species called the virile crayfish, a larger, non-native crayfish, and a fierce competitor of the slenderclaw crayfish. The migrating virile crayfish has been documented in the slenderclaw’s historic range.

The slenderclaw crayfish is recognized as a Priority 1/Highest Conservation Priority by Alabama, meaning the state has been actively engaged with local and federal partners in understanding and addressing threats to the crayfish and other imperiled wildlife that share its habitat. There are currently many programs in place to help improve the slenderclaw’s habitat including the Natural Resources Conservation Service’s (NRCS) National Water Quality Initiative and the Farm Service Agency’s (FSA) Conservation Reserve Program. Both agencies are part of the U.S. Department of Agriculture.

4(d) Rule

A 4(d) rule is a targeted approach under the ESA that allows some activities to continue that do not significantly harm the species. This proposed 4(d) rule would allow flexibility for bank stabilization projects that do not use heavy equipment in streams. In addition, the Service is considering how to apply reintroduction efforts into the 4(d) rule and NRCS and FSA projects with willing private landowners. In addition, the Service is considering how to incorporate management of invasive crayfish into the 4(d) rule and requests comments on this specifically.

Critical Habitat

The proposed critical habitat designation for the slenderclaw crayfish consists of 52 river miles of occupied habitat and 26 river miles of habitat unoccupied by the crayfish, totaling 78 river miles. The two proposed units are privately owned except for the bridge crossings and road easements that are publicly owned by the state and counties.

The designation of critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve or other conservation area. A critical habitat designation identifies areas that are important to the conservation of federally listed threatened or endangered species. This designation does not allow the government or public to access private lands, nor does it require implementation of restoration, recovery or enhancement measures by non-federal landowners.

Proposed Unit 1 includes stream habitat in Bengis and Town creeks. Proposed Unit 2 includes stream habitat in Shoal, Scarham and Short creeks. Establishing critical habitat will raise awareness of the needs of the slenderclaw crayfish and other imperiled species and focus the efforts of our conservation partners. It also alerts federal agencies that they are required to make special conservation efforts when they work, fund or permit activities in those areas.

The public is invited to submit written comments on the proposal to list the slenderclaw crayfish with a 4(d) rule, and designate critical habitat up to 60 days from its October 9, 2018 publication in the Federal Register. Please submit comments by December 10, 2018. The Service will post all comments on This generally means the agency will post any personal information provided through the process.

All relevant information received during the open comment period from the public, government agencies, the scientific community, industry, or any other interested parties will be considered and addressed in the Service’s final listing determination and critical habitat designation for the slenderclaw crayfish.

The complete listing proposal can be obtained by visiting the Federal eRulemaking Portal: at Docket Number FWS–R4–ES–2018-0069.

Download the Species Status Assessment (SSA), or learn more about this decision by reading the frequently asked questions.


The mission of the U.S. Fish and Wildlife Service is working with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. For more information on our work and the people who can make it happen, visit Connect with the Service on Facebook, follow our tweets, watch the YouTube Channel and download photos from Flickr.

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