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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.

Slenderclaw crayfish listing proposal, 4(d) Rule, Critical Habitat

What action is being proposed by the U.S. Fish and Wildlife Service?

As a result of the completion of a Species Status Assessment (SSA) and 12-month finding, the Service is proposing to list the slenderclaw crayfish as threatened under the Endangered Species Act (ESA) with a 4(d) rule and designate critical habitat. An SSA is an in-depth review of the species’ biology and threats, an evaluation of its biological status, and an assessment of the resources and conditions needed to maintain long-term viability. Learn more about Species Status Assessments.

Why is the slenderclaw crayfish threatened?

Threats, including reduced connectivity due to reservoirs and dams, have hindered the crayfish’s ability to move throughout its range. More importantly, the primary threat is an invasive species called the virile crayfish found within the Short Creek population boundary of the slenderclaw crayfish. If the virile crayfish invades the slenderclaw’s current locations in Shoal Creek, the slenderclaw population could potentially be wiped out of the one of only two populations of the species.

What is the slenderclaw crayfish’s historic range and where can I find it now?

The historical range of the slenderclaw crayfish included four small streams or tributaries within the two watersheds. Historically, it was known to be in five sites: one site in Short Creek, one site in Shoal Creek, two sites in Scarham Creek, and one in Bengis Creek.

Currently, the slenderclaw crayfish is in five sites within two populations: Three sites in Shoal Creek and two sites in the Town Creek watershed (one in Bengis Creek and one in Town Creek). The site on Short Creek where it is no longer found is now occupied by the non-native virile crayfish, which has been identified as the primary future threat to the slenderclaw crayfish.

What is a 4(d) rule?

For a threatened species, the Service may use flexibility provided under the ESA’s Section 4(d) to tailor the take prohibitions to those that provide conservation benefits for the species; referred to as a 4(d) rule. The ESA allows for 4(d) rules that are “necessary and advisable” for the conservation of the species. This targeted approach can reduce ESA conflicts by allowing some activities to continue that may benefit the crayfish and do not significantly harm it, while focusing our efforts on the threats that slow species recovery. These customized protections of the ESA minimize the regulatory burden while maximizing the likelihood of recovery of a threatened plant/animal.

How does the 4(d) rule affect activities that occur in slenderclaw crayfish habitat?

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 incorporate management of invasive crayfish into the 4(d) rule and will be requesting comments on this specifically.

What is critical habitat?

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. It does not set up a preserve or refuge, but it may require special management considerations in the identified areas. Designating critical habitat under the ESA does not affect private landowners unless the action involves federal funds, permits or other federal activities. The final decision to designate critical habitat will be based on the best scientific information available.

What are the proposed critical habitat units for the slenderclaw crayfish?

The proposed critical habitat designation for the slenderclaw crayfish consists of 52 river miles 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, which are publicly owned by the state and counties. Unit 1 includes stream habitat in Bengis and Town creeks. Unit 2 includes stream habitat in Shoal, Scarham and Short creeks.

Why did the Service select these units?

The slenderclaw crayfish occurs in small to medium flowing streams with intact native vegetation on the stream banks and boulder and cobble substrates. In addition, the species needs abundant space within each habitat type for sheltering and adequate seasonal water flows to maintain connectivity of streams.

How can I comment on this proposal?

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 complete listing proposal can be obtained by visiting the Federal eRulemaking Portal: at Docket Number FWS–R4–ES–2018-0069. A copy can also be obtained by contacting U.S. Fish and Wildlife Service, 1208-B Main Street, Daphne, Alabama, 36526.

Written comments and information may be submitted:

  1. online at by entering FWS-R4-ES-2018-0069 in the search box and then clicking on “Comment Now”; or
  2. mail or hand deliver to U.S. Fish and Wildlife Service, Public Comments Processing, Attn: FWS-R4-ES-2017-0063; 4500030113, U.S. Fish and Wildlife Headquarters, MS: BPHC, 5275 Leesburg Pike, Falls Church, VA 22041-3803. All comments must be received on or before December 10, 2018. Requests for a public hearing must be made in writing within 45 days by November 23, 2018, to the Falls Church, VA, address.

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