2010-7849. Approved Recovery Plan for the Scaleshell Mussel

AGENCY:

Fish and Wildlife Service, Interior.

ACTION:

Notice of document availability.

SUMMARY:

We, the U.S. Fish and Wildlife Service (Service), announce the availability of the approved recovery plan for the scaleshell mussel (Leptodea leptodon). The endangered scaleshell mussel is now consistently found in only the Meramec, Bourbeuse, and Gasconade Rivers in Missouri. This plan includes specific recovery objectives and criteria to achieve removal of the species from the protections of the Endangered Species Act (Act).

ADDRESSES:

You may obtain a copy of the recovery plan by sending a request to Field Supervisor, U.S. Fish and Wildlife Service, Ecological Services Field Office, 101 Park DeVille Drive, Suite A, Columbia, MO 65203 (printed copies will be available for distribution within 4 to 6 weeks), or by downloading it from the Internet at: http://www.fws.gov/​endangered/​recovery/​index.html#plans.

FOR FURTHER INFORMATION CONTACT:

Mr. Andy Roberts, by telephone at [phone] ext. 110. TTY users may contact Mr. Roberts through the Federal Relay Service at [phone].

SUPPLEMENTARY INFORMATION:

Background

Recovery of endangered or threatened animals and plants to the point where they are again secure, self-sustaining members of their ecosystems is a primary goal of the Service's endangered species program. To help guide the recovery effort, we are working to prepare recovery plans for most listed species native to the United States. Recovery plans describe actions considered necessary for the conservation of the species, establish criteria for reclassification or delisting listed species, and estimate time and cost for implementing the measures needed.

The Act (16 U.S.C. 1531 et seq.) requires us to develop recovery plans for listed species unless such a plan will not promote the conservation of a particular species. Section 4(f) of the Act, as amended in 1988, requires us to provide the public notice, and an opportunity for public review and comment, during recovery plan development. We provided the draft scaleshell recovery plan to the public and solicited comments from August 6, 2004, through September 7, 2004 (69 FR 47949). We considered information we received during the public comment period, and information from peer reviewers, in our preparation of the recovery plan, and also summarized that information in Appendix V of this approved recovery plan.

We listed the scaleshell as endangered on October 9, 2001 (66 FR 51322). The current distribution of the scaleshell is limited to only three rivers in Missouri: the Meramec, Bourbeuse, and Gasconade. Surveys indicate that the species is in decline throughout these areas. In the last 25 years, it has been reported from 15 additional streams in Arkansas, Oklahoma, and South Dakota, but only has been represented by a small number or a single specimen (live or dead) collected during one or more extensive mussel surveys of these rivers.

The scaleshell occurs in medium-to-large rivers with low-to-medium gradients. It primarily inhabits stable riffles and runs with gravel or mud substrate and moderate current velocity. The scaleshell requires good water quality, and is usually found where a diversity of other mussel species are concentrated. More specific habitat requirements of the scaleshell are unknown, particularly of the juvenile stage. Water quality degradation, sedimentation, channel destabilization, and habitat destruction are contributing to the decline of the scaleshell throughout its range. The spread of the nonnative zebra mussel (Dreissena polymorpha) may threaten scaleshell populations in the near future.

The scaleshell must complete a parasitic phase on freshwater drum (Aplodinotus grunniens) to complete its life cycle. The scaleshell's complex life cycle and extreme rarity hinders its ability to reproduce. The sedentary nature of the species and the low density of remaining populations exacerbate threats to its survival posed by the natural and manmade factors. Further, the relatively short life span of the scaleshell may render it less able to tolerate periods of poor recruitment. The remaining populations are very susceptible to local extirpation, with little chance of recolonization because of their scattered and isolated distribution.

The principal recovery strategy is to conserve existing habitat and restore degraded habitat by addressing threats immediately adjacent to occupied sites and in upstream areas of occupied watersheds. Stream reaches occupied by the scaleshell have numerous and widespread threats affecting the species. In some cases, these threats are related to the surrounding land use and can originate upstream of extant populations. Therefore, some recovery actions may need to be implemented on a large scale in order to restore aquatic habitat downstream. Other recovery actions include artificial propagation to increase and stabilize populations, and research on the biology, ecology, and genetics of the species.

Recovery efforts on this scale will not be possible without soliciting outside help to restore aquatic habitat and improve surface lands. The assistance of Federal and State agencies, conservation groups, local governments, private landowners, industries, businesses, and farming communities will be essential in implementing the necessary recovery actions for the scaleshell to meet recovery goals. The role of private landowners, nonprofit organizations, and corporations cannot be overemphasized, as most land in watersheds occupied by the scaleshell is under private ownership.

The scaleshell mussel will be considered for delisting when section 4(a)(1) threat factors under the Act are assessed and when the following criteria are met:

(1) Through protection of existing populations, successful establishment of reintroduced populations, or the discovery of additional populations, a total of eight stream populations exist, each in a separate watershed and each made up of at least four local and geographically distinct populations with, at a minimum, one stream population located in the Upper Mississippi River Basin, four in the Middle Mississippi River Basin (two of these must exist east of the Mississippi River), and three in the Lower Mississippi River Basin;

(2) Each local population in Criterion 1 is viable in terms of population size, age structure, recruitment, and persistence; and

(3) Threats to local populations in Criterion 1 have been identified and addressed per measurable criteria developed in the Recovery Plan.

We will achieve these criteria through the following actions:

(1) Stabilizing existing populations through artificial propagation to prevent extirpation;

(2) Formation of partnerships and utilization of existing programs to protect remaining populations, restore habitat, and improve surface lands;

(3) Improving understanding of the biology and ecology of the scaleshell;

(4) Further delineating the current status and distribution of the scaleshell;

(5) Restoring degraded habitat in areas of historical range;

(6) Reintroducing the scaleshell into portions of its former range;

(7) Initiating various educational and public outreach actions to heighten awareness of the scaleshell as an endangered species and to solicit help with recovery actions; and

(8) Tracking recovery and conducting periodic evaluations with respect to recovery criteria.

Criteria are also provided in the recovery plan to reclassify the scaleshell mussel to threatened status. The species will be considered for reclassification when section 4(a)(1) threat factors under the Act are assessed and when either of the following criteria is met:

(1) Through protection of existing populations, successful establishment of reintroduced populations, or the discovery of additional populations, four stream populations exist, each in a separate watershed and each made up of at least four local populations located in distinct portions of the stream;

(2) Each local population in Criterion 1 is viable in terms of population size, age structure, recruitment, and persistence; and

(3) Threats to local populations in Criterion 1 have been identified and addressed per the measurable criteria developed in the Recovery Plan.

Authority: Sec. 4(f) of the Endangered Species Act, 16 U.S.C. 1533(f).

Dated: March 18, 2010.

Lynn M. Lewis,

Assistant Regional Director, Ecological Services, Midwest Region.