Daily Rules, Proposed Rules, and Notices of the Federal Government


Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-ES-R4-2012-0031; 4500030113]

RIN 1018-AX73

Endangered and Threatened Wildlife and Plants; Proposed Endangered Status for the Neosho Mucket, Threatened Status for the Rabbitsfoot, and Designation of Critical Habitat for Both Species

AGENCY: Fish and Wildlife Service, Interior.
ACTION: Proposed rule.
SUMMARY: We, the U.S. Fish and Wildlife Service, propose to list the Neosho mucket (Lampsilis rafinesqueana), a freshwater mussel, as endangered and rabbitsfoot (Quadrula cylindrica cylindrica), a freshwater mussel, as threatened under the Endangered Species Act; and propose to designate critical habitat for both species. This rule fulfills our obligation under a settlement agreement. The effect of this regulation is to conserve the Neosho mucket and rabbitsfoot and their habitats under the Endangered Species Act.
DATES: We will accept comments received or postmarked on or before December 17, 2012. Comments submitted electronically using the Federal eRulemaking Portal (seeADDRESSESsection, below) must be received by 11:59 p.m. Eastern Time on the closing date. We must receive requests for public hearings, in writing, at the address shown in theADDRESSESsection by November 30, 2012.
ADDRESSES: (1)Electronically:Go to the Federal eRulemaking Portal: the Keyword box, enter Docket No. FWS-R4-ES-2012-0031, which is the docket number for this rulemaking. Then, in the Search panel on the left side of the screen, under the Document Type heading, click on the Proposed Rules link to locate this document. You may submit a comment by clicking on "Send a Comment or Submission."

(2)By hard copy:Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS-R4-ES-2012-0031; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.

We request that you send comments only by the methods described above. We will post all comments on generally means that we will post any personal information you provide us (see the Public Comments section below for more information).

FOR FURTHER INFORMATION CONTACT: James F. Boggs, Field Supervisor, U.S. Fish and Wildlife Service, Arkansas Ecological Services Office, 110 South Amity Road, Suite 300, Conway, AR 72032, by telephone 501-513-4470 or by facsimile 501-513-4480. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800-877-8339.

This document consists of: (1) A proposed rule to list the Neosho mucket (Lampsilis rafinesqueana) as endangered and rabbitsfoot (Quadrula cylindrica cylindrica)as threatened; and (2) a proposed critical habitat designation for both species.

Executive Summary

Why we need to publish a rule.Under the Endangered Species Act (Act), a species may warrant protection through listing if it is endangered or threatened throughout all or a significant portion of its range. The Neosho mucket and rabbitsfoot are highly restricted in their ranges and the threats occur throughout their ranges; therefore, the species qualify for listing. We are proposing to list the Neosho mucket as an endangered species and rabbitsfoot as a threatened species. Their protection under the Act can only be done by issuing a rule.

• We estimate the Neosho mucket has been extirpated (no longer in existence) from approximately 62 percent of its historical range with only 9 of the 16 historical populations remaining (extant). This mussel is declining rangewide (eight of the nine extant populations) with only one remaining large viable population.

• We estimate the rabbitsfoot has been extirpated from approximately 64 percent of its historical range. While 51 of the 140 historical populations are extant (remain), only 11 populations (22 percent of extant populations or 8 percent of the historical populations) are viable; 23 populations (45 percent of extant populations) are at risk of extirpation; and 17 populations (33 percent of extant populations) show limited recruitment with little evidence of sustainability. Rabbitsfoot is extirpated from 2 States within its historical range.

• The majority (8 of the 11 or 73 percent) of the viable rabbitsfoot populations live in waters considered impaired under section 303(d) of the Clean Water Act or have numerous tributaries in their watersheds also listed as impaired. Thus, these mussels are subjected to water quality and quantity and sediment quality constraints. These constraints (impairment) are expected to be exacerbated by increased water demand, habitat degradation, and climate change. Therefore, the viability of the majority of rabbitsfoot populations is uncertain.

• The majority of extant rabbitsfoot populations are marginal to small (40 of 51 extant populations (78 percent)) and isolated (41 of 51 extant populations (80 percent)); because of the isolation, it is unlikely that recruitment between populations or establishment of new populations could occur naturally.

• We are proposing to list the Neosho mucket as an endangered species in Arkansas, Kansas, Missouri, and Oklahoma and the rabbitsfoot as a threatened species in Alabama, Arkansas, Georgia, Kansas, Kentucky, Illinois, Indiana, Louisiana, Mississippi, Missouri, Ohio, Oklahoma, Pennsylvania, Tennessee, and West Virginia.

The basis for our action.Under the Endangered Species Act, a species may be determined to be endangered or threatened based on any of five factors: (1) Destruction, modification, or curtailment of its habitat or range; (2) overuse; (3) disease or predation; (4) inadequate existing regulations; or (5) other natural or manmade factors.

We have determined that both species are threatened by destruction, modification, or curtailment of habitat or range, inadequate existing regulatory mechanisms, and other manmade factors:

This rule designates critical habitat for each species.

• We are proposing to designate critical habitat for the Neosho mucket in Arkansas, Kansas, Missouri, and Oklahoma and for the rabbitsfoot in Alabama, Arkansas, Illinois, Indiana, Kansas, Kentucky, Mississippi, Missouri, Ohio, Oklahoma, Pennsylvania, and Tennessee.

• In total, approximately 779 river kilometers (rkm) (484 river miles (rmi)) in the Cottonwood, Elk, Fall, Illinois, Neosho, Shoal, Spring, North Fork Spring, and Verdigris Rivers are being proposed for designation as critical habitat for the Neosho mucket in Arkansas, Kansas, Missouri, and Oklahoma.

• The proposed critical habitat for the Neosho mucket is located in:

○ Benton and Washington Counties, Arkansas;

○ Allen, Chase, Cherokee, Coffey, Elk, Greenwood, Labette, Montgomery, Neosho, Wilson, and Woodson Counties, Kansas;

○ Jasper, Lawrence, McDonald, and Newton Counties, Missouri; and

○ Adair, Cherokee, and Delaware Counties, Oklahoma.

• In total, approximately 2,662 rkm (1,654 rmi) in the Neosho, Spring (Arkansas River system), Verdigris, Black, Buffalo, Little, Ouachita, Saline, Middle Fork Little Red, Spring (White River system), South Fork Spring, Strawberry, White, St. Francis, Big Sunflower, Big Black, Paint Rock, Duck, Tennessee, Red, Ohio, Allegheny, Green, Tippecanoe, Walhonding, Middle Branch North Fork Vermilion, and North Fork Vermilion Rivers and Bear, French, Muddy, Little Darby and Fish Creeks in Alabama, Arkansas, Kansas, Kentucky, Illinois, Indiana, Mississippi, Missouri, Ohio, Oklahoma, Pennsylvania, and Tennessee are being proposed for designation as critical habitat for the rabbitsfoot.

• The proposed critical habitat for the rabbitsfoot is located in:

○ Colbert, Jackson, Madison, and Marshall Counties, Alabama;

○ Arkansas, Ashley, Bradley, Clark, Cleveland, Dallas, Drew, Fulton, Grant, Hot Spring, Independence, Izard, Jackson, Lawrence, Little River, Marion, Monroe, Montgomery, Newton, Ouachita, Randolph, Saline, Searcy, Sevier, Sharp, Van Buren, White, and Woodruff Counties, Arkansas;

○ Allen and Cherokee Counties, Kansas;

○ Ballard, Green, Hart, Livingston, Logan, Marshall, and McCracken Counties, Kentucky;

○ Massac, Pulaski, and Vermilion Counties, Illinois; Carroll, Pulaski, Tippecanoe, and White Counties, Indiana; Hinds, Sunflower, Tishomingo, and Warren Counties, Mississippi;

○ Jasper, Madison, and Wayne Counties, Missouri;

○ Coshocton, Madison, Union, and Williams Counties, Ohio;

○ McCurtain and Rogers Counties, Oklahoma; Crawford, Erie, Mercer, and Venango Counties, Pennsylvania; and

○ Hardin, Hickman, Marshall, Maury, and Robertson Counties, Tennessee.

Peer review of our methods.During the public comment period, we will obtain review and opinions from knowledgeable individuals with scientific expertise on our technical assumptions, analysis, adherence to regulations, and whether or not we used the best available information in developing the proposed rule.

Information Requested

We intend that any final action resulting from this proposal will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from the public, other concerned governmental agencies, Native American tribes, the scientific community, industry, or any other interested party concerning this proposed rule. We particularly seek comments concerning:

(1) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to these species and regulations that may be addressing those threats.

(2) Additional information concerning the historical and current status, range, distribution, and population size of these species, including the locations of any additional populations of these species.

(3) Any information on the biological or ecological requirements of the species and ongoing conservation measures for the species and their habitat.

(4) Any information regarding water quality data that may be helpful in determining the water quality parameters necessary for Neosho mucket and rabbitsfoot.

(5) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531et seq.), including whether there are threats to the species from human activity, the degree of which can be expected to increase due to the designation, and whether that increase in threat outweighs the benefit of designation such that the designation of critical habitat is not prudent.

(6) Specific information on:

(a) The amount and distribution of Neosho mucket and rabbitsfoot habitat;

(b) What areas, that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of the species, should be included in the designation and why;

(c) What areas not occupied at the time of listing are essential for the conservation of the species and why.

(7) Land use designations and current or planned activities in the areas occupied by the species or proposed to be designated as critical habitat, and possible impacts of these activities on these species and proposed critical habitat.

(8) Information on the projected and reasonably likely impacts of climate change on the Neosho mucket and rabbitsfoot and proposed critical habitat.

(9) Any foreseeable economic, national security, or other relevant impacts that may result from designating any area that may be included in the final designation. We are particularly interested in any impacts on small entities, and the benefits of including or excluding areas from the proposed designation that are subject to these impacts.

(10) Whether our approach to designating critical habitat could be improved or modified in any way to provide for greater public participation and understanding, or to assist us in accommodating public concerns and comments.

(11) The likelihood of adverse social reactions to the designation of critical habitat and how the consequences of such reactions, if likely to occur, would relate to the conservation and regulatory benefits of the proposed critical habitat designation.

Please note that submissions merely stating support for or opposition to the action under consideration without providing supporting information, although noted, will not be considered in making a determination, as section 4(b)(1)(A) of the Act directs that determinations as to whether any species is a threatened or endangered species must be made “solely on the basis of the best scientific and commercial data available.”

You may submit your comments and materials concerning this proposed rule by one of the methods listed in theADDRESSESsection. We request that you send comments only by the methods described in theADDRESSESsection.

If you submit information via,your entire submission—including any personal identifying information—will be posted on the Web site. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on include sufficient information with your comments to allow us to verify any scientific or commercial information you include.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on,or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Arkansas Ecological Services Office, Conway, Arkansas (seeFOR FURTHER INFORMATION CONTACT).

Previous Federal Actions Neosho Mucket

The Neosho mucket was first identified as a candidate for protection under the Act in the May 22, 1984,Federal Register(49 FR 21664) notice. As a candidate, it was assigned a status Category 2 designation, which was given to those species with some evidence of vulnerability but for which additional biological information was needed to support a proposed rule to list as endangered or threatened. In our Notices of Review dated January 6, 1989 (54 FR 554), November 21, 1991 (56 FR 58804), and November 15, 1994 (59 FR 58982), we retained a status Category 2 designation for this species. We discontinued assigning categories to candidate species in our Notice of Review dated February 28, 1996 (61 FR 7596), and only species for which the Service had sufficient information on biological vulnerability and threats to support issuance of a proposed rule were regarded as candidate species. Thus, Neosho mucket was no longer considered a candidate species.

On October 30, 2001, we identified the Neosho mucket in theFederal Register(66 FR 54808) as a candidate species based on available information to support a proposed rule. Candidate species are assigned listing priority numbers (LPNs) based on immediacy and magnitude of threats, as well as taxonomic status. The lower the LPN, the higher priority that species is for us to determine appropriate action using our available resources. We assigned an LPN of 5 to Neosho mucket. In our Notices of Review dated June 13, 2002 (67 FR 40657), and May 4, 2004 (69 FR 24876), we maintained an LPN of 5.

We published a petition finding for the Neosho mucket on May 11, 2005 (70 FR 24870), in response to a petition received on May 11, 2004, stating in the finding that the Neosho mucket would retain an LPN of 5. In our Notices of Review dated September 12, 2006 (71 FR 53756), December 6, 2007 (72 FR 69034), and December 8, 2008 (73 FR 75176), we maintained an LPN of 5, reflecting the nonimminent threats of high magnitude. The LPN was elevated to 2 in our Notice of Review dated November 10, 2010 (75 FR 69222), to reflect the change from nonimminent to imminent threats of high magnitude.


The rabbitsfoot was first identified as a candidate for protection under the Act in the November 15, 1994,Federal Register(59 FR 58982). As a candidate, it was assigned a status Category 2 designation. The category 2 list was eliminated in 1996 (61 FR 7596). On November 9, 2009, we added the rabbitsfoot to our candidate list in theFederal Register(74 FR 57804) with an LPN of 9. An LPN of 9 indicates threats of a moderate magnitude; some of the threats are nonimminent, most are ongoing, and the threats are imminent overall. In our Notice of Review dated November 10, 2010 (75 FR 69222), it was again identified as a candidate species with an LPN of 9.

Status Assessment for Neosho Mucket and Rabbitsfoot Background

It is our intent to discuss below only those topics directly relevant to the listing of the Neosho mucket as endangered and the rabbitsfoot as threatened in this section of the proposed rule.


North American freshwater mussel fauna is the richest in the world and historically numbered around 300 species (Williamset al.1993, p. 6). Freshwater mussels are in decline, however, and in the past century have become more imperiled than any other group of organisms (Williamset al.2008, p. 55). Approximately 66 percent of North America's freshwater mussel species are considered vulnerable to extinction or possibly extinct (Williamset al.1993, p. 6). Within North America, the southeastern United States is the hot spot for mussel diversity. Seventy-five percent of southeastern mussel species are in varying degrees of rarity or possibly extinct (Neveset al.1997, pp. 47-51). The central reason for the decline of freshwater mussels is the modification and destruction of their habitat, especially from sedimentation, dams, and degraded water quality (Neveset al.1997, p. 60). These two mussels, like many other southeastern mussel species, have undergone reductions in total range and population density.

General Biology

Freshwater mussels generally live embedded in the bottom of rivers, streams, and other bodies of water. They siphon water into their shells and across four gills that are specialized for respiration and food collection. Food items include algae, bacteria, detritus (disintegrated organic debris), and microscopic animals (Strayeret al.2004, pp. 430-431). It also has been surmised that dissolved organic matter may be a significant source of nutrition (Strayeret al.2004, p. 430). Adults are filter feeders and generally orient themselves on or near the substrate surface to take in food and oxygen from the water column. Juveniles typically burrow completely beneath the substrate surface and are pedal (foot) feeders (bringing food particles inside the shell for ingestion that adhere to the foot while it is extended outside the shell) until the structures for filter feeding are more fully developed (Yeageret al.1994, pp. 200-221; Gatenbyet al.1996, p. 604).

Sexes in unionid (refers to taxonomic family Unionidae) mussels, such as the Neosho mucket and rabbitsfoot, are usually separate. Males release sperm into the water column, which are drawn in by females through their siphons during feeding and respiration. Fertilization takes place inside the shell, and success is apparently influenced by mussel density and water flow conditions (Downinget al.1993, pp. 153-154). The eggs are retained in the gills of the female until they develop into mature larvae called glochidia. The glochidia of most freshwater mussel species, including the two species addressed in this rule, have a parasitic stage during which they must attach to the gills, fins, or skin of a fish to transform into a juvenile mussel. Depending on the mussel species, females release glochidia either separately, in masses known as conglutinates (gelatinous or jelly-like), or in one large mass known as a super-conglutinate. The duration of the parasitic stage varies by mussel species, water temperature, and perhaps host fish species. When the transformation is complete, the juvenile mussels drop from their fish host and sink to the stream bottom where, given suitable conditions, they grow and mature into adults. Host specificity is discussed in more detail below.

Growth rates for mussels are highly variable among individual mussel species, but overall, mussels tend to grow relatively rapidly for the first few years (Scruggs 1960, pp. 28-30; Negus 1966, pp. 517-518) then slow appreciably (Bruenderman and Neves 1993, p. 88; Hove and Neves 1994, pp. 34-36). This reduction in growth rate is correlated to sexual maturity, probably as a result of energy being diverted from growth to gamete production (Baird 2000, pp. 63-71). Heavy-shelled species, such as Neosho mucket and rabbitsfoot, grow slowly relative to thin-shelled species (Coonet al.1977, pp. 19-21; Hove and Neves 1994, p. 38).

Strayer (1999a, pp. 468 and 472) demonstrated that mussels in streams occur chiefly in “flow refuges” (relatively stable areas that displayed little movement of substrate particles during flood events). Other researchersalso concluded that mussel location and density are greatest in areas where shear stress (stream's ability to entrain and transport bed material created by the flow acting on the bed material) is low and sediments remain generally stable during flooding (Layzer and Madison 1995, p. 341; Strayer 1999a, pp. 468 and 472; Hastieet al.2001, pp. 111-114). These “flow refuges” conceivably allow relatively immobile mussels, such as the Neosho mucket and rabbitsfoot, to remain in the same general location throughout their life span. However, these areas may be more important for the rabbitsfoot since it typically does not burrow like the Neosho mucket, making it more susceptible to displacement into unsuitable habitat. However, flow refuges are not created equally and other habitat variables are important, but poorly understood (Roberts 2008, pers. comm.).

Taxonomy, Life History, and Distribution

The Neosho mucket and rabbitsfoot are freshwater mussels in the family Unionidae. Both species are currently deemed valid by the Committee on Scientific and Vernacular Names of Mollusks of the Council of Systematic Malacologists and the American Malacological Union (Turgeonet al.1998, pp. 35 and 37).

Neosho Mucket

Neosho mucket was originally described asLampsilis rafinesqueanafrom Indian Creek, McDonald County, Missouri (Frierson 1927, pp. 69-70). There is no synonomy (scientific names previously describing the same species) of the Neosho mucket. Frierson (1927, pp. 69-70) described the Neosho mucket as a dimorphic (male and female shape differs) species; the male is elliptical, rounded before biangulate behind, with dorsal and basal margin equally arched, while the female is ovate with a widely expanded fan-shaped posterior. The shell is up to 9.5 centimeters (cm) (4 inches (in)), compressed, and relatively thin (Oesch 1984, pp. 219-221). The epidermis is olive-yellow to brown, becoming darker brown with age; green rays cover the surface, but are often discontinuous. Oesch (1984, pp. 219-221) describes the left valve as having two stout, divergent, striated, triangular pseudocardinal teeth. The two lateral teeth are short, stout, and slightly curved. The right valve has a single, tall, triangular to columnar, striated pseudocardinal tooth. The nacre (crystalline carbonate shell material of freshwater mussels) is bluish white to white.

Neosho mucket glochidia are an obligate parasite on smallmouth bass (Micropterus dolomieu), largemouth bass (Micropterus salmoides), and spotted bass (Micropterus punctulatus) (Barnhart and Roberts 1997, p. 18; U.S. Fish and Wildlife Service 2005, p. 7). Neosho mucket is unusual among otherLampsilisspecies in the timing of reproduction. Neosho mucket spawns in late April and May, and female brooding occurs May through August. Most otherLampsilisspawn in the late summer or fall and brood glochidia throughout the winter months into the following spring or summer. Barnhart (2003, p. 9) reported an average fecundity to be approximately 1.3 million glochidia per female in the Spring River, Kansas. The female Neosho mucket inflates and extends a pair of mantle flaps (actually an extension of the inner lobe of the mantle edge) that, from a side angle, remarkably resembles a small fish. Each mantle flap in addition to its fish-like shape has pigmentation that resembles an eyespot as well as a fish's lateral line. Muscular contractions of the mantle flaps create an undulating or “swimming” motion that suffices to lure fish hosts (Obermeyer 2000, p. 9).

The Neosho mucket is associated with shallow riffles and runs comprising gravel substrate and moderate to swift currents. The species is most often found in areas with swift current, but in Shoal Creek and the Illinois River it prefers near-shore areas or areas out of the main current (Oesch 1984, p. 221; Obermeyer 2000, pp. 15-16). Neosho mucket historically occurred in at least 16 streams within the Illinois, Neosho, and Verdigris River basins covering four states (Arkansas, Kansas, Oklahoma, and Missouri). It is endemic to the Arkansas River system (Gordon 1980, pp. 318 and 347; Harris and Gordon 1987, pp. 53-54; Obermeyer 1996, pp. 3-4; Vaughn 1996, pp. 3-5; Mather 1990, pp. 7-13; Obermeyeret al.1997a, pp. 44-47; Harriset al.2009, p. 68). The Neosho mucket's known river and creek occurrences and current status are shown in Table 1.

For the purposes of this rule, a population is considered extant if live individuals or fresh dead specimens have been located since 1985. A population is considered viable if it is sizeable, comprised of different age classes, recruiting juveniles, and able to sustain itself over several decades without human intervention (Butler 2005, p. 23). Population trend estimates were generally made with a 20- to 30-year perspective when adequate historical information was available. Populations were deemed to have improving, stable, declining, or unknown status (Table 1).

Table 1—Neosho Mucket River and Creek Occurrences and Current Population Status River basin River/Creek State(s) Current status Date of last observation Neosho River Neosho River KS, OK Declining 2000. Cottonwood River KS Unknown 2011. South Fork Cottonwood River KS Extirpated Pre-1979. Spring River KS, MO, OK Stable 2010. North Fork Spring River MO Declining 1995. Center Creek KS, MO Extirpated 1995. Shoal Creek KS, MO Declining 2001. Elk River MO, OK Declining 1995. Indian Creek MO Extirpated Pre-1980. Little Sugar Creek MO Extirpated Pre-1980. Illinois River Illinois River AR, OK Declining 2008 Verdigris River Verdigris River KS, OK Declining 2010 Otter Creek KS Extirpated Pre-1993. Fall River KS Declining 2004. Elk River KS Extirpated Pre-1979. Caney River KS, OK Extirpated Pre-1979. Neosho River Basin

Neosho River:The Neosho River drains southeast through Kansas and Oklahoma. Historical data of Neosho mucket densities for the Neosho River are not available prior to the late 1970s (Obermeyeret al.1997b, p. 112). Mussel harvest records from the early 1900s provide useful insight on the abundance of mussels in the river. From 1911 through 1912, the Neosho River provided 17 percent or approximately 85 million mussels used in the nation's pearl button industry. Many of the 30 tons of mussel shells processed weekly in 1918 at a shell blank factory in Iola, Kansas, came from the Neosho River near LeRoy, Kansas (Obermeyeret al.1997b, p. 112).

Since the 1990s, extant populations have been found downstream of John Redmond Reservoir Dam to near Parsons, Kansas, in Allen, Coffey, Labette, and Neosho Counties, Kansas. In addition, fresh dead or relict (shell shows no sign of recent mortality, such as tissue inside shell or outer shell material (periostracum) is weathered) shells were collected at 11 sites extending to near the Kansas-Oklahoma state line in Cherokee County, Kansas (Obermeyeret al.1997a, pp. 44-46; Obermeyer 2000, pp. 8-9). In 1994, Obermeyeret al.(1995, p. 24) collected 32 live Neosho mucket specimens (relative abundance = 0.6 percent) at 7 of 19 sites in Kansas. The Neosho mucket is becoming increasingly rare in the Oklahoma segment of the river (Tabor 2011, pers. comm.) with searches yielding no live or recently dead specimens. However, relict Neosho mucket shells confirm the historical presence of the species (Mather 1990, pp. 16-17; Vaughn 1996, p. 3; 1997, pp. 7-9).

Cottonwood River:The Cottonwood River drains easterly through eastern Kansas. There are few historical records of Neosho mucket from the Cottonwood River prior to the late 1970s. Obemeyeret al.(1997a, p. 111) collected 59 live mussels from 6 sites surveyed from 1993 through 1995, but only found weathered dead shells of Neosho mucket. Neosho mucket was considered extirpated from the Cottonwood River until Kansas Department of Wildlife and Parks (KDWP) reintroduced mature male and brooding female Neosho mucket individuals at two sites east of Cottonwood Falls, Chase County, Kansas, in 2011 (Tabor and Barnhart 2012, pers. comm.).

Spring River:The Spring River drains southwesterly through southwest Missouri, southeast Kansas, and eastern Oklahoma. There are few historical records of Neosho mucket from the Spring River prior to the late 1970s. Miscellaneous records from 1979 to 2010 report 10 localities yielding 119 live Neosho mucket specimens between Missouri Highway 97 near Stott City, Lawrence County, Missouri, and the Missouri and Kansas state line (McMurray 2011, pers. comm.). Cope (1985, pp. 19-20, 26-27, 33-34) collected 424 live Neosho mucket specimens out of 993 live mussels collected in 79 total one-square-meter quadrat samples from three Kansas sites upstream of Empire Lake.

Obermeyer (1996, p. 11) provides the most comprehensive status assessment of Neosho mucket in the Spring River. He collected 1,104 live Neosho mucket specimens from 13 of 20 sites extending from Missouri Highway 97 downstream to near the Turkey Creek confluence in Kansas. The KDWP surveyed a site approximately 0.5 to 0.8 rkm (0.3 to 0.5 rmi) downstream of the Kansas and Missouri state line in 2003 and collected 201 live Neosho mucket specimens (approximately 30 percent of live mussels collected). In 2006, KDWP collected 141 live Neosho mucket specimens (approximately 30 percent of live mussels collected) at a site just upstream of the Kansas and Missouri Highway YY (Miller 2011, pers. comm.). Eight to 10 percent of live Neosho mucket specimens collected at the 2006 site were quantitatively aged at less than 5 years (Tabor 2008, pers. comm.). A 2010 survey, 6 km (4 miles) east of Crestline, Kansas, found 400 live mussel specimens, of which approximately half were Neosho mucket (Tabor 2011, pers. comm.). The Spring River Neosho mucket population represents the only viable population rangewide.

North Fork Spring River:The North Fork Spring River is a tributary of the Spring River in Missouri. There are no historical records for Neosho mucket in the North Fork Spring River prior to 1980. Neosho mucket distribution is limited to a few sites downstream of the Dry Fork confluence southwest of Jasper, Jasper County, Missouri. Three sites yielded 136 live Neosho mucket specimens in the mid 1990s (Obermeyeret al.1997a, p. 45; McMurray 2011, pers. comm.).

Shoal Creek:Shoal Creek is a southern tributary of the Spring River draining portions of southwest Missouri and southeast Kansas. There are few historical records for Neosho mucket in Shoal Creek prior to 1979. Surveys of Shoal Creek conducted from 1979 to 2001 from Missouri Highway W near Ritchey, Missouri, to Empire Lake, Cherokee County, Kansas, yielded 75 live Neosho mucket specimens from 11 sites (Obermeyeret al.1995, p. 45; McMurray 2011, pers. comm.). No specimens were found in the Kansas portion of Shoal Creek.

Elk River:The Elk River, a tributary of the Spring River, drains southwestern Missouri and northeastern Oklahoma. The Oklahoma reach downstream of Buffalo Creek just west of the Missouri and Oklahoma state line is inundated by Grand Lake O' the Cherokees, resulting in the loss of Neosho mucket habitat. Live Neosho mucket individuals have been collected from two sites in Missouri, eight individuals in 1978 and two individuals in 1995, and the species is rare from Noel, Missouri, to the Kansas and Missouri state line (McMurray 2011, pers. comm.). Brooding Neosho mucket females and juveniles were reported in this reach at two sites in 1992 and 1998 (Barnhart 2008, pers. comm.).

Illinois River Basin

Illinois River:The Illinois River drains portions of northwest Arkansas and northeast Oklahoma. There are few historical records of Neosho mucket from the Illinois River prior to the late 1970s. In 1978, Gordonet al.(1979, pp. 35-36) surveyed 16 sites between Hogeye and Siloam Springs, Arkansas, but only report Neosho mucket as part of the mussel fauna. Eighteen live Neosho mucket specimens were reported from four Arkansas locations in the early 1990s, including the only specimen ever collected from the Muddy Fork Illinois River (Harris 1991, p. 7; Environmental and Gas Consulting, Inc. 1994, pp. field data sheets). Harris (1998) conducted a status survey of the Neosho mucket and found live specimens at 19 of 22 sites in the 48 rkm (30 rmi) reach, Washington and Benton Counties, Arkansas. Neosho mucket was the third most abundant species collected, but there was little evidence of recent recruitment (Harris 1998, p. 5).

In 2005, 92 live Neosho mucket specimens were collected from two Benton County, Arkansas, sites (Robinson Road Bridge and 800 m (2,624 feet) downstream of Chambers Spring Road, Benton County, Arkansas; Posey 2005, pers. comm.). The Arkansas Game and Fish Commission (AGFC) and the Service conducted a comprehensive status survey for Neosho mucket in the Arkansas portion of the Illinois River in 2008. Live specimens of Neosho mucket were collected at 9 of 15 survey sites. There was a 32 and 53 percent decline in number of extant (still in existence) mussel sites and sites inhabited by live Neosho mucket specimens, respectively, versus the Harris (1998) status survey. Sixty-seven percent of the sites withNeosho mucket present were represented by three or fewer live specimens. Neosho mucket was the fourth most abundant species in this portion of the river, but 3 sites accounted for 85 percent of live Neosho mucket specimens (52 individuals) collected during this survey. Of the 15 survey sites, only 2 appear stable with the rest in decline, indicating imminent extirpation. No mussels were collected at the sites AGFC sampled in 2005 in 2008 further documenting the precipitous decline of mussels in the Arkansas portion of the Illinois River (Davidson 2011, pers. comm.).

Neosho mucket was locally common prior to the late 1990s in approximately 89 rkm (55 rmi) of the Illinois River from the Oklahoma and Arkansas state line downstream to Lake Tenkiller, Cherokee County, Oklahoma (Mather 1990, pp. 7-11). The population within the survey reach was estimated at more than 1,200 individuals in 1990. In 1995, Vaughn (1995, p. 3; 1997, p. 14) estimated the Neosho mucket population in the same reach surveyed by Mather in 1990 at between 500 and 1,000 individuals and locally common at 9 of 52 sites. Although some evidence of reproductive potential was observed during 1990 and 1995 (for example, gravid females displaying mantle lures), there was little evidence of recruitment into the population. Neosho mucket specimens were not found in or downstream of Lake Tenkiller.

Verdigris River Basin

Fall River:The Fall River is a southern tributary of the Verdigris River in southeast Kansas. There are few historical records from the Fall River prior to the mid 1990s (Obermeyeret al.1995, p. 24). In 1994, Obermeyeret al.(1995 p. 24) found 34 live specimens (relative abundance = 1.7 percent) from 5 sites in the Fall River, with little evidence of recruitment into the population. In 2004, two sites were resurveyed and Neosho mucket composed 1.0 and 0.5 percent of qualitative and quantitative surveys, respectively (Tabor 2008, pers. comm.). All specimens were found downstream of Fall River Lake in Greenwood, Elk, and Wilson Counties (Obermeyeret al.1995, p. 24).

Verdigris River:The Verdigris River flows through southeast Kansas and northeast Oklahoma until it reaches the Arkansas River in Oklahoma. There are few historical records from the Verdigris River in either State prior to the 1990s. Obermeyeret al.(1997a, p. 44; 1997b, p. 111) collected five Neosho mucket specimens from 4 of 14 sites from 1993 to 1995, representing 0.2 percent of the total sample from the Verdigris River between Altoona, Wilson County, Kansas, and Sycamore, Montgomery County, Kansas. The KDWP surveyed eight sites between the Fall and Verdigris River and Elk and Verdigris River confluences in 2003 and 2010. Six live Neosho mucket specimens were collected from two of these sites in 2003 (0.1 percent of the total mussel community) and seven live specimens from four sites in 2010 (0.2 percent of the total mussel community). Overall relative abundance of Neosho mucket in the Verdigris River in Kansas has ranged between 0.1 to 0.3 percent in the years from 1993 to 2010 (Miller 2011, pp. 1-2).

The majority of the Oklahoma reach has been inundated (Oologah Lake) and channelized as part of the McClellan-Kerr Arkansas River Navigation System. In 1996 and 1997, searches in the Verdigris in Oklahoma found no live Neosho mucket specimens at 32 sites. However, relict Neosho mucket shells confirmed the historical presence of the species (Vaughn 1996, p. 3; 1997, pp. 7-9). In 2008, researchers confirmed that the species is still extirpated from the Oklahoma reach (Boeckman 2008, pers. comm.).

Summary of Neosho Mucket Rangewide Population Status

The Neosho mucket is declining rangewide, with the exception of one population. Based on historical and current data, Neosho mucket has been extirpated from approximately 1,342 rkm (834 rmi) of its historical range (62 percent). Most of this extirpation has occurred within the Oklahoma and Kansas portions of its range. The extirpation of this species from numerous streams and stream reaches within its historical range signifies that substantial population losses have occurred. Extant populations are disjunct (not contiguous) in approximately 819 rkm (509 rmi). The Spring River in Missouri supports the only viable population based on the presence of a large number of individuals and evidence of recent recruitment. Given this compilation of current distribution, abundance, and status trend information, the Neosho mucket exhibits range reductions and population declines throughout its range.


The rabbitsfoot was originally described asUnio cylindricus(Say, 1817, no pagination but p. 13 of publication). The type locality is the Wabash River (Parmalee and Bogan 1998, p. 210), probably in the vicinity of New Harmony, Posey County, Indiana, and adjacent Illinois. Parmalee and Bogan (1998, p. 210) summarize the synonomy of the rabbitsfoot. The rabbitsfoot has been considered a member of the generaUnio, Mya, Margarita, Margaron,andOrthonymusat various times in history. It was first considered a member of the genusQuadrulaby Lewis (1870, p. 218). The description ofU. cylindricus strigillatusB.H. Wright, 1898 (=Q. cylindrica strigillata,the federally endangered rough rabbitsfoot; Turgeonet al.1998, p. 37), rendered the rabbitsfoot,Q. c. cylindrica,a subspecies forQ. cylindrica.Davis and Fuller (1981, p. 241) and Sprouleset al.(2006, p. 3) conducted taxonomic and genetic studies on the rough rabbitsfoot (Q. c. strigillata) and rabbitsfoot (Q. c. cylindrica). Although discussion continues over the correct taxonomic placement of the rabbitsfoot, the designation of the rabbitsfoot as a species would not affect its qualification for listing under the Act as it would qualify as a listable entity whether it was a subspecies or a species.

The rabbitsfoot is a medium to large mussel, elongate and rectangular, reaching 12 cm (6 inches) in length (Oesch 1984, pp. 91-93). Parmalee and Bogan (1998, pp. 210-212) describe the beaks as moderately elevated and raised only slightly above the hinge line. Beak sculpture consists of a few strong ridges or folds continuing onto the newer growth of the umbo (raised or domed part of the dorsal margin of the shell) as small tubercles (small, rounded projection on surface of the shell). Shell sculpture consists of a few large, rounded, low tubercles on the posterior slope, although some individuals will have numerous small, elongated pustules (small raised spots) particularly on the anterior. The periostracum (external shell surface) is generally smooth and yellowish, greenish, or olive in color becoming darker and yellowish-brown with age and usually covered with dark green or nearly black chevrons and triangles pointed ventrally (Say 1817, p. 13). These patterns are absent in some individuals.

Internally, the color of the nacre is white and iridescent, often with a grayish-green tinge in the umbo cavity. Specimens from the southern periphery of its range are occasionally purplish. Soft parts generally have an orange coloration (Oesch 1984, p. 91; Parmalee and Bogan 1998, pp. 211-212). However, Vidrine (1993, p. 55) noted that the rabbitsfoot in the Ouachita River system in Louisiana had black soft parts. Aspects of the soft anatomy aredescribed by Ortmann (1912, pp. 256-257), Utterback (1915, pp. 148-149), Davis and Fuller (1981, pp. 228-233 and 241), and Oesch (1984, p. 91).

Suitable fish hosts for rabbitsfoot populations west of the Mississippi River include blacktail shiner (Cyprinella venusta) from the Black and Little River and cardinal shiner (Luxilus cardinalis), red shiner (C. lutrensis), spotfin shiner (C. spiloptera), and bluntface shiner (C. camura) from the Spring River, but host suitability information is lacking for the eastern range (Fobian 2007, p. ii). In addition, rosyface shiner (Notropis rubellus), striped shiner (L. chrysocephalus), and emerald shiner (N. atherinoides) served as hosts for rabbitsfoot, but not in all stream populations tested (Fobian 2007, p. 69).

Rabbitsfoot populations west of the Mississippi River reach sexual maturity between the ages of 4 to 6 years (Fobian 2007, p. 50). Rabbitsfoot exhibit seasonal movement towards shallower water during brooding periods, a strategy to increase host fish exposure but one that also leaves them more vulnerable to predation and fluctuating water levels, especially downstream of dams (Fobian 2007, pp. 48-49; Barnhart 2008, pers. comm.). It is a short-term brooder, with females brooding between May and late August (Fobian 2007, pp. 15-16). Similar to other species ofQuadrula,the rabbitsfoot uses all four gills as a marsupium (pouch) for its glochidia (Fobian 2007, p. 26). Female rabbitsfoot release glochidia as conglutinates (matrices holding numerous glochidia together and embryos and undeveloped ova), which mimic flatworms or similar fish prey. Fecundity (capacity of abundant production) in river basins west of the Mississippi River ranged from 46,000 to 169,000 larvae per female (Fobian 2007, p. 19).

Rabbitsfoot is primarily an inhabitant of small to medium sized streams and some larger rivers. It usually occurs in shallow water areas along the bank and adjacent runs and shoals with reduced water velocity. Specimens also may occupy deep water runs, having been reported in 2.7 to 3.7 m (9 to 12 feet) of water. Bottom substrates generally include gravel and sand (Parmalee and Bogan 1998, pp. 211-212). This species seldom burrows but lies on its side (Watters 1988, p. 13; Fobian 2007, p. 24).

Rabbitsfoot historically occurred in 140 streams within the lower Great Lakes Subbasin and Mississippi River Basin (Table 2). The historical range included Alabama, Arkansas, Georgia, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, Ohio, Oklahoma, Pennsylvania, Tennessee, and West Virginia. Rabbitsfoot populations are considered to be extant in 51 streams in 13 states (Butler 2005, pp. 18-20; Boeckman 2008, pers. comm.), representing a 64 percent decline (51 extant streams of 140 historical populations). In streams where it remains extant, populations are highly fragmented and restricted to short reaches. Based upon existing habitat use (need for flowing vs. impounded habitats) and fish host (small minnow species with limited individual ranges) data, it is unlikely that recruitment between populations or establishment of new populations could occur naturally.

Although quantitative historical abundance data are rare for rabbitsfoot, relative abundance information can be gathered from museum lots. Historical museum data indicated stable rabbitsfoot populations occurred in the Ohio, Walhonding, Big Sandy, Scioto, Olentangy, Nolin, Wabash, North Fork Vermilion, Obey, Tennessee, White, Black, Spring (White River system), Strawberry, Illinois, Glover and Cossatot Rivers (Butler 2005, p. 20). Call (1895, p. 15) considered the rabbitsfoot “abundant in the St. Francis, Saline, and Ouachita Rivers in Arkansas.”

Table 2—Rabbitsfoot River and Creek Occurrences and Current Population Status River basin River/Creek States Current status Date of last observation Lower Great Lakes Maumee River
  • St. Joseph River
  • IN, OH
  • IN, OH
  • Extirpated
  • Extirpated
  • 1927.
  • 1967.
  • Fish Creek IN, OH Declining 2009. Feeder Canal IN Extirpated 1908. St. Mary's River IN Extirpated Circa 1920. Auglaize River OH Extirpated Mid 1900s. Ohio River Ohio River IL, IN, KY, OH, PA, WV Stable 2005. Allegheny River PA Declining 2007. French Creek PA Stable 2008. Le Boeuf Creek PA Unknown 2006. Muddy Creek PA Declining 2003. Conneautee Creek PA Unknown 2006. Monongahela River PA Extirpated Circa 1890. West Fork River WV Extirpated Pre-1913. Beaver River PA Extirpated 1898. Shenango River PA Unknown 2009. Pymatuning Creek PA Extirpated 1909. Mahoning River OH, PA Extirpated Unknown. Muskingum River OH Declining 2007. Tuscarawas River OH Extirpated Circa 1990. Walhonding River OH Declining 2009. Killbuck Creek OH Extirpated Pre-1990. Mohican River OH Extirpated 1977. Black Fork Mohican River OH Extirpated Pre-1990. Little Kanawha River WV Extirpated Circa 1900. Elk River WV Extirpated Unknown. Big Sandy River KY Extirpated Circa 1800. Levisa Fork KY Extirpated 1909. Scioto River OH Extirpated 1962. Olentangy River OH Extirpated 1962. Whetstone Creek OH Extirpated Pre-1930. Big Walnut Creek OH Extirpated 1961. Alum Creek OH Extirpated 1961. Walnut Creek OH Extirpated Pre-1990. Big Darby Creek OH Declining 2002. Little Darby Creek OH Declining 2000. Deer Creek OH Extirpated Pre-1980. Ohio Brush Creek OH Extirpated 1970. Little Miami River OH Extirpated Circa 1900. Licking River KY Extirpated Circa 1990. South Fork Licking River KY Extirpated Pre-1980. Kentucky River KY Extirpated Circa 1920. South Fork Kentucky River KY Declining 1998. Salt River KY Extirpated Pre-1980. Green River KY Improving 2009. Russell Creek KY Extirpated 1908. Nolin River KY Extirpated 1983. Barren River KY Declining 1993. Drakes Creek KY Extirpated 1926. West Fork Drakes Creek KY Extirpated 1927. Rough River KY Declining 1993. Wabash River IL, IN Declining 1988. Mississinewa River IN Extirpated Pre-1990. Eel River IN Declining 2007. Tippecanoe River IN Stable 2005. Vermilion River IL Extirpated Pre-1990. North Fork Vermilion River IL Declining 2006. Middle Branch North Fork Vermilion River IL Declining 2002. Middle Fork Vermilion River IL Extirpated 1918. Salt Fork Vermilion River IL Extirpated Circa 1920. Sugar Creek IN Extirpated 1932. Embarras River IL Extirpated Circa 1980. White River IN Extirpated Circa 1960. East Fork White River IN Extirpated 1964. Driftwood River IN Extirpated Circa 1940s. Big Blue River IN Extirpated Early 1900s. Brandywine Creek IN Extirpated Pre-1990. Sugar Creek IN Extirpated Mid 1990s. Flatrock River IN Extirpated Mid 1900s. West Fork White River IN Extirpated Pre-1990. Black Creek IN Extirpated Unknown. Cumberland River Cumberland River KY, TN Extirpated 1979. Rockcastle River KY Extirpated 1911. Big South Fork KY Extirpated 1911. Beaver Creek KY Extirpated 1949. Obey River TN Extirpated 1939. East Fork Obey River TN Extirpated Unknown. Caney Fork TN Extirpated 1961. Stones River TN Extirpated 1964.