# 76 FR 61482: Endangered and Threatened Wildlife and Plants; Endangered Status for the Alabama Pearlshell, Round Ebonyshell, Southern Sandshell, Southern Kidneyshell, and Choctaw Bean, and Threatened Status for the Tapered Pigtoe, Narrow Pigtoe, and Fuzzy Pigtoe; With Critical Habitat

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-24519

## Section

- **Citation:** 76 FR 61482
- **Heading:** Endangered and Threatened Wildlife and Plants; Endangered Status for the Alabama Pearlshell, Round Ebonyshell, Southern Sandshell, Southern Kidneyshell, and Choctaw Bean, and Threatened Status for the Tapered Pigtoe, Narrow Pigtoe, and Fuzzy Pigtoe; With Critical Habitat
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Federal Register / Vol. 76 / 76 FR 61482

## Text

DEPARTMENT OF THE INTERIOR Fish and Wildlife Service 50 CFR Part 17 [FWS-R4-ES-2011-0050; MO 92210-0-0008-B2] RIN 1018-AW92 Endangered and Threatened Wildlife and Plants; Endangered Status for the Alabama Pearlshell, Round Ebonyshell, Southern Sandshell, Southern Kidneyshell, and Choctaw Bean, and Threatened Status for the Tapered Pigtoe, Narrow Pigtoe, and Fuzzy Pigtoe; With Critical Habitat AGENCY:
Fish and Wildlife Service, Interior.

ACTION:
Proposed rule.

SUMMARY:
We, the U.S. Fish and Wildlife Service, propose to list the Alabama pearlshell ( Margaritifera marrianae ), round ebonyshell ( Fusconaia rotulata ), southern sandshell ( Hamiota australis ), southern kidneyshell ( Ptychobranchus jonesi ), and Choctaw bean ( Villosa choctawensis ) as endangered, and the tapered pigtoe ( Fusconaia burkei ), narrow pigtoe ( Fusconaia escambia ), and fuzzy pigtoe ( Pleurobema strodeanum ) as threatened, under the Endangered Species Act of 1973, as amended (Act).
These eight species are endemic to portions of the Escambia River, Yellow River, and Choctawhatchee River basins of Alabama and Florida; and to localized portions of the Mobile River Basin in Alabama. These mussel species have disappeared from other portions of their natural ranges primarily due to habitat deterioration and poor water quality as a result of excessive sedimentation and environmental contaminants.
We are also proposing to designate critical habitat under the Act for these eight species. In total, approximately 2,406 (kilometers (km) (1,495) miles (mi)) of stream and river channels fall within the boundaries of the proposed critical habitat designation. The proposed critical habitat is located in Bay, Escambia, Holmes, Jackson, Okaloosa, Santa Rosa, Walton, and Washington Counties, FL; and Barbour, Bullock, Butler, Coffee, Conecuh, Covington, Crenshaw, Dale, Escambia, Geneva, Henry, Houston, Monroe, and Pike Counties, Alabama.
These proposals, if made final, would implement Federal protection provided by the Act
ed critical habitat designation. The proposed critical habitat is located in Bay, Escambia, Holmes, Jackson, Okaloosa, Santa Rosa, Walton, and Washington Counties, FL; and Barbour, Bullock, Butler, Coffee, Conecuh, Covington, Crenshaw, Dale, Escambia, Geneva, Henry, Houston, Monroe, and Pike Counties, Alabama.
These proposals, if made final, would implement Federal protection provided by the Act.

DATES:
We will accept comments received or postmarked on or before December 5, 2011. We must receive requests for public hearings, in writing, at the address shown in the ADDRESSES section by November 18, 2011.

ADDRESSES:
You may submit comments by one of the following methods:
(1) Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the Keyword box, enter Docket No. FWS-R4-ES-2011-0050, 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-2011-0050; Division of Policy and Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax Drive, MS 2042-PDM; Arlington, VA 22203.
We will not accept e-mail or faxes. We will post all comments on http://www.regulations.gov. This 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:
Don Imm, Field Supervisor, U.S. Fish and Wildlife Service, Panama City, FL, Fish and Wildlife Office, 1601 Balboa Avenue, Panama City, FL 32405; telephone 850-769-0552; facsimile 850-763-2177. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339
Comments section below for more information).
FOR FURTHER INFORMATION CONTACT:
Don Imm, Field Supervisor, U.S. Fish and Wildlife Service, Panama City, FL, Fish and Wildlife Office, 1601 Balboa Avenue, Panama City, FL 32405; telephone 850-769-0552; facsimile 850-763-2177. If you use a telecommunications device for the deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:
This document consists of: (1) A proposed rule to list the Alabama pearlshell ( Margaritifera marrianae ), round ebonyshell ( Fusconaia rotulata ), southern sandshell ( Hamiota australis ), southern kidneyshell ( Ptychobranchus jonesi ), and Choctaw bean ( Villosa choctawensis ) as endangered, and the tapered pigtoe ( Fusconaia burkei ), narrow pigtoe ( Fusconaia escambia ), and fuzzy pigtoe ( Pleurobema strodeanum ) as threatened; and (2) proposed critical habitat designations for the Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, Choctaw bean, tapered pigtoe, narrow pigtoe, and fuzzy pigtoe.
Information Requested
We intend that any final action resulting from this proposed rule 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, the scientific community, industry, or any other interested parties 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 any of these species, including the locations of any additional populations.
(3) Any information on the biological or ecological requirements of these species, and ongoing conservation measures for the species and their habitat.
regulations that may be addressing those threats.
(2) Additional information concerning the historical and current status, range, distribution, and population size of any of these species, including the locations of any additional populations.
(3) Any information on the biological or ecological requirements of these species, and ongoing conservation measures for the species and their habitat.
(4) Current or planned activities in the areas occupied by these species and possible impacts of these activities on these species.
(5) The reasons why we should or should not designate habitat as “critical habitat” under section 4 of the Act (16 U.S.C. 1531 et seq. ) including whether there are threats to these 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 may not be prudent.
(6) Specific information on:
(a) The amount and distribution of habitat for these eight mussels;
(b) What areas, that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of these species, should be included in the designation and why;
(c) Special management considerations or protection that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change; and
sels;
(b) What areas, that were occupied at the time of listing (or are currently occupied) and that contain features essential to the conservation of these species, should be included in the designation and why;
(c) Special management considerations or protection that may be needed in critical habitat areas we are proposing, including managing for the potential effects of climate change; and
(d) What areas not occupied at the time of listing are essential for the conservation of these species and why.
(7) Land use designations and current or planned activities in the subject areas and their possible impacts on proposed critical habitat.
(8) Information on the projected and reasonably likely impacts of climate change on these species and proposed critical habitat.
(9) Any probable economic, national security, or other relevant impacts of designating any area that may be included in the final designation; in particular, any impacts on small entities or families, and the benefits of including
(10) Whether any specific areas we are proposing for critical habitat designation should be considered for exclusion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area under section 4(b)(2) of the Act.
(11) Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments
sion under section 4(b)(2) of the Act, and whether the benefits of potentially excluding any specific area outweigh the benefits of including that area under section 4(b)(2) of the Act.
(11) Whether we could improve or modify our approach to designating critical habitat in any way to provide for greater public participation and understanding, or to better accommodate public concerns and comments.
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 ADDRESSES .
If you submit information via http://www.regulations.gov, 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 http://www.regulations.gov. Please 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 http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Panama City, FL, Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT )
entific 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 http://www.regulations.gov, or by appointment, during normal business hours, at the U.S. Fish and Wildlife Service, Panama City, FL, Fish and Wildlife Office (see FOR FURTHER INFORMATION CONTACT ).
Previous Federal Actions
The Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, Choctaw bean, tapered pigtoe, narrow pigtoe, and fuzzy pigtoe were first identified as candidates for protection under the Act in the May 4, 2004, Federal Register (69 FR 24876). Candidate species are assigned Listing Priority Numbers (LPNs) based on immediacy and the magnitude of threat, as well as their taxonomic status. The lower the LPN, the higher priority that species is for us to determine appropriate action using our available resources. In the 2004, 2005 (70 FR 24870), 2006 (71 FR 53756), 2007 (72 FR 69034), 2008 (73 FR 75176), 2009 (74 FR 57869), and 2010 (75 FR 69221) Federal Register Candidate Notices of Review, the Alabama pearlshell, round ebonyshell, and southern kidneyshell were identified as LPN 2 candidate species; the narrow pigtoe, southern sandshell, fuzzy pigtoe, and Choctaw bean were identified as LPN 5 candidate species; and the tapered pigtoe was identified as an LPN 11 candidate species. In our Notices of Review, we determined that publication of a proposed rule to list these species was precluded by our work on higher priority listing actions. These eight species were included in a listing petition filed by the Center for Biological Diversity on April 20, 2010. In a separate action, we found the petition presented substantial information that the species may be warranted for listing
our Notices of Review, we determined that publication of a proposed rule to list these species was precluded by our work on higher priority listing actions. These eight species were included in a listing petition filed by the Center for Biological Diversity on April 20, 2010. In a separate action, we found the petition presented substantial information that the species may be warranted for listing. Because we have already made the equivalent 12-month finding on these species through our annual candidate assessment and notice process, we have also made a determination that the species warrant listing. Therefore, we have made the requisite findings with regards to the April 20, 2010, petition.
Background
It is our intent to discuss only those topics directly relevant to the listing of the Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, and Choctaw bean as endangered; and the tapered pigtoe, narrow pigtoe and fuzzy pigtoe as threatened in this section of the proposed rule. For information relevant to the designation of critical habitat, see “Critical Habitat” section below.
Introduction
North American freshwater mussel fauna is the richest in the world and historically numbered around 300 species (Williams et 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 (Williams et al. 2008, p. 55; Natureserve 2011). Approximately 66 percent of North America's freshwater mussel species are considered vulnerable to extinction or possibly extinct (Williams et 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 (Neves et 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 (Neves et al. 1997, p
e 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 (Neves et 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 (Neves et al. 1997, p. 60; Bogan 1998, p. 376). These eight mussels, like many other southeastern mussel species, have undergone reductions in total range and population density.
These eight species are all freshwater bivalve mussels of the families Margaritiferidae and Unionidae. The Alabama pearlshell is a member of the family Margaritiferidae, while the round ebonyshell, southern sandshell, southern kidneyshell, Choctaw bean, tapered pigtoe, narrow pigtoe, and fuzzy pigtoe belong to the family Unionidae. These mussels are endemic to portions of three Coastal Plain rivers that drain south-central and southeastern Alabama and northwestern Florida: the Escambia (known as the Escambia River in Florida and the Conecuh River in Alabama), the Yellow, and the Choctawhatchee. All three rivers originate in Alabama and flow across the Florida panhandle before emptying into the Gulf of Mexico, and are entirely contained within the East Gulf Coastal Plain Physiographic Region. The Alabama pearlshell is also known from three locations in the Mobile River Basin; however, only one of those is considered to be currently occupied.
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 detritus (disintegrated organic debris), algae, diatoms, and bacteria (Strayer et al. 2004, pp. 430-431). Adults are filter feeders and generally orient themselves on or near the substrate surface to take in food and oxygen from the water column
er bodies of water. They siphon water into their shells and across four gills that are specialized for respiration and food collection. Food items include detritus (disintegrated organic debris), algae, diatoms, and bacteria (Strayer et al. 2004, pp. 430-431). 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 (Yeager et al. 1994, pp. 200-221; Gatenby et al. 1996, p. 604).
Sexes in margaritiferid and unionid mussels are usually separate. Males release sperm into the water column, which females take in through their
Survey Data
Recent distributions are based on surveys conducted from 1995 to 2011, and historical distributions are based on collections made prior to 1995. Historical distribution data from museum records and surveys dated between the late 1800s and 1994 are sparse, and most of these species were more than likely present throughout their respective river basins. Knowledge of historical and current distribution and abundance data were summarized from Butler 1989; Williams et al. 2000 (unpublished), Blalock-Herod et al. 2002, Blalock-Herod et al. 2005, Pilarczyk et al. 2006, and Gangloff and Hartfield 2009). These studies represent a compilation of museum records and recent status surveys conducted between 1990 and 2007. We also used various other sources to identify the historical and current locations occupied by these species. These include surveys, reports, and field notes prepared by biologists from the Alabama Department of Conservation and Natural Resources, Marion, AL; Geological Survey of Alabama, Tuscaloosa, AL; Florida Fish and Wildlife Conservation Commission, Gainesville, FL; U.S
etween 1990 and 2007. We also used various other sources to identify the historical and current locations occupied by these species. These include surveys, reports, and field notes prepared by biologists from the Alabama Department of Conservation and Natural Resources, Marion, AL; Geological Survey of Alabama, Tuscaloosa, AL; Florida Fish and Wildlife Conservation Commission, Gainesville, FL; U.S. Geological Survey, Gainesville, FL; Alabama Malacological Research Center, Mobile, AL; Troy University, Troy, AL; Appalachian State University, Boone, NC; various private consulting groups; and the U.S. Fish and Wildlife Service, Daphne, AL, and Panama City, FL. In addition, we obtained occurrence data from the collection databases of the Museum of Fluviatile Mollusks (MFM), Athearn collection; Auburn University Natural History Museum (AUNHM), Auburn, Alabama; and Florida Museum of Natural History (FLMNH), Gainesville, FL.
Assessing Status
Assessing the state of a freshwater mussel population is challenging. We looked at trends in distribution (range) and abundance (numbers), by comparing recent occurrence data to historical data. One difficulty of investigating temporal trends in these eight species is the lack of historical collection data within the drainages, particularly in the lower portion of the main channels. Athearn (1964, p. 134) noted the streams of western Florida were inadequately sampled, particularly the lower Choctawhatchee, Yellow, and the lower Escambia Rivers. Blalock-Herod et al. (2005, p. 2) stated that little collecting effort had been expended in the Choctawhatchee River drainage as compared to other nearby river systems like the Apalachicola and Mobile River drainages. This paucity of historical occurrence data may create the appearance of an increase in the number of localities or a larger range than historically; however, this is most likely due to increased sampling efforts
. 2) stated that little collecting effort had been expended in the Choctawhatchee River drainage as compared to other nearby river systems like the Apalachicola and Mobile River drainages. This paucity of historical occurrence data may create the appearance of an increase in the number of localities or a larger range than historically; however, this is most likely due to increased sampling efforts. We also considered each species' relative abundance in comparison to other mussel species with which they co-occur. In addition, we relied on various published documents whose authors are considered experts on these species. These publications either described the status of these species or assigned a conservation ranking, and include Williams et al. 1993, Garner et al. 2004, Blalock-Herod et al. 2005, and Williams et al. 2008.
Most of the eight species have experienced a decline in populations and numbers of individuals within populations, but not all have experienced a decline in range. Recent, targeted surveys for the Alabama pearlshell and southern kidneyshell show a dramatic decline in historical range. The southern sandshell, Choctaw bean, narrow pigtoe, fuzzy pigtoe and tapered pigtoe still occur in much of their historical range; however, their current range is fragmented and their numbers appear to be declining.
Taxonomy, Life History, and Distribution
Alabama Pearlshell
The Alabama pearlshell ( Margaritifera marrianae, Johnson 1983) is a medium-sized freshwater mussel known from a few tributaries of the Alabama and Escambia River drainages in south-central Alabama (Johnson 1983, pp. 299-304; Mirarchi et al. 2004, p. 40; Williams et al. 2008, pp. 98-99). The pearlshell is oblong and grows up to 95 millimeters (mm) (3.8 inches (in)) in length. The outside of the shell (periostracum) is smooth and shiny and somewhat roughened along the posterior slope. The inside of the shell (nacre) is whitish or purplish and moderately iridescent (refer to Johnson 1983 for a full description)
299-304; Mirarchi et al. 2004, p. 40; Williams et al. 2008, pp. 98-99). The pearlshell is oblong and grows up to 95 millimeters (mm) (3.8 inches (in)) in length. The outside of the shell (periostracum) is smooth and shiny and somewhat roughened along the posterior slope. The inside of the shell (nacre) is whitish or purplish and moderately iridescent (refer to Johnson 1983 for a full description).
The Alabama pearlshell is one of five North American species in the family Margaritiferidae. The family is represented by only two genera, Margaritifera (Schumacher 1816) and Cumberlandia (Ortmann 1912). In Alabama, each genus is represented by a single species. The spectaclecase ( Cumberlandia monodonta ) occurs in the Tennessee River Basin (Williams et al. 2008, pp. 94-95) and the Alabama pearlshell occurs in the Escambia and Alabama River basins in lower Alabama. Prior to 1983, the Alabama pearlshell was thought to be the same species as the Louisiana pearlshell ( Margaritifera hembeli Conrad 1838) (Simpson 1914; Clench and Turner 1956), a species now considered endemic to central Louisiana.
The Alabama pearlshell typically inhabits small headwater streams with mixed sand and gravel substrates, occasionally in sandy mud, with slow to moderate current. Very little is known about the life-history requirements of this species. However, Shelton (1995, p. 5 unpub. data) suggests that the Alabama pearlshell, as opposed to the Louisiana pearlshell, which occurs in large colonies, typically occurs in low numbers. The Alabama pearlshell is also believed to occur in male-female pairs. Of the 68 Alabama pearlshell observed by Shelton (1995, p. 5 unpub. data), 85 percent occurred in pairs. Males were always located upstream of the females and were typically not more than 1 meter (m) apart, and juveniles were usually found just a few inches apart. The species is believed to be a long-term brooder, where gravid females have been observed in December. The host fish and other aspects of its life history are currently unknown
helton (1995, p. 5 unpub. data), 85 percent occurred in pairs. Males were always located upstream of the females and were typically not more than 1 meter (m) apart, and juveniles were usually found just a few inches apart. The species is believed to be a long-term brooder, where gravid females have been observed in December. The host fish and other aspects of its life history are currently unknown.
Historically, the Alabama pearlshell occurred in portions of the Escambia River drainage, and has also been reported from two systems in the Alabama River drainage. The Alabama pearlshell's known historical and current occurrences, by water body and county, are shown in Table 1 below.
Table 1—Known Historical and Current Occurrences of Alabama Pearlshell Water body Drainage County State Historical or current Big Flat Creek Alabama Monroe AL Historical and Current. Brushy Creek Alabama Monroe AL Historical. Limestone Creek Alabama Monroe AL Historical. Amos Mill Creek Escambia Conecuh AL Current. Autrey Creek Escambia Conecuh AL Historical. Beaver Creek Escambia Conecuh AL Historical. Bottle Creek Escambia Conecuh AL Historical and Current. Brushy Creek Escambia Conecuh AL Historical. Burnt Corn Creek Escambia Conecuh AL Historical and Current. Horse Creek Escambia Crenshaw AL Historical. Hunter Creek Escambia Conecuh AL Historical and Current. Jordan Creek Escambia Conecuh AL Historical and Current. Little Cedar Creek Escambia Conecuh AL Historical and Current. Murder Creek Escambia Conecuh AL Historical. Otter Creek Escambia Conecuh AL Historical and Current. Sandy Creek Escambia Conecuh AL Historical and Current. The Amos Mill population, discovered in 2010, represents a new record, and possibly the only known surviving population in the Sepulga River drainage. The Burnt Corn and Otter Creek populations reaffirm historical records that had not been reported in nearly 30 years. Two of the Sandy Creek locations, discovered in 2011, are new populations
. Sandy Creek Escambia Conecuh AL Historical and Current. The Amos Mill population, discovered in 2010, represents a new record, and possibly the only known surviving population in the Sepulga River drainage. The Burnt Corn and Otter Creek populations reaffirm historical records that had not been reported in nearly 30 years. Two of the Sandy Creek locations, discovered in 2011, are new populations. Since the late 1990's, more than 70 locations within the Alabama River Basin were surveyed for mollusks (McGregor et al. 1999, pp. 13-14; Powell and Ford 2010 pers. obs.; Buntin 2011 pers. comm.; Fobian 2011 pers. comm.), 35 of which were located in the Limestone and Big Flat Creek drainages, and no live Alabama pearlshell were reported. The last documented occurrence in Big Flat Creek was a fresh dead individual collected in 1995 (Shelton 1995, p. 3 unpub. data), and the last reported occurrence in the Limestone Creek drainage was 1974 where Williams (2009 pers. comm.) reported it as common. Despite numerous visits, the pearlshell has not been collected in this system since 1974. A fresh dead individual, collected by Shelton (1998), represents the most recent record from the Big Flat Creek drainage.
Recent data suggest that, of the nine remaining populations, the largest populations may occur in Little Cedar and Otter Mill Creeks. In 2011, Fobian and Pritchett reported new populations at two locations in an unnamed tributary to Sandy Creek. Although this is not the first report from the Sandy Creek basin, it is, however, the first for the two unnamed tributaries. In 2010, Buntin and Fobian (2011 pers. comm.) reported 10 live individuals from Otter Creek. This is the first time since 1981 that the pearlshell has been reported from this drainage. Also in 2010, Powell and Ford reported 3 individuals, and several relic shells, from Amos Mill Creek, in Escambia County, AL
ort from the Sandy Creek basin, it is, however, the first for the two unnamed tributaries. In 2010, Buntin and Fobian (2011 pers. comm.) reported 10 live individuals from Otter Creek. This is the first time since 1981 that the pearlshell has been reported from this drainage. Also in 2010, Powell and Ford reported 3 individuals, and several relic shells, from Amos Mill Creek, in Escambia County, AL. This is the first report of the pearlshell from this drainage, and county, and the first live individual from the Sepulga River system in nearly 50 years. Little Cedar Creek supported good numbers of Alabama pearlshell in the late 1990's (54 individuals reported in 1998). However, during a qualitative search of the same area in 2005, only two live pearlshell were found (Powell 2005 pers. obs.), and in 2006, three live pearlshells were observed (Johnson 2006 in litt.). Live Alabama pearlshell have not been observed in Hunter Creek since 1998, when eight live individuals were reported (Shelton 1998 pers. comm.). During two visits to the stream in 1999, Shelton found no evidence of the species (Shelton 1999 in litt.), and reported high levels of sedimentation. However, in 2005 the shells of three fresh dead Alabama pearlshells were reported from Hunter Creek, indicating the persistence of the species in that drainage (Powell, pers. obs. 2005).
Evidence suggests that much of the rangewide decline of this species has occurred within the past few decades. Specific causes of the decline and disappearance of the Alabama pearlshell from historical stream localities are unknown. However, they are likely related to past and present land use patterns. Many of the small streams historically inhabited by the Alabama pearlshell are impacted to various degrees by nonpoint-source pollution.
Round Ebonyshell
The round ebonyshell ( Fusconaia rotulata, Wright 1899) is a medium-sized freshwater mussel endemic to the Escambia River drainage in Alabama and Florida (Williams et al. 2008, p. 320)
are likely related to past and present land use patterns. Many of the small streams historically inhabited by the Alabama pearlshell are impacted to various degrees by nonpoint-source pollution.
Round Ebonyshell
The round ebonyshell ( Fusconaia rotulata, Wright 1899) is a medium-sized freshwater mussel endemic to the Escambia River drainage in Alabama and Florida (Williams et al. 2008, p. 320). The round ebonyshell is round to oval in shape and reaches about 70 mm (2.8 in.) in length. The shell is thick and the outside is smooth and dark brown to black in color. The shell interior is white to silvery and iridescent (Williams and Butler 1994, p. 61; Williams et al. 2008, p. 319). The round ebonyshell was originally described by B. H. Wright in 1899 and placed in the genus Unio. Simpson (1900) reexamined the type specimen and assigned it to the genus Obovaria. Based on shell characters, Williams and Butler (1994, p. 61) recognized it as clearly a species of the genus Fusconaia, and its placement in the genus is supported genetically (Lydeard et al. 2000, p. 149).
Very little is known about the habitat requirements or life history of the round ebonyshell. It occurs typically in stable substrates of sand, small gravel, or sandy mud in slow to moderate current. It is believed to be a short-term brooder, and gravid females have been observed in the spring and summer. The fish host(s) for the round ebonyshell is currently unknown (Williams et al. 2008, p. 320).
The round ebonyshell is known only from the main channel of the Escambia-Conecuh River and is the only mussel species endemic to the drainage (Williams et al. 2008, p. 320). Due to recent survey data, its known range was extended downstream the Escambia River to near Mystic Springs in Florida (Shelton et al. 2007, p. 9 unpub. data), and upstream the Conecuh River to just above the Covington County line in Alabama (Williams et al. 2008, p. 320)
n channel of the Escambia-Conecuh River and is the only mussel species endemic to the drainage (Williams et al. 2008, p. 320). Due to recent survey data, its known range was extended downstream the Escambia River to near Mystic Springs in Florida (Shelton et al. 2007, p. 9 unpub. data), and upstream the Conecuh River to just above the Covington County line in Alabama (Williams et al. 2008, p. 320). The round ebonyshell's known historical and current occurrences, by water body and county, are shown in Table 2 below.
Table 2—Known Historical and Current Occurrences of the Round Ebonyshell Water body Drainage County State Historical or current Conecuh River Escambia Escambia, Covington AL Historical and Current. Escambia River Escambia Escambia, Santa Rosa FL Historical and Current. The round ebonyshell has one of the most restricted distributions of any North American unionid (Williams and Butler 1994, p. 61). Its current range (based on live individuals and shell material) is confined to approximately 120 km (75 mi) of river channel. The round ebonyshell is also extremely rare (Williams et al. 2008, p. 320). Researchers collected a total of three live individuals during a 2006 status survey (Shelton et al. 2007, pp. 8-10 unpub. data). At stations where the species was present, roughly 950 mussels were collected for every 1 round ebonyshell. Its limited distribution and small population size makes round ebonyshell particularly vulnerable to catastrophic events such as droughts, flood scour, and contaminant spills. Due to its limited distribution and rarity, Garner et al. (2004, p. 56) considered the round ebonyshell vulnerable to extinction, and classified it as a species of highest conservation concern in Alabama. Williams et al. (1993, p. 11) considered the round ebonyshell as endangered throughout its range
ticularly vulnerable to catastrophic events such as droughts, flood scour, and contaminant spills. Due to its limited distribution and rarity, Garner et al. (2004, p. 56) considered the round ebonyshell vulnerable to extinction, and classified it as a species of highest conservation concern in Alabama. Williams et al. (1993, p. 11) considered the round ebonyshell as endangered throughout its range.
Southern Sandshell
The southern sandshell ( Hamiota australis, Simpson 1900) is a medium-sized freshwater mussel known from the Escambia River drainage in Alabama, and the Yellow and Choctawhatchee River drainages in Alabama and Florida (Williams et al. 2008, p. 338). The southern sandshell is elliptical in shape and reaches about 83 mm (2.3 in.) in length. Its shell is smooth and shiny, and greenish in color in young specimens, becoming dark greenish brown to black with age, with many variable green rays. The shell interior is bluish white and iridescent. Sexual dimorphism is present as a slight inflation of the posterioventral shell margin of females (Williams and Butler 1994, p. 97; Williams et al. 2008, p. 337). The southern sandshell ( Hamiota australis ) was originally described by C. T. Simpson (1900) as Lampsilis australis. Heard (1979), however, designated it as a species of Villosa. It was placed in the genus Hamiota by Roe and Hartfield (2005, pp. 1-3) who confirmed earlier published suggestions by Fuller and Bereza (1973, p. 53) and O'Brien and Brim Box (1999, pp. 135-136) that this species and three others of the genus Lampsilis represent a distinct genus. This separation from other Lampsilis is supported genetically (Roe et al. 2001, p. 2230). The new genus, Hamiota, is distinguished based on several characters including unique shape and placement of the marsupia (where females brood developing larvae), and production of a single large conglutinate, termed a superconglutinate
ecies and three others of the genus Lampsilis represent a distinct genus. This separation from other Lampsilis is supported genetically (Roe et al. 2001, p. 2230). The new genus, Hamiota, is distinguished based on several characters including unique shape and placement of the marsupia (where females brood developing larvae), and production of a single large conglutinate, termed a superconglutinate.
The southern sandshell is typically found in small creeks and rivers in stable substrates of sand or mixtures of sand and fine gravel, with slow to moderate current. It is a long-term brooder, and females are gravid from late summer or autumn to the following spring (Williams et al. 2008, p. 338). The southern sandshell is one of only four species that produce a superconglutinate to attract a host. A superconglutinate is a mass that mimics the shape, coloration, and movement of a fish and is produced by the female mussel to hold the glochidia (larval mussels) from one year's reproductive effort (Haag et al. 1995, p. 472). After release, the superconglutinate is tethered to the female mussel by a mucus strand, and it appears to dart and swim in the current. Although the fish host for the southern sandshell has not been identified, it likely uses predatory sunfishes such as basses, like other Hamiota species (Haag et al. 1995, p. 475; O'Brien and Brim Box 1999, p. 134; Blalock-Herod et al. 2002, p. 1885).
The southern sandshell is endemic to the Escambia River drainage in Alabama, and the Yellow and Choctawhatchee River drainages in Alabama and Florida (Blalock-Herod et al. 2002, pp. 1882, 1884). The southern sandshell's known historical and current occurrences, by water body and county, are shown in Table 3 below.
Table 3—Known Historical and Current Occurrences of the Southern Sandshell Water body Drainage County State Historical or current Alligator Creek Choctawhatchee Washington FL Historical. Bruce Creek Choctawhatchee Walton FL Current. Choctawhatchee River Choctawhatchee Geneva AL Historical
sandshell's known historical and current occurrences, by water body and county, are shown in Table 3 below.
Table 3—Known Historical and Current Occurrences of the Southern Sandshell Water body Drainage County State Historical or current Alligator Creek Choctawhatchee Washington FL Historical. Bruce Creek Choctawhatchee Walton FL Current. Choctawhatchee River Choctawhatchee Geneva AL Historical. Choctawhatchee River Choctawhatchee Holmes, Dale FL, AL Historical and Current. Corner Creek Choctawhatchee Geneva AL Current. Double Bridges Creek Choctawhatchee Coffee AL Current. East Fork Choctawhatchee R. Choctawhatchee Henry AL Historical and Current. East Fork Choctawhatchee R. Choctawhatchee Dale AL Historical. Eightmile Creek Choctawhatchee Walton, Geneva FL, AL Current. Flat Creek Choctawhatchee Geneva AL Current. Holmes Creek Choctawhatchee Holmes FL Historical. Jordan Creek Choctawhatchee Conecuh AL Current. Limestone Creek Choctawhatchee Walton FL Historical. Little Choctawhatchee River Choctawhatchee Dale, Houston AL Historical. Natural Bridge Creek Choctawhatchee Geneva AL Current. Patsaliga Creek Choctawhatchee Crenshaw AL Current. Pauls Creek Choctawhatchee Barbour AL Current. Pea Creek (Barbour Co.) Choctawhatchee Barbour AL Historical and Current. Pea Creek (Dale Co.) Choctawhatchee Dale AL Historical. Pea River Choctawhatchee Geneva, Barbour AL Historical. Pea River Choctawhatchee Coffee, Dale, Pike AL Historical and Current. Sikes Creek Choctawhatchee Barbour AL Current. Tenmile Creek Choctawhatchee Holmes FL Historical. West Fork Choctawhatchee R. Choctawhatchee Barbour, Dale AL Historical and Current. Whitewater Creek Choctawhatchee Coffee AL Historical. Wrights Creek Choctawhatchee Holmes FL Current. Burnt Corn Creek Escambia Escambia, Conecuh AL Historical. Conecuh River Escambia Pike AL Current. Conecuh River Escambia Covington, Crenshaw AL Historical. Little Patsaliga Creek Escambia Crenshaw AL Historical. Sepulga River Escambia Conecuh AL Historical
Barbour, Dale AL Historical and Current. Whitewater Creek Choctawhatchee Coffee AL Historical. Wrights Creek Choctawhatchee Holmes FL Current. Burnt Corn Creek Escambia Escambia, Conecuh AL Historical. Conecuh River Escambia Pike AL Current. Conecuh River Escambia Covington, Crenshaw AL Historical. Little Patsaliga Creek Escambia Crenshaw AL Historical. Sepulga River Escambia Conecuh AL Historical. Five Runs Creek Yellow Covington AL Historical and Current. Pond Creek Yellow Okaloosa, Walton FL Historical. Shoal River Yellow Okaloosa FL Current. Yellow River Yellow Okaloosa FL Current. Yellow River Yellow Covington AL Historical and Current. The southern sandshell persists in its historical range; however, its range is fragmented and numbers appear to be declining (Williams et al. 2008, p. 338). The number of locations in the Escambia drainage known to support the species has declined. It is known from a total of nine locations, however, only three are recent occurrences. Also, its numbers are very low; a total of four individuals (live and shell material) have been collected in the Escambia drainage since 1995. In the Yellow River drainage, the number of locations known to support southern sandshell populations has declined from a total of 15 to 10 currently. The number of locations known to support the species in the Choctawhatchee River drainage has declined from 44 to 25 currently; and it may be extirpated from central portions of the Choctawhatchee River main channel and from some of its tributaries. Sedimentation could be one factor contributing to its decline. In order to reproduce, the southern sandshell must attract a site-feeding fish to its superconglutinate lure. Waters clouded by silt and sediment would reduce the chance of this interaction occurring (Haag et al. 1995, p. 475).
The southern sandshell is classified as a species of highest conservation concern in Alabama by Garner et al. (2004, p. 60), and considered threatened throughout its range by Williams et al. (1993, p. 11)
n sandshell must attract a site-feeding fish to its superconglutinate lure. Waters clouded by silt and sediment would reduce the chance of this interaction occurring (Haag et al. 1995, p. 475).
The southern sandshell is classified as a species of highest conservation concern in Alabama by Garner et al. (2004, p. 60), and considered threatened throughout its range by Williams et al. (1993, p. 11).
Southern Kidneyshell
The southern kidneyshell ( Ptychobranchus jonesi, van der Schalie 1934) is a medium-sized freshwater mussel known from the Escambia and Choctawhatchee River drainages in Alabama and Florida, and the Yellow River drainage in Alabama (Williams et al. 2008, p. 624). The southern kidneyshell is elliptical and reaches about 72 mm (2.8 in.) in length. Its shell is smooth and shiny, and greenish yellow to dark brown or black in color, sometimes with weak rays. The shell interior is bluish white with some iridescence (Williams and Butler 1994, p. 126; Williams et al. 2008, p. 624). The southern kidneyshell was described by H. van der Schalie (1934) as Lampsilis jonesi. Following the examination of gills of gravid females, Fuller and Bereza (1973, p. 53) determined it belonged in the genus Ptychobranchus. When gravid, the marsupial gills form folds along the outer edge, a characteristic unique to the genus Ptychobranchus (Williams et al. 2008, p. 609).
Very little is known about the habitat requirements or life history of the southern kidneyshell. It is typically found in medium creeks to medium rivers in firm sand substrates with slow to moderate current (Williams et al. 2008, pp. 625). A recent status survey in the Choctawhatchee basin in Alabama found its preferred habitat to be stable substrates near bedrock outcroppings (Gangloff and Hartfield 2009, p. 25). The southern kidneyshell is believed to be a long-term brooder, with females gravid from autumn to the following spring or summer
ivers in firm sand substrates with slow to moderate current (Williams et al. 2008, pp. 625). A recent status survey in the Choctawhatchee basin in Alabama found its preferred habitat to be stable substrates near bedrock outcroppings (Gangloff and Hartfield 2009, p. 25). The southern kidneyshell is believed to be a long-term brooder, with females gravid from autumn to the following spring or summer. Preliminary reproductive studies found that females release their glochidia in small conglutinates that are bulbous at one end and tapered at the other (Alabama Aquatic Biodiversity Center 2006 unpub. data). Host fish for the southern kidneyshell are currently unknown; however, darters serve as primary glochidial hosts to other members of the genus Ptychobranchus (Luo 1993, p. 16; Haag and Warren 1997, p. 580).
The southern kidneyshell is endemic to the Escambia, Choctawhatchee, and Yellow River drainages in Alabama and Florida (Williams et al. 2008, p. 624), but is currently known only from the Choctawhatchee drainage. The southern kidneyshell's known historical and current occurrences, by water body and county, are shown in Table 4 below.
Table 4—Known Historical and Current Occurrences of the Southern Kidneyshell Water body Drainage County State Historical or current Choctawhatchee River Choctawhatchee Dale AL Historical and Current. Choctawhatchee River Choctawhatchee Walton, Geneva FL, AL Historical. East Fork Choctawhatchee R Choctawhatchee Dale, Henry AL Historical. Flat Creek Choctawhatchee Geneva AL Historical. Holmes Creek Choctawhatchee Washington AL Current. Pea River Choctawhatchee Geneva AL Current. Pea River Choctawhatchee Pike, Barbour AL Historical. Pea River Choctawhatchee Coffee, Dale AL Historical and Current. Sandy Creek Choctawhatchee Walton FL Historical. West Fork Choctawhatchee R Choctawhatchee Barbour AL Historical and Current. West Fork Choctawhatchee R Choctawhatchee Dale AL Historical. Whitewater Creek Choctawhatchee Coffee AL Historical
River Choctawhatchee Geneva AL Current. Pea River Choctawhatchee Pike, Barbour AL Historical. Pea River Choctawhatchee Coffee, Dale AL Historical and Current. Sandy Creek Choctawhatchee Walton FL Historical. West Fork Choctawhatchee R Choctawhatchee Barbour AL Historical and Current. West Fork Choctawhatchee R Choctawhatchee Dale AL Historical. Whitewater Creek Choctawhatchee Coffee AL Historical. Burnt Corn Creek Escambia Escambia AL Historical. Conecuh River Escambia Covington, Crenshaw AL Historical. Jordan Creek Escambia Conecuh AL Historical. Little Patsaliga Creek Escambia Crenshaw AL Historical. Patsaliga Creek Escambia Covington, Crenshaw AL Historical. Sepulga River Escambia Conecuh AL Historical. Hollis Creek Yellow Covington AL Historical. Since 1995, the southern kidneyshell has been detected at only 10 locations within the Choctawhatchee River drainage. The species appears to have been common historically (In 1964, H. D. Athearn collected 98 individuals at one site on the West Fork Choctawhatchee), but it is currently considered one of the most imperiled species in the United States (Blalock-Herod et al. 2005, p. 16; Williams et al. 2008, p. 625). In addition to a reduction in range, its population numbers also appear to be very low. A 2006-2007 status survey in the Alabama portions of the Choctawhatchee basin found the southern kidneyshell was extremely rare. A total of 13 were encountered alive, and the species comprised less than 0.3 percent of the total mussel assemblage (Gangloff and Hartfield 2009, p. 249). It is classified as a species of highest conservation concern in Alabama by Garner et al. (2004, p. 83), and considered threatened throughout its range by Williams et al. (1993, p. 14)
Choctaw Bean
The Choctaw bean ( Villosa choctawensis, Athearn 1964) is a small freshwater mussel known from the Escambia, Yellow, and Choctawhatchee River drainages of Alabama and Florida
artfield 2009, p. 249). It is classified as a species of highest conservation concern in Alabama by Garner et al. (2004, p. 83), and considered threatened throughout its range by Williams et al. (1993, p. 14)
Choctaw Bean
The Choctaw bean ( Villosa choctawensis, Athearn 1964) is a small freshwater mussel known from the Escambia, Yellow, and Choctawhatchee River drainages of Alabama and Florida. The oval shell of the Choctaw bean reaches about 49 mm (2.0 in.) in length, and is shiny and greenish-brown in color, typically with thin green rays, though the rays are often obscured in darker individuals. The shell interior color varies from bluish white to smoky brown with some iridescence (Williams and Butler 1994, p. 100; Williams et al. 2008, p. 758). The sexes are dimorphic, with females truncate or widely rounded posteriorly, and sometimes slightly more inflated (Athearn 1964, p. 137). The Choctaw bean was originally described by H. D. Athearn in 1964.
Very little is known about the habitat requirements or life history of the Choctaw bean. It is found in large creeks and small rivers in stable substrates of silty sand to sandy clay with moderate current. It is believed to be a long-term brooder, with females gravid from late summer or autumn to the following summer. Its fish host is currently unknown (Williams et al. 2008, p. 758).
The Choctaw bean is known from the Escambia, Yellow, and Choctawhatchee River drainages in Alabama and Florida (Williams et al. 2008, p. 758). The Choctaw bean's known historical and current occurrences, by water body and county, are shown in the table below.
Table 5—Known Historical and Current Occurrences for the Choctaw Bean Water body Drainage County State Historical or current Big Sandy Creek Choctawhatchee Bullock AL Current. Bruce Creek Choctawhatchee Walton FL Current. Choctawhatchee River Choctawhatchee Dale AL Current. Choctawhatchee River Choctawhatchee Holmes AL Historical. Choctawhatchee River Choctawhatchee Washington, Geneva FL, AL Historical and Current
torical and Current Occurrences for the Choctaw Bean Water body Drainage County State Historical or current Big Sandy Creek Choctawhatchee Bullock AL Current. Bruce Creek Choctawhatchee Walton FL Current. Choctawhatchee River Choctawhatchee Dale AL Current. Choctawhatchee River Choctawhatchee Holmes AL Historical. Choctawhatchee River Choctawhatchee Washington, Geneva FL, AL Historical and Current. Claybank Creek Choctawhatchee Dale AL Current. East Fork Choctawhatchee R. Choctawhatchee Barbour AL Current. East Fork Choctawhatchee R. Choctawhatchee Henry AL Historical and Current. Flat Creek Choctawhatchee Geneva AL Current. Holmes Creek Choctawhatchee Washington FL Current. Judy Creek Choctawhatchee Dale AL Current. Limestone Creek Choctawhatchee Walton FL Current. Paul's Creek Choctawhatchee Barbour AL Current. Pea Creek Choctawhatchee Barbour AL Current. Pea River Choctawhatchee Coffee AL Current. Pea River Choctawhatchee Geneva, Pike, Barbour AL Historical and Current. West Fork Choctawhatchee R. Choctawhatchee Dale AL Current. West Fork Choctawhatchee R. Choctawhatchee Pike, Barbour AL Historical and Current. Whitewater Creek Choctawhatchee Coffee AL Current. Wrights Creek Choctawhatchee Holmes FL Current. Conecuh River Escambia Crenshaw, Pike AL Current. Escambia River Escambia Santa Rosa FL Historical. Escambia River Escambia Escambia FL Historical and Current. Little Patsaliga Creek Escambia Crenshaw AL Historical. Murder Creek Escambia Conecuh AL Historical. Olustee Creek Escambia Pike AL Current. Patsaliga Creek Escambia Crenshaw AL Historical and Current. Pigeon Creek Escambia Butler AL Historical. Five Runs Creek Yellow Covington AL Historical and Current. Yellow River Yellow Okaloosa, Covington FL, AL Historical and Current. The Choctaw bean persists in most of its historical range. However, its populations are fragmented and its numbers are low, particularly in the Escambia and Yellow drainages
Creek Escambia Crenshaw AL Historical and Current. Pigeon Creek Escambia Butler AL Historical. Five Runs Creek Yellow Covington AL Historical and Current. Yellow River Yellow Okaloosa, Covington FL, AL Historical and Current. The Choctaw bean persists in most of its historical range. However, its populations are fragmented and its numbers are low, particularly in the Escambia and Yellow drainages. The number of locations in the Escambia River drainage known to support the species has declined from a total of 13 to 6 currently. Also, its numbers within the drainage are very low; a total of only 10 individuals have been collected since 1995. The number of locations known to support the Choctaw bean in the Yellow River drainage has declined from a total of 7 to 4 currently. Since 1995, a total of 28 individuals have been collected within the Yellow drainage. In the Choctawhatchee River drainage, the Choctaw bean continues to persist in most areas. It is known from a total of 40 locations throughout the drainage, 34 of which are recent occurrences.
Heard assessed the status of the Choctaw bean in 1975 (p. 17) and stated that it was formerly abundant in the main channel of the Choctawhatchee River in Florida, but has become quite rare. Garner et al. (2004, p. 103) considered the Choctaw bean vulnerable to extinction due to its limited distribution and habitat degradation, and classified it as a species of high conservation concern in Alabama. Williams et al. (1993, p. 14) considered the Choctaw bean as threatened throughout its range.
Tapered Pigtoe
The tapered pigtoe ( Fusconaia burkei, Walker 1922) is a small to medium-sized mussel endemic to the Choctawhatchee river drainage in Alabama and Florida (Williams et al. 2008, p. 296). The elliptical to subtriangular shell of the tapered pigtoe reaches about 75 mm (3.0 in.) in length, and is sculptured with plications (parallel ridges) that radiate from the posterior ridge
nge.
Tapered Pigtoe
The tapered pigtoe ( Fusconaia burkei, Walker 1922) is a small to medium-sized mussel endemic to the Choctawhatchee river drainage in Alabama and Florida (Williams et al. 2008, p. 296). The elliptical to subtriangular shell of the tapered pigtoe reaches about 75 mm (3.0 in.) in length, and is sculptured with plications (parallel ridges) that radiate from the posterior ridge. In younger individuals, the shell exterior is greenish brown to yellowish brown in color, occasionally with faint dark-green rays, and with pronounced sculpture often covering the entire shell; in older individuals the shell becomes dark brown to black with age and sculpture is often subtle. The shell interior is bluish white (Williams et al. 2008, p. 295). The tapered pigtoe was described by B. Walker (1922) (in Ortmann and Walker) as Quincuncina burkei, a new genus and species (the genus description was done by A. E. Ortmann and the species description by Walker). In the description, Ortmann noted the species had gill features characteristic of the genus Fusconaia; however, this was dismissed based on the presence of sculpture on the shell. Genetic analysis by Lydeard et al. (2000, p. 149) determined it to be a sister taxon to Fusconaia escambia. Based on genetic results and soft anatomy similarity, Williams et al. (2008, p. 296) recognized burkei as belonging to the genus Fusconaia.
The tapered pigtoe is found in small to medium rivers in stable substrates of sand, small gravel, or sandy mud, with slow to moderate current (Williams et al. 2008, p. 296). The reproductive biology of the tapered pigtoe was studied by White et al. (2008). It is a short-term brooder, with females gravid from mid-March to May. The blacktail shiner ( Cyprinella venusta ) was found to serve as a host for tapered pigtoe glochidia in the preliminary host trial (White et al. 2008, p. 122-123).
The tapered pigtoe is endemic to the Choctawhatchee River drainage in Alabama and Florida (Williams et al. 2008, p. 296)
igtoe was studied by White et al. (2008). It is a short-term brooder, with females gravid from mid-March to May. The blacktail shiner ( Cyprinella venusta ) was found to serve as a host for tapered pigtoe glochidia in the preliminary host trial (White et al. 2008, p. 122-123).
The tapered pigtoe is endemic to the Choctawhatchee River drainage in Alabama and Florida (Williams et al. 2008, p. 296). Its historical and current distribution includes several oxbow lakes in Florida; some with a flowing connection to main channel. The tapered pigtoe's known historical and current occurrences, by water body and county, are shown in the table below.
Table 6—Known Historical and Current Occurrences for the Tapered Pigtoe Water body Drainage County State Historical or current Bear Creek Choctawhatchee Houston AL Historical. Big Creek Choctawhatchee Barbour AL Current. Blue Creek Choctawhatchee Holmes FL Current. Bruce Creek Choctawhatchee Walton FL Current. Choctawhatchee River Choctawhatchee Dale AL Historical. Choctawhatchee River Choctawhatchee Washington, Walton, Holmes FL Historical and Current. Cowford Island channel Choctawhatchee Washington FL Historical and Current. Crawford Lake Choctawhatchee Washington FL Historical. Crews Lake Choctawhatchee Washington FL Current. East Fork Choctawhatchee R. Choctawhatchee Dale AL Historical. East Fork Choctawhatchee R. Choctawhatchee Henry AL Historical and Current. East Pittman Creek Choctawhatchee Holmes FL Historical and Current. Eightmile Creek Choctawhatchee Walton, Geneva FL, AL Current. Flat Creek Choctawhatchee Geneva AL Historical and Current. Holmes Creek Choctawhatchee Washington, Holmes, Jackson FL Historical and Current. Horseshoe Lake Choctawhatchee Washington FL Historical. Hurricane Creek Choctawhatchee Geneva AL Historical. Judy Creek Choctawhatchee Dale AL Current. Limestone Creek Choctawhatchee Walton FL Historical and Current. Little Choctawhatchee River Choctawhatchee Dale, Houston AL Historical. Panther Creek Choctawhatchee Houston AL Historical
tchee Washington, Holmes, Jackson FL Historical and Current. Horseshoe Lake Choctawhatchee Washington FL Historical. Hurricane Creek Choctawhatchee Geneva AL Historical. Judy Creek Choctawhatchee Dale AL Current. Limestone Creek Choctawhatchee Walton FL Historical and Current. Little Choctawhatchee River Choctawhatchee Dale, Houston AL Historical. Panther Creek Choctawhatchee Houston AL Historical. Parrot Creek Choctawhatchee Holmes FL Current. Paul's Creek Choctawhatchee Barbour AL Current. Pea Creek Choctawhatchee Barbour AL Current. Pea River Choctawhatchee Dale, Barbour AL Historical. Pea River Choctawhatchee Coffee, Pike AL Historical and Current. Pine Log Creek Choctawhatchee Washington, Bay FL Current. Sandy Creek Choctawhatchee Walton FL Current. Tenmile Creek Choctawhatchee Holmes FL Historical. West Fork Choctawhatchee R. Choctawhatchee Dale, Pike AL Historical. West Fork Choctawhatchee R. Choctawhatchee Barbour AL Historical and Current. West Pittman Creek Choctawhatchee Holmes FL Current. Wrights Creek Choctawhatchee Holmes FL Current. The tapered pigtoe appears to be absent from portions of its historical range and found only in isolated locations (Blalock-Herod et al. 2005, p. 17). The species is known from a total of 60 locations within the Choctawhatchee River drainage. It was not detected at 11 historical sites examined during recent status surveys (9 additional historic locations were not examined). Many of those historic occurrences are in the middle section of the drainage, and the species appears to be declining in that portion of its range. The tapered pigtoe continues to persist in isolated locations, mainly in the Choctawhatchee River main channel in Florida and in the headwaters in Alabama.
Due to its limited distribution, rarity, and habitat degradation, Garner et al. (2004, p. 105) consider the tapered pigtoe vulnerable to extinction, and classified it as a species of high conservation concern in Alabama
portion of its range. The tapered pigtoe continues to persist in isolated locations, mainly in the Choctawhatchee River main channel in Florida and in the headwaters in Alabama.
Due to its limited distribution, rarity, and habitat degradation, Garner et al. (2004, p. 105) consider the tapered pigtoe vulnerable to extinction, and classified it as a species of high conservation concern in Alabama. The tapered pigtoe is considered threatened throughout its range by Williams et al. (1993, p. 14).
Narrow Pigtoe
The narrow pigtoe ( Fusconaia escambia, Clench and Turner 1956) is a small to medium-sized mussel known from the Escambia River drainage in Alabama and Florida, and the Yellow River drainage in Florida. The subtriangular to squarish shaped shell of the narrow pigtoe reaches about 75 mm (3.0 in.) in length. The shell is moderately thick and is usually reddish brown to black in color. The shell interior is white to salmon in color with iridescence near the posterior margin (Williams and Butler 1994, p. 77; Williams et al. 2008, p. 316). The narrow pigtoe was originally described by W.J. Clench and R.D. Turner in 1956.
Little is known about the habitat requirements or life history of the narrow pigtoe. It is found in creeks and small to medium rivers in stable substrates of sand, sand and gravel, or silty sand, with slow to moderate current. It is believed to be a short-term brooder, with females gravid during spring and summer. The host fish for the narrow pigtoe is currently unknown (Williams et al. 2008, p. 317). The species is somewhat unusual in that it does tolerate a small reservoir environment (Williams 2009 pers. comm.). Reproducing narrow pigtoe populations were found recently in some areas of Point A Lake and Gantt Lake reservoirs.
The narrow pigtoe is endemic to the Escambia River drainage in Alabama and Florida, and to the Yellow River drainage in Florida (Williams et al. 2008, p. 317)
p. 317). The species is somewhat unusual in that it does tolerate a small reservoir environment (Williams 2009 pers. comm.). Reproducing narrow pigtoe populations were found recently in some areas of Point A Lake and Gantt Lake reservoirs.
The narrow pigtoe is endemic to the Escambia River drainage in Alabama and Florida, and to the Yellow River drainage in Florida (Williams et al. 2008, p. 317). The narrow pigtoe's known historical and current occurrences, by water body and county, are shown in Table 7 below.
Table 7—Known Historical and Current Occurrences for the Narrow Pigtoe Water body Drainage County State Historical or current Bottle Creek Escambia Conecuh AL Historical. Burnt Corn Creek Escambia Conecuh AL Current. Conecuh River Escambia Pike AL Current. Conecuh River Escambia Escambia, Covington, Crenshaw AL Historical and Current. Escambia River Escambia Escambia, Santa Rosa FL Historical and Current. Murder Creek Escambia Conecuh AL Historical. Panther Creek Escambia Butler AL Historical. Patsaliga Creek Escambia Covington, Crenshaw AL Current. Persimmon Creek Escambia Butler AL Current. Three Run Creek Escambia Butler AL Current. Yellow River Yellow Santa Rosa FL Historical. Yellow River Yellow Okaloosa FL Historical and Current. The narrow pigtoe still occurs in much of its historic range, but may be extirpated from localized areas. In the Escambia drainage, the number of locations that support the species has declined from 32 to 24 currently. It was not detected at two historical sites examined recently (four historical sites were not examined) in the drainage. In the Yellow drainage, the number of sites supporting narrow pigtoe populations has declined from four to three currently. The species is rare in the Yellow River drainage; a total of only 23 individuals from 3 locations have been collected since 1995.
Garner et al. (2004, p
It was not detected at two historical sites examined recently (four historical sites were not examined) in the drainage. In the Yellow drainage, the number of sites supporting narrow pigtoe populations has declined from four to three currently. The species is rare in the Yellow River drainage; a total of only 23 individuals from 3 locations have been collected since 1995.
Garner et al. (2004, p. 55) considered the narrow pigtoe vulnerable to extinction because of its limited distribution, rarity, and susceptibility to habitat degradation, and classified it as a species of highest conservation concern in Alabama. Williams et al. (1993, p. 11) considered the narrow pigtoe threatened throughout its range.
Fuzzy Pigtoe
The fuzzy pigtoe ( Pleurobema strodeanum, Wright (1898) is a small to medium-sized mussel known from the Escambia, Yellow, and Choctawhatchee River drainages in Alabama and Florida (Williams et al. 2008, p. 574). The fuzzy pigtoe is oval to subtriangular and reaches about 75 mm (3.0 in.) in length. Its shell surface is usually dark brown to black in color. The shell interior is bluish white, with slight iridescence near the margin (Williams and Butler 1994, p. 90; Williams et al. 2008, p. 573). The fuzzy pigtoe was described by B. H. Wright (1898) as Unio strodeanus. Simpson (1900) reexamined the type specimen and reassigned it to the genus Pleurobema. The uniqueness of the fuzzy pigtoe has been verified by Williams et al. (2008, p. 574).
The fuzzy pigtoe is found in medium creeks and rivers in stable substrates of sand and silty sand with slow to moderate current. The reproductive biology of the fuzzy pigtoe was studied by White et al. (2008, p. 122-123). It is a short-term brooder, with females Cyprinella venusta ) was found to serve as a host for fuzzy pigtoe glochidia in the preliminary study trial.
The fuzzy pigtoe is endemic to the Escambia, Yellow, and Choctawhatchee River drainages in Alabama and Florida (Williams et al. 2008, p. 574)
rate current. The reproductive biology of the fuzzy pigtoe was studied by White et al. (2008, p. 122-123). It is a short-term brooder, with females Cyprinella venusta ) was found to serve as a host for fuzzy pigtoe glochidia in the preliminary study trial.
The fuzzy pigtoe is endemic to the Escambia, Yellow, and Choctawhatchee River drainages in Alabama and Florida (Williams et al. 2008, p. 574). The fuzzy pigtoe's known historical and current occurrences, by water body and county, are shown in Table 8 below.
Table 8—Known Historical and Current Occurrences of the Fuzzy Pigtoe Water body Drainage County State Historical or current Big Sandy Creek Choctawhatchee Bullock AL Current. Blue Creek Choctawhatchee Holmes FL Current. Choctawhatchee River Choctawhatchee Washington, Walton, Holmes, Geneva, Dale FL, AL Historical and Current. Claybank Creek Choctawhatchee Dale AL Current. East Fork Choctawhatchee R. Choctawhatchee Dale AL Current. East Fork Choctawhatchee R. Choctawhatchee Henry AL Historical and Current. East Pittman Creek Choctawhatchee Holmes FL Current. Eightmile Creek Choctawhatchee Walton, Geneva FL, AL Current. Flat Creek Choctawhatchee Geneva AL Current. Holmes Creek Choctawhatchee Holmes, Jackson FL Current. Holmes Creek Choctawhatchee Washington FL Historical and Current. Hurricane Creek Choctawhatchee Geneva AL Current. Judy Creek Choctawhatchee Dale AL Current. Limestone Creek Choctawhatchee Walton FL Historical. Little Choctawhatchee River Choctawhatchee Dale, Houston AL Historical. Panther Creek Choctawhatchee Houston AL Historical. Pauls Creek Choctawhatchee Barbour AL Current. Pea Creek Choctawhatchee Barbour AL Current. Pea River Choctawhatchee Pike, Barbour AL Current. Pea River Choctawhatchee Geneva, Coffee, Dale AL Historical and Current. Sandy Creek Choctawhatchee Walton FL Current. Steep Head Creek Choctawhatchee Coffee AL Current. unnamed trib. to Lindsey Cr. Choctawhatchee Barbour AL Current. Walnut Creek Choctawhatchee Pike AL Current. West Fork Choctawhatchee R
ea Creek Choctawhatchee Barbour AL Current. Pea River Choctawhatchee Pike, Barbour AL Current. Pea River Choctawhatchee Geneva, Coffee, Dale AL Historical and Current. Sandy Creek Choctawhatchee Walton FL Current. Steep Head Creek Choctawhatchee Coffee AL Current. unnamed trib. to Lindsey Cr. Choctawhatchee Barbour AL Current. Walnut Creek Choctawhatchee Pike AL Current. West Fork Choctawhatchee R. Choctawhatchee Dale, Barbour AL Historical and Current. West Pittman Creek Choctawhatchee Holmes FL Current. Wrights Creek Choctawhatchee Holmes FL Historical and Current. Bottle Creek Escambia Conecuh AL Historical and Current. Burnt Corn Creek Escambia Conecuh AL Historical and Current. Conecuh River Escambia Escambia, Covington, Crenshaw, Pike AL Historical and Current. Escambia River Escambia Escambia, Santa Rosa FL Historical and Current. Jordan Creek Escambia Conecuh AL Current. Little Patsaliga Creek Escambia Crenshaw AL Historical and Current. Mill Creek Escambia Pike AL Historical. Murder Creek Escambia Conecuh AL Historical and Current. Patsaliga Creek Escambia Crenshaw AL Historical and Current. Persimmon Creek Escambia Butler AL Current. Pigeon Creek Escambia Covington AL Historical and Current. Sandy Creek Escambia Conecuh AL Historical. Sepulga River Escambia Conecuh AL Historical. Yellow River Yellow Covington AL Historical. Yellow River Yellow Okaloosa FL Historical and Current. Within the Escambia River drainage, the fuzzy pigtoe is historically known from a total of 38 locations. It is currently known from 20 of these locations, however, its status in the Escambia drainage is difficult to assess as 15 of the 18 remaining historical sites have not be surveyed since 1995. The fuzzy pigtoe is exceedingly rare in the Yellow River drainage, where it is known from a total of only five localities. A single individual collected in 2010 in the Florida portion of the main channel is the only recent record of the species in the drainage
ver, its status in the Escambia drainage is difficult to assess as 15 of the 18 remaining historical sites have not be surveyed since 1995. The fuzzy pigtoe is exceedingly rare in the Yellow River drainage, where it is known from a total of only five localities. A single individual collected in 2010 in the Florida portion of the main channel is the only recent record of the species in the drainage. Its range in the Yellow drainage has declined, and the species may no longer occur in the Alabama portions of the drainage. In the Choctawhatchee River drainage, the number of locations that support fuzzy pigtoe populations has declined from 61 to 54. At one site on Limestone Creek, a once abundant population may have disappeared: A total of 56 individuals was collected in 1988; only 3 were collected in 1993 by the same collector; and none were collected during site visits at the same location in 1996 and 2011. Although the species still occurs in much of its historic range in the drainage, it may be extirpated from localized areas.
The fuzzy pigtoe is considered vulnerable to extinction because of its limited distribution and dwindling habitat by Garner et al. (2004, p. 101), who classified it as a species of high conservation concern in Alabama. Williams et al. (1993, p. 11) considered the fuzzy pigtoe a species of special concern throughout its range.
Summary of Factors Affecting the Species
Section 4 of the Act and its implementing regulations at 50 CFR part 424, set forth the procedures for adding species to the Federal List of Endangered and Threatened Wildlife
A. The Present or Threatened Destruction, Modification, or Curtailment of Its Habitat or Range
The habitats of freshwater mussels are vulnerable to water quality degradation and habitat modification from a number of activities associated with modern civilization. The primary cause of the decline of these eight mussels has been the modification and destruction of their stream and river habitat, with sedimentation as the leading cause
on, Modification, or Curtailment of Its Habitat or Range
The habitats of freshwater mussels are vulnerable to water quality degradation and habitat modification from a number of activities associated with modern civilization. The primary cause of the decline of these eight mussels has been the modification and destruction of their stream and river habitat, with sedimentation as the leading cause. Their stream habitats are subject to pollution and alteration from a variety of sources including adjacent land use activities, effluent discharges, and impoundments.
Nonpoint-source pollution from land surface runoff originates from virtually all land use activities and includes sediments, fertilizer, herbicide and pesticide residues; animal wastes; septic tank leakage and gray water discharge; and oils and greases. Current activities and land uses that can negatively affect populations of these eight mussels include unpaved road crossings, improper silviculture and agriculture practices, highway construction, housing developments, pipeline crossings, and cattle grazing. These activities can result in physical disturbance of stream substrates or the riparian zone, excess sedimentation and nutrification, decreased dissolved oxygen concentration, increased acidity and conductivity, and altered flow. Limited range and low numbers make these eight mussels vulnerable to land use changes that would result in increases in nonpoint-source pollution.
Sedimentation is one of the most significant pollution problems for aquatic organisms (Williams and Butler 1994, p. 55), and has been determined to be a major factor in mussel declines (Ellis 1936, pp. 39-40). Impacts resulting from sediments have been noted for many components of aquatic communities
sels vulnerable to land use changes that would result in increases in nonpoint-source pollution.
Sedimentation is one of the most significant pollution problems for aquatic organisms (Williams and Butler 1994, p. 55), and has been determined to be a major factor in mussel declines (Ellis 1936, pp. 39-40). Impacts resulting from sediments have been noted for many components of aquatic communities. For example, sediments have been shown to abrade or suffocate periphyton (organisms attached to underwater surfaces); affect respiration, growth, reproductive success, and behavior of aquatic insects and mussels; and affect fish growth, survival, and reproduction (Waters 1995, pp. 173-175). Heavy sediment loads can destroy mussel habitat, resulting in a corresponding shift in mussel fauna (Brim Box and Mossa 1999, p. 100). Excessive sedimentation can lead to rapid changes in stream channel position, channel shape, and bed elevation (Brim Box and Mossa 1999, p. 102). Sedimentation has also been shown to impair the filter feeding ability of mussels. When in high silt environments, mussels may keep their valves closed more often, resulting in reduced feeding activity (Ellis 1936, p. 30); and high amounts of suspended sediments can dilute their food source (Dennis 1984, p. 212). Increased turbidity from suspended sediment can reduce or eliminate juvenile mussel recruitment (Negus 1966, p. 525; Box and Mossa 1999, pp. 101-102). Many mussel species use visual cues to attract host fishes; such a reproductive strategy depends on clear water. For example, increased turbidity may impact the southern sandshell life cycle by reducing the chance that a sight-feeding host fish will encounter the visual display of its superconglutinate lure (Haag et al. 1995, p. 475; Blalock-Herod et al. 2002, p. 1885). If the superconglutinate is not encountered by a host within a short time period, the glochidia will become nonviable (O'Brien and Brim Box 1999, p. 133)
increased turbidity may impact the southern sandshell life cycle by reducing the chance that a sight-feeding host fish will encounter the visual display of its superconglutinate lure (Haag et al. 1995, p. 475; Blalock-Herod et al. 2002, p. 1885). If the superconglutinate is not encountered by a host within a short time period, the glochidia will become nonviable (O'Brien and Brim Box 1999, p. 133). Also, evidence suggests that conglutinates of the southern kidneyshell, once released from the female mussel, must adhere to hard surfaces in order to be seen by its fish host. If the surface becomes covered in fine sediments, the conglutinate cannot attach and is swept away (Hartfield and Hartfield 1996, p. 373).
Biologists conducting mussel surveys within the drainages have reported observations of excessive sedimentation in the streams and rivers of the three basins. While searching for the Alabama pearlshell in headwater streams of the Conecuh and Alabama drainages, D. N. Shelton (1996, pp. 1-5 in litt.) reported many streams within the study area had experienced heavy siltation, and that all species of mollusks appeared to be adversely affected. M. M. Gangloff (Gangloff and Hartfield 2009, p. 253) observed large amounts of sand and silt in the mainstem Pea and Choctawhatchee rivers during a 2006-2007 survey, and considered this a possible reason for the decline of mussels in the drainage.
In 2009-2010, The Nature Conservancy completed an inventory and prioritization of impaired sites in the Yellow River watershed in Alabama and Florida (Herrington et al., in prep.). The study identified and quantified the impacts of unpaved road crossings and streambank instability and erosion within the river corridor and riparian zone, to assess impairments that could impact the five species occurring in the drainage. A total of 339 unpaved roads and approximately 209 river miles of mainstem and tributaries were assessed using standardized methods
rington et al., in prep.). The study identified and quantified the impacts of unpaved road crossings and streambank instability and erosion within the river corridor and riparian zone, to assess impairments that could impact the five species occurring in the drainage. A total of 339 unpaved roads and approximately 209 river miles of mainstem and tributaries were assessed using standardized methods. Out of these, 409 sites ranked “High” or “Moderate” in risk of excessive sedimentation according to the Sediment Risk Index. Many of the impaired sites (149) were located upstream of known mussel locations. In addition, habitat conditions were characterized at 44 known mussel locations; the sites were scored numerically and rated as poor, fair, good, or excellent. The majority of the mussel sites were assessed to be either fair or poor. Most of these locations were within the vicinity of bridge crossings and boat ramps and several, particularly in the Shoal River in Florida, were directly downstream of highly impaired unpaved road and river corridor sites. In summary, the study found the threat of sedimentation and habitat degradation is high throughout the Yellow River watershed with over 75 percent of sites assessed exhibiting high or moderate risk, and the majority of known mussel locations impaired.
Potential sediment sources within a watershed include virtually any activity that disturbs the land surface. Current sources of sand, silt, and other sediment accumulation in south-central Alabama and western Florida stream channels include unpaved road runoff, agricultural lands, timber harvest, livestock grazing, and construction and other development activities (Williams and Butler 1994, p. 55; Bennett 2002, p. 5 and references therein; Hoehn 1998, pp. 46-47 and references therein). The Choctawhatchee, Pea, and Yellow Rivers Watershed Management Plan (CPYRWMP) and the Conecuh-Sepulga-Blackwater Rivers Watershed Protection Plan (CSBRWPP) document water quality impairments to the Alabama portions of the watersheds
struction and other development activities (Williams and Butler 1994, p. 55; Bennett 2002, p. 5 and references therein; Hoehn 1998, pp. 46-47 and references therein). The Choctawhatchee, Pea, and Yellow Rivers Watershed Management Plan (CPYRWMP) and the Conecuh-Sepulga-Blackwater Rivers Watershed Protection Plan (CSBRWPP) document water quality impairments to the Alabama portions of the watersheds. Both plans identify elevated levels of sediment as one of the primary causes of impairment (CPYRWMP, p. 156; CSBRWPP, p. 110). In the Choctawhatchee and Yellow river drainages, four out of the nine streams in which sediment loads were calculated by the Geological Survey of
Land surface runoff also contributes nutrients (for example, nitrogen and phosphorus from fertilizers, sewage, and animal manure) to rivers and streams, causing them to become eutrophic. Excessive nutrient input stimulates excessive plant growth (algae, periphyton attached algae, and nuisance plants). This enhanced plant growth can cause dense mats of filamentous algae that can expose juvenile mussels to entrainment or predation and be detrimental to the survival of juvenile mussels (Hartfield and Hartfield 1996, p. 373). Excessive plant growth can also reduce dissolved oxygen in the water when dead plant material decomposes. In a review of the effects of eutrophication on mussels, Patzner and Muller (2001, p. 329) noted that stenoecious (narrowly tolerant) species disappear as waters become more eutrophic. They also refer to studies that associate increased levels of nitrate with the decline and absence of juvenile mussels (Patzner and Muller 2001, pp. 330-333). Filamentous algae may also displace certain species of fish, or otherwise affect fish-mussel interactions essential to recruitment (for example, Hartfield and Hartfield 1996, p. 373). Nutrient sources include fertilizers applied to agricultural fields and lawns, septic tanks, and municipal wastewater treatment facilities
cline and absence of juvenile mussels (Patzner and Muller 2001, pp. 330-333). Filamentous algae may also displace certain species of fish, or otherwise affect fish-mussel interactions essential to recruitment (for example, Hartfield and Hartfield 1996, p. 373). Nutrient sources include fertilizers applied to agricultural fields and lawns, septic tanks, and municipal wastewater treatment facilities.
Because of their sedentary characteristics, mussels are extremely vulnerable to toxic effluents (Sheehan et al. 1989, pp. 139-140; Goudreau et al. 1993, pp. 216-227; Newton 2003, p. 2543). Descriptions of localized mortality have been provided for chemical spills and other discrete point-source discharges; however, rangewide decreases in mussel density and diversity may result from the more insidious effects of chronic, low-level contamination (Newton 2003, p. 2543, Newton et al. 2003, p. 2554). Freshwater mussel experts often report chemical contaminants as factors limiting to unionids (Richter et al. 1997, pp. 1081-1093). They note high sensitivity of early life stages to contaminants such as chlorine (Wang et al. 2007 pp. 2039-2046), metals (Keller and Zam 1991, p. 542; Jacobson et al. 1993, pp. 879-883), ammonia (Augspurger et al. 2003, pp. 2571-2574; Wang et al. 2007 pp. 2039-2046), and pesticides (Bringolf et al. 2007a,b pp. 2089-2092, pp. 2096-2099). Pesticide residues from agricultural, residential, or silvicultural activities enter streams mainly by surface runoff. Agricultural crops locally grown within the range of these mussels associated with high pesticide use include cotton, peanuts, corn, and soybeans. Chlorine, metals, and ammonia are common constituents in treated effluent from municipal and industrial wastewater treatment facilities. A total of 62 municipal and 39 industrial wastewater treatment facilities are permitted in Alabama and Florida to discharge treated effluent into surface waters of the three river drainages (FDEP 2010b; ADEM 2010c)
use include cotton, peanuts, corn, and soybeans. Chlorine, metals, and ammonia are common constituents in treated effluent from municipal and industrial wastewater treatment facilities. A total of 62 municipal and 39 industrial wastewater treatment facilities are permitted in Alabama and Florida to discharge treated effluent into surface waters of the three river drainages (FDEP 2010b; ADEM 2010c).
States maintain water-use classifications through issuance of National Pollutant Discharge Elimination System (NPDES) permits to industries, municipalities, and others that set maximum limits on certain pollutants or pollutant parameters. The Alabama Department of Environmental Management (ADEM) has designated the water use classification for most portions of the Escambia, Yellow, and Choctawhatchee Rivers as “Fish and Wildlife” (F&W), and a few portions (mostly lakes) as “Swimming” (S). The F&W designation establishes minimum water quality standards that are believed to protect existing species and water uses like fishing and recreation within the designated area, while the S classification establishes higher water quality standards that are protective of human contact with the water. The Florida Department of Environmental Protection (FDEP) classifies all three river drainages as Class III waters. The Class III designation establishes minimum water quality standards that are believed to protect species and uses such as recreation. The Choctawhatchee and Shoal Rivers are also designated as Outstanding Florida Waters (OFW) by the State of Florida. The designation prevents the discharge of pollutants, which would lower existing water quality or significantly degrade the OFW.
Section 303(d) of the Clean Water Act requires States to identify waters that do not fully support their designated use classification. These impaired water bodies are placed on the State's 303(d) list, and a total maximum daily load (TMDL) must be developed for the pollutant of concern
events the discharge of pollutants, which would lower existing water quality or significantly degrade the OFW.
Section 303(d) of the Clean Water Act requires States to identify waters that do not fully support their designated use classification. These impaired water bodies are placed on the State's 303(d) list, and a total maximum daily load (TMDL) must be developed for the pollutant of concern. A TMDL is an estimate of the total load of pollutants that a segment of water can receive without exceeding applicable water quality criteria. Alabama's 303(d) list identifies a total of 25 impaired stream segments within the Escambia, Yellow, and Choctawhatchee River basins that either support populations of the eight species or that flow into streams that support them. The list identifies metals (mercury and lead), organic enrichment, pathogens, siltation, excess nutrients, or unknown toxicity as reasons for impairment (ADEM 2010a, pp. 4-8). Various potential point and non-point pollution sources are identified, such as atmospheric deposition, pasture grazing, feedlots, municipal, industrial, urban runoff, agriculture, and land development. Florida's 303(d) list identifies a total of 22 impaired stream segments within the basins that either support populations of seven of the species (the Alabama pearlshell does not occur in Florida) or that flow into streams that support them. The list identifies coliform bacteria, low dissolved oxygen (nutrients), and mercury (in fish tissue) as reasons for inclusion (FDEP 2010a, pp. 4-6).
While the negative effects of point-source discharges on aquatic communities in Alabama and Florida have been reduced over time by compliance with State and Federal regulations pertaining to water quality, there has been less success in dealing with nonpoint-source pollution impacts
ia, low dissolved oxygen (nutrients), and mercury (in fish tissue) as reasons for inclusion (FDEP 2010a, pp. 4-6).
While the negative effects of point-source discharges on aquatic communities in Alabama and Florida have been reduced over time by compliance with State and Federal regulations pertaining to water quality, there has been less success in dealing with nonpoint-source pollution impacts. Because these contaminant sources stem from urban surface runoff, private landowner activities (construction, grazing, agriculture, silviculture), and public construction works (bridge and highway construction and maintenance), they are often more difficult to regulate.
The damming of rivers has been a major factor contributing to the demise of freshwater mussels (Bogan 1993, p. 604). Dams eliminate or reduce river flow within impounded areas, trap silts and cause sediment deposition, alter water temperature and dissolved oxygen levels, change downstream water flow and quality, affect normal flood patterns, and block upstream and downstream movement of mussels and their host fishes (Bogan 1993, p. 604; Vaughn and Taylor 1999, pp. 915-917; Watters 1999, pp. 261-264; McAllister et al. 2000, p. iii; Marcinek et al. 2005, pp. 20-21). Below dams, mollusk declines are associated with changes and fluctuation in flow regime, scouring and erosion, reduced dissolved oxygen et al. 1993, p. 7; Neves et al. 1997, pp. 63-64; Watters 1999, pp. 261-264; Marcinek et al. 2005, pp. 20-21). Because rivers are linear systems, these alterations can cause mussel declines for many miles below the dam (Vaughn and Taylor 1999, p. 916).
Three significant mainstem impoundments are situated within the three drainages, all in Alabama. Constructed in 1923 for hydroelectric power generation, Point A Lake and Gantt Lake dams are located on the mainstem of the Conecuh River in Covington County, AL. Combined, these two dams impound approximately 3,400 acres at normal pool
s for many miles below the dam (Vaughn and Taylor 1999, p. 916).
Three significant mainstem impoundments are situated within the three drainages, all in Alabama. Constructed in 1923 for hydroelectric power generation, Point A Lake and Gantt Lake dams are located on the mainstem of the Conecuh River in Covington County, AL. Combined, these two dams impound approximately 3,400 acres at normal pool. Both impoundments have limited storage capacity and are operated as modified run-of-river projects with daily peaking. For example, when inflows to Gantt are greater than 1,500 cubic feet per second (cfs), the outflow matches the inflow at Point A. However, during the summer months, when inflows can fall below 1,500 cfs, a portion of the inflow may be stored and released when power generation is in high demand. Regardless of the inflow, Point A Dam has a minimum continuous discharge requirement of 500 cfs and a requirement to meet a dissolved oxygen level of no less than 4.0 milligram per liter (mg/l).
The Elba Dam on the Pea River mainstem in Alabama was constructed in 1903 for power generation, but is no longer in use. The dam does not store water, so outflow basically equals inflow. The Elba Dam does not have a reservoir, only a widened channel, which is roughly one and a half to two times wider above the dam than below. Channel scour (deepening of the streambed as a result of erosion) is occurring downstream of the Elba Dam (Williams 2010 pers. comm.). All three dams are barriers to fish migration and to the movement of mussel host species. By blocking fish movement, the dams prevent gene exchange between upstream and downstream mussel populations. The three dams currently separate populations of southern sandshell, southern kidneyshell, Choctaw bean, tapered pigtoe, and fuzzy pigtoe. In addition, two smaller impoundments are located on tributary streams
various forms of pollution and impoundments is a significant threat to the continued existence of these eight species. Degradation from sedimentation and contaminants threatens the habitat and water quality necessary to support these species throughout their entire range. Sedimentation can cause mortality by suffocation, impair the ability to feed, respire, and reproduce; and destabilize substrate. Contaminants associated with municipal and industrial effluents (metals, ammonia, chlorine) and with agriculture and silviculture (pesticides) are lethal to mussels particularly to the highly sensitive early life stages. The effects of impoundments are more discreet, but can cause severe alternations to mussel habitat both upstream and downstream of the dam, and can impair dispersal and breeding ability. While recent surveys for these species have documented several new populations, they have also documented a decline in (and the loss of) many of the known populations due to human impact. Therefore, we have determined that the present or threatened destruction, modification, or curtailment of habitat and range is a threat of high magnitude to the Alabama pearlshell, round ebonyshell, southern kidneyshell, southern sandshell, and Choctaw bean; and a threat of moderate magnitude to the tapered pigtoe, narrow pigtoe, and fuzzy pigtoe. This threat is current (as evidenced by population declines) and is projected to continue and increase into the future with additional anthropogenic pressures.
B. Overutilization for Commercial, Recreational, Scientific, or Educational Purposes
None of the eight mussels are commercially valuable species, and the streams and rivers that they inhabit are not subject to harvesting activities for commercial mussel species. Although the eight species have been taken for scientific and private collections in the past, collecting is not considered a factor in the decline of these species
cial, Recreational, Scientific, or Educational Purposes
None of the eight mussels are commercially valuable species, and the streams and rivers that they inhabit are not subject to harvesting activities for commercial mussel species. Although the eight species have been taken for scientific and private collections in the past, collecting is not considered a factor in the decline of these species. Such activity may increase as their rarity becomes known; however, we have no specific information indicating that overcollection is currently a threat. Therefore, we find that overutilization for commercial, recreational, scientific, or educational purposes is not a threat to the eight mussels at this time.
C. Disease or Predation
Diseases of freshwater mussels are poorly known, and we have no specific information indicating that disease poses a threat to populations of these eight species. Juvenile and adult mussels are prey items for some invertebrate predators and parasites (for example, nematodes and mites), and provide prey for a few vertebrate species (for example, raccoons, muskrats, otters, and turtles) (Hart and Fuller 1974, pp. 225-240). However, we have no evidence of any specific declines in these species due to predation. Therefore, diseases and predation of freshwater mussels remain largely unstudied and are not considered a threat to the eight mussels at this time.
D. The Inadequacy of Existing Regulatory Mechanisms
There is no information on the sensitivity of the Alabama pearlshell, round ebonyshell, southern kidneyshell, southern sandshell, Choctaw bean, tapered pigtoe, narrow pigtoe, or fuzzy pigtoe to aquatic pollutants. Current State and Federal regulations regarding pollutants are designed to be protective of aquatic organisms; however, freshwater mussels may be more susceptible to some pollutants than test organisms commonly used in bioassay tests. A multitude of bioassay tests conducted on 16 mussel species (summarized by Augspurger et al. 2007, pp
pigtoe, narrow pigtoe, or fuzzy pigtoe to aquatic pollutants. Current State and Federal regulations regarding pollutants are designed to be protective of aquatic organisms; however, freshwater mussels may be more susceptible to some pollutants than test organisms commonly used in bioassay tests. A multitude of bioassay tests conducted on 16 mussel species (summarized by Augspurger et al. 2007, pp. 2025-2028), show that freshwater mussels are more sensitive than previously known to some chemical contaminants including chlorine, ammonia, copper, the pesticides chlorothalonil and glyphosate, and the surfactant MON 0818. For example, several recent studies have demonstrated that U.S. Environmental Protection Agency (EPA) criteria for ammonia may not be protective of freshwater mussels (Augspurger et al. 2003, p. 2571; Newton et al. 2003, pp. 2559-2560; Mummert et al. 2003, pp. 2548-2552).
Ammonia is an important aquatic pollutant because of its relatively high toxicity and common occurrence in et al. 2007, p. 2026). Elevated copper in surface waters can result from natural runoff sources, but is more often associated with a private or municipal wastewater effluent. Pesticide residues enter streams from agricultural, residential, or silvicultural runoff. Environmental chlorine concentrations will most often be associated with a point source discharge such as a municipal wastewater treatment facility.
As indicated in the Factor A discussion above, sedimentation is considered the most significant threat to these eight species. Best Management Practices (BMPs) for sediment and erosion control are often recommended or required for construction projects, however, compliance, monitoring, and enforcement of these recommendations are often poorly implemented. Although unpaved roads likely contribute the majority of sediment to the river basins, other sources including forestry, row crops, and construction contribute to the total sediment load
ractices (BMPs) for sediment and erosion control are often recommended or required for construction projects, however, compliance, monitoring, and enforcement of these recommendations are often poorly implemented. Although unpaved roads likely contribute the majority of sediment to the river basins, other sources including forestry, row crops, and construction contribute to the total sediment load.
States are required under the Clean Water Act to establish a TMDL for the pollutants of concern that the water body can receive without exceeding the applicable standard (see discussion under Factor A). However, the Federal Clean Water Act is not fully utilized in the protection of these river systems. For example, of the 51 impaired water bodies identified within the drainages, less than one-fourth currently have approved TMDLs (ADEM 2010b, pp. 3-6; FDEP 2010a, pp. 4-6).
In summary, some regulatory mechanisms exist that protect aquatic species, however, these regulations are not effective at protecting mussels and their habitats from sedimentation and contaminants. This is apparent from the decline in all eight mussels. Pollution from non-point sources is the greatest threat to these eight mussels (see Factor A discussion); however, this type of pollution is difficult to regulate and not effectively controlled by State and Federal water quality regulations within the proposed designation. Therefore, we find current existing regulatory mechanisms are inadequate to protect the eight mussels throughout their ranges. This threat is current and is projected to continue into the future.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Random Catastrophic Events
The Gulf coastal region is prone to extreme hydrologic events. Extended droughts result from persistent high-pressure systems, which inhibit moisture from the Gulf of Mexico from reaching the region (Jeffcoat et al. 1991, p. 163-170)
threat is current and is projected to continue into the future.
E. Other Natural or Manmade Factors Affecting Its Continued Existence
Random Catastrophic Events
The Gulf coastal region is prone to extreme hydrologic events. Extended droughts result from persistent high-pressure systems, which inhibit moisture from the Gulf of Mexico from reaching the region (Jeffcoat et al. 1991, p. 163-170). Warm, humid air from the Gulf of Mexico can produce strong frontal systems and tropical storms resulting in heavy rainfall and extensive flooding (Jeffcoat et al. 1991, p. 163-170). Although floods and droughts are a natural part of the hydrologic processes that occur in these river systems, these events may contribute to the further decline of mussel populations suffering the effects of other threats.
During high flows, flood scour can dislodge mussels where they may be injured, buried, swept into unsuitable habitats, or stranded and perish when flood waters recede (Vannote and Minshall 1982, p. 4105; Tucker 1996, p. 435; Hastie et al. 2001, pp. 107-115; Peterson et al. 2011, unpaginated). Heavy spring rains in 2009 resulted in severe flooding in the basins that destroyed numerous stream crossings.
During drought, stream channels may become disconnected pools where mussels are exposed to higher water temperatures, lower dissolved oxygen levels, and predators; or channels may become dewatered entirely. Johnson et al. (2001, p. 6) monitored mussel responses during a severe drought in 2000 in tributaries of the Lower Flint River in Georgia, and found that most mortality occurred when dissolved oxygen levels dropped below 5 mg/L. Furthermore, increased human demand and competition for surface and ground water resources for irrigation and consumption during drought can cause drastic reductions in stream flows and alterations to hydrology (Golladay et al. 2004, p. 504; Golladay et al. 2007 unpaginated). Extended droughts occurred in the Southeast during 1998 to 2002 and again in 2006 to 2008
ygen levels dropped below 5 mg/L. Furthermore, increased human demand and competition for surface and ground water resources for irrigation and consumption during drought can cause drastic reductions in stream flows and alterations to hydrology (Golladay et al. 2004, p. 504; Golladay et al. 2007 unpaginated). Extended droughts occurred in the Southeast during 1998 to 2002 and again in 2006 to 2008. The effects of these recent droughts on these eight mussels are unknown; however, substantial declines in mussel diversity and abundance as a direct result of drought have been documented in southeastern streams (for example, Golladay et al. 2004, pp. 494-503; Haag and Warren 2008, p. 1165). The Alabama pearlshell is particularly at risk during drought as its headwater stream habitats are vulnerable to dewatering. Shelton (1995, p. 4 unpub. data) reported one of the most common causes of mortality in the species is due to stranding by extreme low water.
There is a growing concern that climate change may lead to increased frequency of severe storms and droughts (McLaughlin et al. 2002, p. 6074; Golladay et al. 2004, p. 504; Cook et al. 2004, p. 1015). Specific effects of climate change to mussels, their habitat, and their fish hosts could include changes in stream temperature regimes, the timing and levels of precipitation causing more frequent and severe floods and droughts, and alien species introductions. Increases in temperature and reductions in flow may also lower dissolved oxygen levels in interstitial habitats which can be lethal to juveniles (Sparks and Strayer 1998, pp. 131-133). Effects to mussel populations from these environmental changes could include reduced abundance and biomass, altered species composition, and host fish considerations (Galbraith et al. 2010, pp. 1180-1182). The present conservation status, complex life histories, and specific habitat requirements of freshwater mussels suggest that they may be quite sensitive to climate change (Hastie et al. 2003, p. 45)
ts to mussel populations from these environmental changes could include reduced abundance and biomass, altered species composition, and host fish considerations (Galbraith et al. 2010, pp. 1180-1182). The present conservation status, complex life histories, and specific habitat requirements of freshwater mussels suggest that they may be quite sensitive to climate change (Hastie et al. 2003, p. 45).
The linear nature of their habitat, reduced range, and small population sizes make these eight mussels vulnerable to contaminant spills. Spills as a result of transportation accidents are a constant, potential threat as numerous highways and railroads cross the stream channels of the basins. Also, more than 400 oil wells are located within Conecuh and Escambia Counties, Alabama. In Conecuh County, most of these wells are concentrated in the Cedar Creek drainage, which supports at least two populations of the Alabama pearlshell. These wells are subject to periodic spills either directly at the well site or associated with the transport of the oil. For example, on February 5, 2010, an oil spill occurred in the headwaters of Feagin Creek. Feagin Creek is located between two known pearlshell locations, Little Cedar and Amos Mill Creeks. The resulting spill discharged more than 150 gallons of oil into Feagin Creek. Although there were no known populations of the pearlshell in Feagin Creek, this type of spill could have easily occurred in one of the adjacent watersheds that supports the pearlshell. Since 2000, there have been 13 spills reported in Conecuh, 36 in Escambia, and 33 in Covington Counties, Alabama.
Reduced Genetic Diversity
Population fragmentation and isolation prohibits the natural interchange of genetic material between
Host Fish Considerations
As mentioned in the General Biology section above, all of these eight species require a fish host in order to complete their life cycle
0, there have been 13 spills reported in Conecuh, 36 in Escambia, and 33 in Covington Counties, Alabama.
Reduced Genetic Diversity
Population fragmentation and isolation prohibits the natural interchange of genetic material between
Host Fish Considerations
As mentioned in the General Biology section above, all of these eight species require a fish host in order to complete their life cycle. Therefore, these mussels would be adversely affected by the loss or reduction of fish species essential to their parasitic glochidial stage. The blacktail shiner ( Cyprinella venusta ), a common and abundant fish species, was found to serve as a glochidial host for the tapered pigtoe and fuzzy pigtoe (White et al. 2008, p. 123). The specific hosts for the Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, Choctaw bean, and narrow pigtoe have not been identified, however, other species of the same genera are known to parasitize cyprinids (minnows), centrachids (sunfish), and percids (darters) (Haag and Warren 1997, pp. 580-581, 583; Keller and Ruessler 1997, p. 405; O'Brien and Brim Box 1999, p. 134; Haag et al. 1999, p. 150; Haag and Warren 2003, pp. 81-82; Luo 1993, p. 16).
Nonindigenous Species
The Asian clam ( Corbicula fluminea ) has been introduced to the drainages and may be adversely affecting these eight mussels through direct competition for space and resources. The Asian clam was first detected in eastern Gulf drainages in the early 1960s, and is presently wide-spread throughout the Escambia, Yellow, and Choctawhatchee River drainages (Heard 1975, p. 2). The invasion of the Asian clam in these and in other eastern Gulf drainages has been accompanied by drastic declines in populations of native mussels (see observations by Heard 1975, p. 2; and Shelton 1995, p. 4 unpub. data). However, it is difficult to say whether the Asian clam competitively excluded the native mussels, or if it was simply tolerant of whatever caused the mussels to disappear
2). The invasion of the Asian clam in these and in other eastern Gulf drainages has been accompanied by drastic declines in populations of native mussels (see observations by Heard 1975, p. 2; and Shelton 1995, p. 4 unpub. data). However, it is difficult to say whether the Asian clam competitively excluded the native mussels, or if it was simply tolerant of whatever caused the mussels to disappear. The Asian clam may pose a direct threat to native mussels, particularly as juveniles, as a competitor for resources such as food, nutrients, and space (Neves and Widlak 1987, p. 6). Dense populations of Asian clams may ingest large numbers of unionid sperm, glochidia, and newly metamorphosed juveniles, and may actively disturb sediments, reducing habitable space for juvenile native mussels, or displacing them downstream (Strayer 1999, p. 82; Yeager et al. 2000, pp. 255-256).
The flathead catfish ( Pylodictis olivaris ) has been introduced to the drainages and may be adversely impacting native fish populations. The flathead catfish is a large predator native to the central United States, and since its introduction outside its native range has altered the composition of native fish populations through predation (Boschung and Mayden 2004, p. 350). Diet and selectivity studies of introduced flathead catfish in coastal North Carolina river systems show it feeds primarily on other fish species (Guier et al. 1984, pp. 617-620; Pine et al. 2005, p. 909). The flathead catfish is now well-established in the Escambia, Yellow, and Choctawhatchee River drainages, and its numbers appear to be growing (Strickland 2010 pers. comm.). Biologists working in the Florida portions of these drainages have observed a correlation between the increase in flathead catfish numbers and a decrease in numbers of other native fish species, particularly of bullhead catfish ( Ameiurus sp.) and redbreast sunfish ( Lepomis auritus ) (Strickland 2010 pers. comm.)
River drainages, and its numbers appear to be growing (Strickland 2010 pers. comm.). Biologists working in the Florida portions of these drainages have observed a correlation between the increase in flathead catfish numbers and a decrease in numbers of other native fish species, particularly of bullhead catfish ( Ameiurus sp.) and redbreast sunfish ( Lepomis auritus ) (Strickland 2010 pers. comm.). Although we do not know the specific fish hosts for six of the mussel species, the loss or reduction of native fishes in general could affect their ability to recruit.
In summary, a variety of natural or manmade factors currently threaten these eight mussels. Stochastic events such as droughts and floods have occurred in these three river drainages in the past, and climate change may increase the frequency and intensity of similar events in the future. The withdrawal of surface and ground waters during drought can cause further drastic flow reductions and alterations that may cause declines in mussel abundance and distribution. Contaminant spills have also occurred in these drainages and currently are a threat, particularly in the Alabama portions of the Escambia River drainage where there are numerous oil wells. It is not known if these species are currently experiencing a loss of genetic viability; however, their restricted or reduced ranges, fragmented habitats, and small population sizes increases the risks and consequences of inbreeding depression and loss of genetic variation. Introduced species, such as the Asian clam, may adversely impact these mussels through direct competition for resources. Another introduced species, the flathead catfish, may consume host fishes, thereby affecting mussel recruitment
tricted or reduced ranges, fragmented habitats, and small population sizes increases the risks and consequences of inbreeding depression and loss of genetic variation. Introduced species, such as the Asian clam, may adversely impact these mussels through direct competition for resources. Another introduced species, the flathead catfish, may consume host fishes, thereby affecting mussel recruitment. Therefore, we have determined that other natural or manmade factors, specifically threats from flooding, drought, and contaminant spills, are high in magnitude to the Alabama pearlshell, round ebonyshell, southern kidneyshell, southern sandshell, and Choctaw bean; and are moderate in magnitude to the tapered pigtoe, narrow pigtoe, and fuzzy pigtoe. These threats are currently impacting these species and are projected to continue or increase in the future. We have determined that threats from the Asian clam are moderate in magnitude to the Alabama pearlshell, round ebonyshell, southern kidneyshell, southern sandshell, and Choctaw bean; and are low in magnitude to the tapered pigtoe, narrow pigtoe, and fuzzy pigtoe. We have determined that reduced genetic diversity, the absence or reduction of fish hosts, and the presence of flathead catfish have the potential to adversely impact the eight mussels, however, we do not know the magnitude of these threats at this time.
Proposed Determination
We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats to the Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, Choctaw bean, tapered pigtoe, narrow pigtoe, and fuzzy pigtoe
pact the eight mussels, however, we do not know the magnitude of these threats at this time.
Proposed Determination
We have carefully assessed the best scientific and commercial information available regarding the past, present, and future threats to the Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, Choctaw bean, tapered pigtoe, narrow pigtoe, and fuzzy pigtoe. Section 3(6) of the Act defines an endangered species as “any species which is in danger of extinction throughout all or a significant portion of its range,” and defines a threatened species as “any species which is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range.” As described in detail above, these eight species are currently at risk throughout all of their respective ranges due to ongoing threats of habitat destruction and modification (Factor A), inadequacy of existing regulatory mechanisms (Factor D), and other natural or manmade factors affecting their continued existence (Factor E). Specifically, these factors include sedimentation, municipal and industrial
Species with small ranges, few populations, and small or declining population sizes, are the most vulnerable to extinction (Primack 2008, p. 137). The effects of certain factors, particularly habitat degradation and loss, catastrophic events, and introduced species, increase in magnitude when population size is small (Soulé 1987, pp. 33, 71; Primack 2008, pp. 133-135, 152). We believe the impact of habitat degradation, catastrophic events, and introduced species are more severe (magnitude is higher) to the Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, and Choctaw bean, which have few populations coupled with low numbers of individuals and/or very limited ranges, than they are to the tapered pigtoe, narrow pigtoe, and fuzzy pigtoe which have declining and fragmented populations and limited ranges
ts, and introduced species are more severe (magnitude is higher) to the Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, and Choctaw bean, which have few populations coupled with low numbers of individuals and/or very limited ranges, than they are to the tapered pigtoe, narrow pigtoe, and fuzzy pigtoe which have declining and fragmented populations and limited ranges. We believe that, when combining the effects of historical, current, and future habitat loss and degradation, historical and ongoing drought, and the exacerbating effects of small and declining population sizes and curtailed ranges, the Alabama pearlshell, round ebonyshell, southern sandshell, southern kidneyshell, and Choctaw bean are in danger of extinction throughout all of their ranges; and the tapered pigtoe, narrow pigtoe, and fuzzy pigtoe are threatened to become endangered within the foreseeable future throughout all of their ranges. In addition, any factor ( i.e., habitat loss or natural and manmade factors) that results in a further decline in habitat or individuals may be problematic for the long-term recovery of these species.
Therefore, based on the best available scientific and commercial information, we propose to list the Alabama pearlshell, round ebonyshell, southern kidneyshell, southern sandshell, and Choctaw bean as endangered species throughout all of their ranges; and we propose to list the tapered pigtoe, narrow pigtoe, and fuzzy pigtoe as threatened species throughout all of their ranges. Furthermore, we examined each of the five species proposed for endangered status and each of the three species proposed for threatened status to analyze if any significant portions of their ranges may warrant a different status. However, because of their limited and curtailed ranges, and uniformity of the threats throughout their entire respective, we find there are no significant portions of any of the species' ranges that may warrant a different determination of status
tatus and each of the three species proposed for threatened status to analyze if any significant portions of their ranges may warrant a different status. However, because of their limited and curtailed ranges, and uniformity of the threats throughout their entire respective, we find there are no significant portions of any of the species' ranges that may warrant a different determination of status.
Available Conservation Measures
Conservation measures provided to species listed as endangered or threatened under the Act include recognition, recovery actions, requirements for Federal protection, and prohibitions against certain practices. Recognition through listing results in public awareness and conservation by Federal, State, and local agencies, private organizations, and individuals. The Act encourages cooperation with the States and requires that recovery actions be carried out for all listed species. The protection measures required of Federal agencies and the prohibitions against certain activities involving listed wildlife are discussed in Effects of Critical Habitat Designation and are further discussed, in part, below.
Section 7(a) of the Act requires Federal agencies to evaluate their actions with respect to any species that is proposed or listed as endangered or threatened and with respect to its critical habitat, if any is designated. Regulations implementing this interagency cooperation provision of the Act are codified at 50 CFR part 402. Section 7(a)(4) of the Act requires Federal agencies to confer with the Service on any action that is likely to jeopardize the continued existence of a species proposed for listing or result in destruction or adverse modification of proposed critical habitat. If a species is listed subsequently, section 7(a)(2) of the Act requires Federal agencies to ensure that activities they authorize, fund, or carry out are not likely to jeopardize the continued existence of the species or destroy or adversely modify its critical habitat
tinued existence of a species proposed for listing or result in destruction or adverse modification of proposed critical habitat. If a species is listed subsequently, section 7(a)(2) of the Act requires Federal agencies to ensure that activities they authorize, fund, or carry out are not likely to jeopardize the continued existence of the species or destroy or adversely modify its critical habitat. If a Federal action may affect a listed species or its critical habitat, the responsible Federal agency must enter into formal consultation with the Service.
Federal agency actions that may affect the eight mussel species include, but are not limited to: the management of and any other landscape altering activities on Federal lands administered by the Department of Defense and U.S. Forest Service; issuance of section 404 Clean Water Act permits by the Army Corps of Engineers; licensing of hydroelectric dams, and construction and management of gas pipeline and power line rights-of-way approved by the Federal Energy Regulatory Commission; construction and maintenance of roads or highways funded by the Federal Highway Administration; and land management practices administered by the Department of Agriculture. It has been the experience of the Service from consultations on other species, however, that nearly all section 7 consultations have been resolved so that the species have been protected and the project objectives have been met.
The Act and its implementing regulations set forth a series of general prohibitions and exceptions that appl

[Text truncated at 120,000 characters. The full text is on the page linked above.]

## Nearby sections

- [76 FR 78 Federal Motor Vehicle Safety Standard; Engine Control Module Speed Limiter Device](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2010-33057.md)
- [76 FR 291 Special Conditions: Gulfstream Model GVI Airplane; Single-Occupant Side-Facing Seats](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2010-33221.md)
- [76 FR 718 General Administrative Regulations; Good-Performance Refunds](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-14.md)
- [76 FR 721 Airworthiness Directives; Gulfstream Aerospace Corporation Model G-1159 Airplanes](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-54.md)
- [76 FR 752 Approval and Promulgation of Implementation Plans; Connecticut: Prevention of Significant Deterioration; Greenhouse Gas Permitting Authority and Tailoring Rule Revision](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-17.md)
- [76 FR 766 Amtrak Emergency Routing Orders](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2010-33284.md)
- [76 FR 1389 Outer Continental Shelf Air Regulations Consistency Update for California](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-242.md)
- [76 FR 2070 Approval and Promulgation of Air Quality Implementation Plans; Virginia; Prevention of Significant Deterioration; Greenhouse Gas Permitting Authority and Tailoring Rule Revision](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-495.md)
- [76 FR 2268 Viruses, Serums, Toxins, and Analogous Products; Packaging and Labeling](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-648.md)
- [76 FR 2281 Airworthiness Directives; BAE SYSTEMS (OPERATIONS) LIMITED Model BAe 146 Airplanes, and Model Avro 146-RJ Airplanes](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-585.md)
- [76 FR 2297 Framework for Next Generation 911 Deployment](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-565.md)
- [76 FR 2609 Proposed Amendment of Class E Airspace; Pueblo, CO](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-812.md)
- [76 FR 2842 Airworthiness Directives; Eurocopter France (Eurocopter) Model SA-365N, SA-365N1, AS-365N2, AS 365 N3, and SA-366G1 Helicopters](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-720.md)
- [76 FR 2848 Airworthiness Directives; The Boeing Company Model 757 Airplanes](https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-879.md)

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/FR_PRORULE_2011-24519. Check the current official text before relying on it. Not legal advice.