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Seven small brownish-yellow mussels held in open hands by a biologist.
Information icon Atlantic pigtoes ready for release. Photo by USFWS.

Atlantic pigtoe mussel listing proposal and critical habitat designation

What actions are being taken by the U.S. Fish and Wildlife Service?

The Service is proposing three actions:

  1. Protecting the Atlantic pigtoe, a freshwater mussel native to rivers of the Atlantic seaboard, as threatened under the Endangered Species Act (ESA).
  2. Designating 539 river miles of critical habitat across 16 units.
  3. Implementing a special regulation known as a 4(d) rule, that would streamline and exempt from the regulatory process certain management actions that benefit the mussel.

Why is the Service proposing to list the Atlantic pigtoe as threatened?

The downward trend of the mussel’s population health is compromising its ability to respond to disturbances. A Species Status Assessment report confirms that the Atlantic pigtoe could face extinction in the foreseeable future unless the Service and its partners are able to collaborate to conserve and bring back this mussel. Experts compared occurrences across the landscape over time and found that the Atlantic pigtoe has lost 60 percent of its historical range.

What is the difference between threatened and endangered species?

The ESA describes two categories of declining plants and wildlife that need protection: endangered and threatened. Under the ESA, “endangered” means an animal or plant is currently in danger of becoming extinct throughout all or a significant portion of its range; “threatened” means it is likely to become endangered in the foreseeable future.

After careful examination of the best available scientific information about the Atlantic pigtoe’s past, current and future conditions, the Service determined that the freshwater mussel meets the ESA’s definition of threatened.

All of the ESA’s protections are provided to endangered species. Many, but not all, of those protections are available to threatened fish and wildlife. Threatened status provides the Service and state agencies increased flexibility when managing a species and issuing permits to “take” (kill, wound, trap or move as defined by the ESA) a protected species. The Service may issue permits to take individuals for

  1. scientific purposes,
  2. enhancing its propagation or survival, or
  3. incidental taking, when done under the provisions of a Service-approved habitat conservation plan,
  4. zoological exhibition,
  5. educational purposes, or
  6. special purposes consistent with the purposes of the ESA.

Section 4(d) of the ESA allows the Service to implement special regulations that tailor the take protections for threatened species, if special regulations are necessary and advisable to conserve the species. Such special regulations cannot be developed for endangered species.

What is the Atlantic pigtoe?

The Atlantic pigtoe is a freshwater mussel/clam native to the Atlantic Slope drainage in Virginia, North Carolina, South Carolina, and Georgia. The shell of the Atlantic pigtoe is a rounded square shape with a distinct posterior ridge. The outer surface of the shell is tan to dark brown and parchment-like, while the inner layer is iridescent blue to salmon, white or orange. Although larger specimens exist, the Atlantic pigtoe rarely exceeds two inches in length.

Where is the Atlantic pigtoe found?

The Atlantic pigtoe is found in seven of the 12 river basins the mussel used to occupy. The current distribution includes the James, Chowan, Roanoke, Tar, Neuse, Cape Fear and the Yadkin-Pee Dee river basins. Records do not show the Atlantic pigtoe within the last 20 years in the Catawba, Edisto, Savannah, Ogeechee and Altamaha river basins.

The Atlantic pigtoe primarily burrows in coarse sand and gravel that it needs for breeding, feeding and sheltering. Historically, the best populations existed in small creeks to larger rivers with excellent water quality, where flows are sufficient to maintain clean, silt-free substrates.

What are the threats/stressors to the Atlantic pigtoe?

The mussel can be found in stable, silt-free and detritus-free sand and gravel bars, and it depends on clean, moderate flowing water with high dissolved oxygen. Threats include:

Fragmented habitat

Dams or culverts limit a mussel’s ability to distribute throughout a stream to occupy quality habitat. Impoundments slow down water and limit the amount of dissolved oxygen, thus making unsuitable living conditions.


Paved roads, parking lots, roofs and highly compacted soils like sports fields prevent the natural soaking of rainwater into the ground and slow seeping into streams and alter streams in the following ways:

Increased water quantity

Storm drains deliver large volumes of water to streams much faster than would occur naturally resulting in flooding and bank erosion. Species living in the streams become stressed, displaced or killed by the fast-moving water and debris and sediment carried in it.

Decreased water quality

Pollutants (wastewater discharges, gasoline or oil drips, fertilizers, etc.) accumulate on impervious surfaces and are washed directly into the streams.

Increased water temperature

During warm weather, rain that falls on impervious surfaces becomes superheated and when it enters streams and can stress or kill species living in the stream.

What conservation efforts are currently being undertaken for the Atlantic pigtoe?

The Service and state wildlife agencies are working with numerous partners to make ecosystem management a reality, primarily by providing technical guidance and offering development of conservation tools to meet both species and habitat needs in aquatic systems from Virginia to Georgia. Land trusts are targeting parcels for acquisition, federal and state biologists are surveying and monitoring species occurrences, and recently there has been a concerted effort to ramp up captive propagation and population restoration via augmentation, expansion and reintroduction efforts.

The Service is working with Wake County, North Carolina Wildlife Resources Commission, and North Carolina State University to establish an Eastern North Carolina Freshwater Mussel Propagation Facility at the Historic Yates Mill County Park near Raleigh, N.C. The facility will be the second in the state to complement the work done in western North Carolina at the Marion Fish Hatchery in McDowell County.

The Yates Mill Pond will be a reliable source of untreated, free-flowing water with the necessary algae and nutrients for the Atlantic pigtoe and other mussels to thrive.

How would the Atlantic pigtoe benefit from an ESA listing?

Species listed as threatened or endangered under the ESA benefit from conservation measures that include recognition of threats to the species, implementation of recovery actions, and federal protection from harmful practices. Recognition under the ESA results in public awareness and conservation by federal, state, tribal and local agencies, as well as private organizations and individuals. The ESA encourages cooperation with the states and other partners to conserve listed species.

The ESA also requires the Service to develop and implement recovery plans for the conservation of threatened and endangered species. Recovery plans outline actions that are needed to improve the species’ status so it no longer requires protection under the ESA. The Service develops and implements these plans in partnership with species experts; other federal, state and local agencies; tribes; nongovernmental organizations; academia; and other stakeholders. Recovery plans also establish a framework for partners to coordinate their recovery efforts and provide estimates of the cost of implementing recovery tasks. Examples of typical recovery actions include habitat protection, habitat restoration, research, captive propagation and reintroduction, outreach and education.

Under the ESA, federal agencies must ensure actions they approve, fund or carry out do not jeopardize the continued existence of a listed species or destroy its critical habitat. In addition, under the ESA, threatened and endangered wildlife cannot be killed, hunted, collected, injured or otherwise subjected to harm. Protected fish, wildlife and plants, cannot be purchased or sold in interstate or foreign commerce without a federal permit.

What is critical habitat?

When the Service proposes an animal or plant for listing as endangered or threatened under the ESA, we identify specific areas that contain the physical or biological features essential to its conservation. This is the species’ critical habitat. The ESA requires the Service to designate critical habitat when it is both “prudent and determinable.” Determinable means that the species habitat needs can be ascertained and defined.

Critical habitat is a tool that supports the continued conservation of imperiled species by guiding cooperation within the federal government. Designations affect only federal agency actions or federally funded or permitted activities.

Is private land included in the proposed critical habitat designation?

All streams being proposed as critical habitat are navigable waters, and the streambeds are owned by the states in which they are located. Ownership of the riparian land adjacent to the proposed critical habitat is a mix of private lands and conservation parcels, including easements as well as state owned gamelands and parks.

Does proposed critical habitat for the pigtoe overlay with designated critical habitat for other listed species in this same geography?

Yes, 30 miles of the lower Tar River of the proposed critical habitat for the Atlantic pigtoe overlap with designated critical habitat for Atlantic sturgeon.

Would water management, grazing or oil and gas activities in the rivers and streams where the Atlantic pigtoe is found be affected by the proposed listing?

The designation of critical habitat on private land has no impact on private landowner activities that do not require federal funding or federal permits. If these types of projects require federal funding or permits, then the applicant would have to consult with the Service as a part of the project process. In these initially informal conversations, the Service and applicant work together to figure out how to avoid and minimize impacts to the species. If access to the stream is an issue (e.g., for grazing), the Service encourages participation in federal programs such as the Farm Bill’s Environmental Quality Incentives Program to encourage keeping cattle out of the stream and to provide off-stream water sources.

Why should people care if mussels go extinct?

Conserving and restoring freshwater mussels benefits the people who live, work and play in nearby communities. Mussels are ecosystem engineers, filter feeders that affect their environment for the better by removing nutrients and algae from the water. Also, the algae that grow on mussel shells serve as food for insects, fish, and other animals in the river.

The disappearance of key species in aquatic food webs can cause unpredictable changes that affect species both higher and lower in the food chain.

Why are freshwater mussels important?

Mussels are monitors of aquatic health; the presence of diverse and reproducing populations of mussels indicates a healthy aquatic system, which means good fishing, good water quality for waterfowl and other wildlife species, as well as assurance that our water is safe. When mussel populations are at risk, it indicates problems for other fish and wildlife species and people.

Mussels perform important ecological functions. They are natural filters, and by feeding on algae, plankton and silts, they help purify the aquatic system. Mussels also are an important food source for many species of wildlife including otters, raccoons, muskrats, herons, egrets and some fish.

Mussels depend on the same waterways that people value, whether as a water source, favorite fishing spot, recreation area, or for their scenic qualities. Maintaining a healthy environment for mussels helps ensure these areas are available to people as well.

What can I do to help conserve the Atlantic pigtoe?

People can do a number of things to help protect freshwater species, including:

  • Conserving water to allow more water to remain in streams.
  • Using pesticides and herbicides responsibly, avoiding areas around streams and lakes to prevent runoff into mussel habitats. Most street drainage flows to nearby streams.
  • Controlling soil erosion by planting trees and plants to avoid runoff of sediments into freshwater areas.
  • If you live near a stream, be careful not to disturb the stream bottom; you may be damaging freshwater mussel habitat.
  • Don’t pick up any mussels that you may see in a stream. It may be one of the last few members of its species on the planet.
  • Help your family find ways to reduce the number of chemicals that you pour down the drain in your home or use on your lawn or garden.
  • Check to see if the water draining off your roof or driveway flushes directly into a stream. Plant a garden to catch the water before it enters the stream. The garden will act as a filter and help purify the water.
  • Recycle as much as you can to reduce the amount of waste you place in the garbage.
  • Support conservation efforts that protect these unique animals and the habitats they live in.
  • Become a biologist and discover new ways to help protect freshwater mussels and other wildlife.
  • Learn more about how the destruction of habitat leads to loss of endangered and threatened species and our nation’s plant and animal diversity. - Discuss with others what you have learned.
  • Support local and state initiatives for watershed and water quality protection and improvement.

How can the public submit information on the proposal?

Written comments and information concerning the proposed listing rule will be accepted until December 10, 2018, and may be submitted by one of the following methods:


Go to the Federal eRulemaking Portal:

In the Search box, enter FWS–R4–ES–2018–0046, 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 “Comment Now!”

By hard copy

Submit by U.S. mail or hand-delivery to Public Comments Processing, Attn: FWS–R4–ES–2018–0046; U.S. Fish & Wildlife Headquarters, MS: BPHC, 5275 Leesburg Pike, Falls Church, VA 22041-3803.

The Service will post all comments on This generally means the agency will post any personal information provided through the process. The Service is not able to accept e-mails or faxes.

Who can I contact if I need more information?

For additional information, contact Pete Benjamin, U.S. Fish, and Wildlife Service, Raleigh Ecological Services Field Office, 551 Pylon Drive, Raleigh, North Carolina 27636-3726, by telephone 919-856-4520 extension 11. Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay Service (FIRS) at 800–877–8339.

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