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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.

Reopening of comment period on revised proposal to list Atlantic pigtoe as threatened under the ESA

What action is the U.S. Fish and Wildlife Service taking on the Atlantic pigtoe?

The Service is reopening the comment period on the below proposed actions:

  1. Proposed listing of the Atlantic pigtoe, a freshwater mussel native to rivers of the Atlantic seaboard, as threatened under the Endangered Species Act (ESA).
  2. Designate 566 river miles of critical habitat across 18 units.
  3. Implement a special rule under section 4(d) of the ESA that would streamline and exempt from the regulatory process certain management actions that benefit the mussel.

What are the differences between the original proposal and the revised proposal?

The Service now proposes designating a total of 566 miles as critical habitat for the Atlantic pigtoe across 18 units within portions of 11 counties in Virginia and 17 counties in North Carolina. We added length to three critical habitat units and added two new units. This is a total increase of 24 miles in the stream mileage we proposed to designate in our October 11, 2018 proposed rule.

We also propose changes to a special rule under the ESA’s section 4(d). The revised section 4(d) language allows for surveys and relocation of Atlantic pigtoe prior to stream restoration along river banks, and clarifies best management practices for forestry/agricultural practices.

Why were changes needed to the original proposal?

During a comment period held from October 10 through November 11, 2018, we received new information, including new data collected since the first version of the species status assessment report, which was finalized in December 2016. We also determined we had accidentally omitted in the proposed rule a recorded observation from 2011 in the Nottoway River Basin, Dinwiddie County, VA.

Do I need to resubmit comments or questions that I provided during the first comment period?

No. If you submitted comments or information on the October 11, 2018, proposed listing rule, proposed designated critical habitat and associated economic analysis, and proposed special rule under section 4(d) of the ESA during the initial comment period (October 11, 2018 to December 10, 2018), please do not resubmit them. Any such comments are already part of the public record of this rulemaking proceeding, and we will fully consider them in the preparation of our final determination. Our final determination will take into consideration all written comments and any additional information we receive during both comment periods.

What is the Atlantic pigtoe?

The Atlantic pigtoe is a freshwater mussel 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.

Why is the Atlantic pigtoe proposed to be listed as threatened under the ESA?

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 collaborate to conserve and bring back this mussel. Experts compared occurrences across the landscape over time and found that the Atlantic pigtoe has been lost from 60 percent of its historical range.

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, 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 ESA protection?

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.

Critical habitat designation does not affect land ownership or establish a wildlife refuge, reserve, preserve, or other conservation areas. The designation of critical habitat on private land has no impact on individual landowner activities unless they require federal funding or federal permits.

The regulatory implications of designating critical habitat apply to actions that involve a federal permit, license, or funding. If this is the case, the Service works with the federal agency and, where appropriate, private or other landowners to amend their project to allow it to proceed without adversely modifying the critical habitat. Most federal projects are likely to go forward and could be modified to minimize harm to critical habitat.

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 game lands and parks.

Does proposed critical habitat for the Atlantic 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 individual landowner activities unless they 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 initial 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. In addition, 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 are also 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.

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