The U.S. Fish and Wildlife Service is proposing to list two species of freshwater mussels – the Salina mucket and Mexican fawnsfoot - as endangered under the Endangered Species Act (ESA) and proposing to designate critical habitat for each. The mussels historically ranged throughout the mainstem Rio Grande and select major tributaries in Texas and Mexico, but today have been reduced to single populations that occupy only a fraction of this area.
“In making this proposed listing determination, the Service carefully assessed the status of the Rio Grande mussels, including the past, present and future threats that they face,” said Amy Lueders, the Service’s Southwest Regional Director. “Because the single existing populations of both species have low abundance, limited recruitment, and no ability to disperse into new areas, they are extremely vulnerable to extinction.”
After examining the best available scientific information available for the two freshwater mussels, the Service determined that both mussel species meet the definition of endangered under the ESA. The primary factors that influence the species’ viability include accretion of fine sediments, the loss of flowing water, and impairment of water quality.
The Salina mucket historically occurred in the Texas portion of the Rio Grande drainage in the United States and Mexico, but today can only be found in the Lower Canyons and Martin Canyon portions of the Rio Grande just downstream of Big Bend National Park. The Service is proposing to designate approximately 199.5 river miles of critical habitat for this species in Brewster, Terrell, and Val Verde counties, Texas.
The Mexican fawnsfoot historically occurred in the Rio Grande from the confluence of the Pecos River downstream to just below the current location of Falcon Dam, but today can only be found from Eagle Pass, Texas downstream to San Ygnacio, Texas. The Service is proposing to designate approximately 185.7 river miles of critical habitat for this species in Maverick, Webb, and Zapata counties, Texas.
Critical habitat identifies geographic areas that contain the physical or biological features essential to the species’ conservation. The designation requires federal agencies to consult with the Service on any actions that may affect critical habitat. It does not affect land ownership and imposes no requirements on state or private actions on state or private lands where no federal funding, permits, or approvals are required.
Plants and animals such as mussels are a critical part of healthy, functioning ecosystems. Sensitive to pollution, native mussels are indicators of broader stream health – vibrant mussel populations typically reflect a healthy stream. In addition to being indicators of stream health, mussels clean water as they feed, filtering their food from the water column, and with it, sediment, algae and other constituents, which benefits people and wildlife.
Of the approximately 300 species of freshwater mussels occurring in North America, over 70% are considered endangered, threatened, or of special concern due to the loss, fragmentation and degradation of freshwater streams and rivers.
The ESA is extraordinarily effective at preventing species from going extinct and has inspired action to conserve at-risk species and their habitat before they need to be listed as threatened or endangered. Since it was signed into law in 1973, more than 99 percent of all species listed under the law are still with us today.
We encourage the public, academia, federal and state agencies, tribes, industry and other stakeholders to review the proposal and provide comments during a 60-day public comment period, which begins when the rule and supporting documents are published in the Federal Register.
The proposed listing and critical habitat will publish in the Federal Register on July 25, 2023 and public comments will be accepted until September 25, 2023.
A final decision to list or withdraw the proposal is typically made within a year after the proposal is published in the Federal Register.
Q: What actions are being taken by the U.S. Fish and Wildlife Service?
A: The U.S. Fish and Wildlife Service (Service) is proposing to list the Salina mucket and Mexican fawnsfoot as endangered under the Endangered Species Act (ESA). The Service is proposing to designate approximately 199.5 river miles of critical habitat for the Salina mucket in Brewster, Terrell, and Val Verde counties, Texas, along with 185.7 river miles of critical habitat for the Mexican fawnsfoot in Maverick, Webb, and Zapata counties, Texas.
Publishing the proposed listing and critical habitat begins a 60-day public comment period on the proposed rule and supporting documents. The proposed listing and critical habitat will publish in the Federal Register on July 25, 2023 and public comments will be accepted until September 25, 2023.
We encourage the public, academia, federal and state agencies, industry and other stakeholders to review the proposal and provide comments. Our decision to list the mussel species or withdraw our proposal will be based on the best available science. A final decision to list or withdraw the proposal is typically made within a year after the proposal is published in theFederal Register.
Q: What is the science behind these decisions?
A. The proposal to list these species under the ESA is based on the best scientific and commercial data available and recently completed Species Status Assessment (SSA). Biologists from the Service developed the report with input from species experts and other partners. Our SSA analyzed individual, population, and species requirements, as well as factors affecting the species’ survival and their current conditions, to assess the species’ current and future viability in terms of resilience, redundancy, and representation.
After careful examination of the best available scientific information available for the two freshwater mussels, including estimates of current and future conditions, the Service determined that Salina mucket and Mexican fawnsfoot are in danger of extinction throughout all of their range and meet the definition of endangered under the Endangered Species Act.
Q: What is the difference between threatened and endangered species under the ESA?
A: “Endangered” is defined by the ESA as a species that is currently in danger of becoming extinct throughout all or a significant portion of its range. “Threatened” is defined as a species that is likely to become endangered in the foreseeable future.
Q: Where are the mussel species found, and what are the threats to the species?
A: The Salina mucket historically occurred in the Texas portion of the Rio Grande drainage in the United States and Mexico. The only known remaining population of Salina mucket is located in the Lower Canyons and Martin Canyon portions of the Rio Grande just downstream of Big Bend National Park in Brewster, Terrell, and Val Verde counties, Texas.
The Mexican fawnsfoot historically occurred in the Rio Grande from approximately the confluence of the Pecos River with the Rio Grande in Val Verde County to downstream just below the current location of Falcon Dam. The only remaining Mexican fawnsfoot population occurs from approximately Eagle Pass, Texas downstream to San Ygnacio, Texas in Zapata County.
Both species currently occur in single extant populations that have undergone significant range reductions. The primary reasons for these range reductions are reservoir construction and unsuitable water quality.
The primary physical and biological features that influence the resiliency of the Salina mucket and Mexican fawnsoot include water quantity, availability of instream habitats, availability of and access to host fish, and adequate water quality.
Neither species are found in lakes, ponds, reservoirs, or pools without flow, or in areas that are regularly dewatered.
Q: What is critical habitat?
A: Critical habitat identifies geographic areas occupied at the time a species is listed that contain at least one of the physical or biological features essential to the species’ conservation. Critical habitat may also include areas outside the geographic area the species occupied when listed that are essential for conserving the species. The ESA defines “conservation” as the actions leading to a species’ eventual recovery so that it no longer requires ESA protections.
Critical habitat provides protection against “destruction or adverse modification” of habitat essential to the species from actions carried out, funded, or authorized by a federal agency, as required by the ESA under section 7. Under such consultations, the Service reviews federal actions for how they affect the “physical or biological features essential to conserve a listed species” and that habitat’s ability to support the species throughout its lifecycle and to meet the species’ recovery needs.
Designating critical habitat does not affect land ownership or establish a refuge, wilderness, reserve, preserve, or other . A critical habitat designation identifies areas that are important to conserve federally listed threatened or endangered species. A critical habitat designation requires federal agencies to consult with the Service on any of their actions that may affect designated critical habitat. The Service can then recommend ways to minimize any adverse effects. It imposes no requirements on state or private actions on state or private lands where no federal funding, permits, or approvals are required.
Q: What is the purpose of designating critical habitat?
A: Critical habitat designation is a tool used to identify areas that are important to the recovery of a species. It also notifies federal agencies of areas that must be given special consideration when they are planning, implementing, or funding activities. Federal agencies are required to consult with the Service on their actions that may affect critical habitat. A critical habitat designation has no effect when a federal agency is not involved. For example, a private landowner undertaking a project that involves no federal funding or permit has no additional responsibilities if his or her property falls within critical habitat boundaries.
Q: How did the Service determine which areas to propose as critical habitat for the mussels?
A: We reviewed the available information pertaining to the biological needs of the species and habitat characteristics where these species are located.All areas proposed as critical habitat for the mussels contain one or more of the physical or biological features essential for the conservation of the species. When determining critical habitat, biologists consider habitat features necessary for all life stages and successful reproduction of the species. Habitat areas essential for mussel conservation are those that provide the biological needs of reproducing, feeding, sheltering, dispersal, and genetic exchange.
The features essential to the conservation of the Rio Grande mussels may require special management considerations or protections to reduce the following threats: increased erosion and movement of fine sediments; degradation of water quality; altered hydrology from inundation, flow supplementation causing increased scouring and stream bank collapse, or flow loss; predation and collection; and barriers to fish movement.
Q: What areas is the Service proposing to designate as critical habitat for the mussel species?
A: The Service is proposing to designate approximately 199.5 river miles of critical habitat for the Salina mucket in Brewster, Terrell, and Val Verde counties, Texas, along with 185.7 river miles of critical habitat for the Mexican fawnsfoot in Maverick, Webb, and Zapata counties, Texas.
Q: Did the ESA require an economic analysis be prepared for the proposed critical habitat?
A: Yes. A draft economic analysis was prepared for the proposed critical habitat that estimates the incremental costs associated with the proposed designation. The draft economic analysis and other information about the mussels are available at www.regulations.gov or by contacting the Austin Ecological Services Field Office at email@example.com.
Q: Do listed species with designated critical habitat receive more protection than listed species without it?
A: A critical habitat designation does not set up a preserve or refuge. It only affects activities with federal involvement, such as federal funding or a federal permit. Listed species and their habitats are protected by the ESA whether or not they are in areas designated as critical habitat.
Designation of critical habitat can help focus conservation activities for a listed species by identifying areas that contain the physical and biological features that are essential for the conservation of that species. Critical habitat also alerts the public as well as land management agencies to the importance of these areas.
Q: Do federal agencies have to consult with the Service outside critical habitat areas?
A: Yes,even when there is not a critical habitat designation, federal agencies must consult with the Service if an action they fund, authorize, or permit may affect listed species or critical habitat.
Q: What conservation efforts are currently being undertaken for the mussels?
A: The level of interest among stakeholders, regulatory agencies, and partners to better understand the status, threats, and conservation of freshwater mussels in Texas has increased significantly since 2017 when the Service initiated reviews of several species for potential listing under the Act. This led to improved communication among interested parties and multiple partnerships seeking to conduct research and improve our understanding of the health and distribution of mussel populations across Texas, as well as increased efforts to protect and conserve known populations.
In Texas, the National Park Service manage lands and waterways under their purview in the Rio Grande Watershed for native communities, including the Salina mucket. The large amount of land in conservation management in Big Bend National Park and the Rio Grande National Scenic River reduces risks to the Salina mucket from sediment inputs, habitat alterations, and contaminants.
In other Texas reaches of the Rio Grande, we are not aware of any management actions for Salina mucket or Mexican fawnsfoot.
Q: How would the mussel species benefit from an ESA listing?
A: Species listed as endangered or threatened 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 such that it no longer requires protection under the ESA. The Service develops and implements these plans in partnership with the 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 (e.g., restoration of stream flow), research, captive propagation, and reintroduction.
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, endangered animal species cannot be killed, hunted, collected, injured, or otherwise subjected to harm. Endangered species cannot be purchased or sold in interstate or foreign commerce without a federal permit.
Q: Would water management, grazing, or oil and gas activities in the rivers and streams where the mussels are found be affected by the proposed listing?
A: If the mussels are added to the list of threatened and endangered species following publication of a final rule in the Federal Register, then the Section 9 prohibitions would apply. Thus, any activities resulting in take of listed mussels, directly or indirectly, would require a permit under Section 10 of the ESA. Federal agencies are required to consult on the effects of their actions to threatened and endangered species under of the ESA. Regulatory assurances, including coverage for take that is incidental to otherwise lawful activities, can be provided through Section 10 permits (Habitat Conservation Plans, Safe Harbor Agreements, and Candidate Conservation Agreements) and through Section 7 Biological Opinions.
Q. Why are freshwater mussels important?
A. Mussels are biological indicators of healthy streams and rivers that benefit people and wildlife. The presence of diverse and reproducing mussel populations indicates healthy ecosystems, good fishing, and good water quality for waterfowl and other wildlife species. It also supports safe drinking water.
Mussels perform important ecological functions. They are natural filters, and by feeding on algae, plankton, and suspended detritus 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.
Q: How can the public submit comments or information on the proposal?
A: Written comments and information concerning the proposed listing and critical habitat will be accepted until September 25, 2023 and may be submitted by one of the following methods:
- Electronically: Go to the Federal eRulemaking Portal: http://www.regulations.gov. In the Search box, enter FWS–R2-ES-2023-0026 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.
- By hard copy: Submit by U.S. mail or hand-delivery to: Public Comments Processing, Attn: FWS–R2-ES-2023-0026, U.S. Fish & Wildlife Headquarters, MS: BPHC, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
The Service will post all comments on http://www.regulations.gov. This generally means the agency will post any personal information provided through the process. The Service is not able to accept email or faxes.