We are proposing to remove Chipola slabshell (Elliptio chipolaensis) and fat threeridge (Amblema neislerii), both freshwater mussels, from the Federal List of Endangered and Threatened Wildlife.

According to the best available science and commercial information, threats to the Chipola slabshell and fat threeridge mussels have been removed or lessened so that the species are no longer considered threatened or endangered under the Endangered Species Act (ESA). Stream restoration and bank stabilization projects, as well as the establishment of Outstanding Florida Waters (OFWs), helped move the needle for these species. They are now found in more places in the Apalachicola-Chattahoochee-Flint (ACF) River Basin than before, there are more of them, and they are expected to remain viable into the foreseeable future. 

Declines in water quality, loss of stream flow, and fragmented riparian riparian
Definition of riparian habitat or riparian areas.

Learn more about riparian and stream habitats led to listing the Chipola slabshell as threatened and the fat threeridge as endangered in 1998. Scientists expected climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

Learn more about climate change and urbanization to increase these threats.

The Chipola slabshell and fat threeridge are both part of the Unionidae family, which is a large group of freshwater mussels with 298 species in North America. These two mussels are unique to the ACF River Basin, which spans approximately 385 miles and covers parts of Georgia, Florida, and Alabama.

The Chipola slabshell is found in the Chipola River system, a main tributary to the Apalachicola River, in Alabama and Florida. The fat threeridge inhabits the Apalachicola (Florida), Flint (Georgia), and Chipola (Florida) River systems.

Chipola slabshell
(1) The one existing population must exhibit a stable or increasing trend, natural recruitment, and multiple age classes; (2) the population from Criterion 1 occupies each of the three delineated units to protect against extinction from catastrophic events and maintain adaptive potential; and (3) threats are addressed and/or managed to the extent that the species will remain viable into the foreseeable future. All three criteria have been met or exceeded. 

Fat threeridge
(1) At least four populations exhibit a stable or increasing trend, evidenced by natural recruitment and multiple age classes; (2) at least one population from Criterion 1 occupies each of the Flint and Chipola sub-basins, and one population occupies two of the three delineated units in the Apalachicola sub-basin for fat threeridge; (3) threats have been addressed or managed to the extent that each species will remain viable into the foreseeable future. All three criteria have been met. 

Conservation partners include the U.S. Army Corps of Engineers, Florida Fish and Wildlife Conservation Commission, U.S. Department of Agriculture, Apalachicola Riverkeeper, and many more like-minded groups.

The Florida Ecological Services Office is preparing a post-delisting monitoring plan to ensure the mussels remain healthy and secure from the risk of extinction. The plan summarizes the species’ status at the time of delisting, defines thresholds or triggers for potential monitoring outcomes and conclusions, and lays out the frequency and duration of monitoring. It also articulates monitoring methods including sampling considerations, outlines compilation and reporting procedures and responsibilities, and proposes a post-delisting monitoring implementation schedule, including timing and responsible parties.

Additionally, both species also co-occur with other threatened and endangered species found in the ACF River Basin, such as purple bankclimber, shinyrayed pocketbook, gulf moccasinshell, Ochlockonee moccasinshell, oval pigtoe, and the proposed endangered Southern elktoe. Since Chipola slabshell and fat threeridge occur in the same drainages as these species, they will be afforded some continued level of indirect protection once delisted. 

The Service seeks comments on this proposed rule until Monday, December 30, 2024. Using the Federal eRulemaking Portal, search for docket number FWS-R4-ES-2024-0051. Comments submitted electronically must be received by 11:59 p.m. Eastern Time on the closing date. The agency must receive requests for public hearings in writing at the address shown below by December 13, 2024.  

 For more information contact:  Gianfranco Basili, Deputy State Supervisor, Florida Ecological Services Field Office, (904) 228-2503, 7915 Baymeadows Way, Suite 200, Jacksonville, FL 32256-7517.  Persons who use a telecommunications device for the deaf (TDD) may call the Federal Relay Service at 800–877–8339.