Listing Status
- Federal Status: Threatened
- FL Status: Federally-designated Threatened
- FNAI Ranks: G1/S1 (Critically Imperiled)
- IUCN Status: EN (Endangered)
Description
The Chipola slabshell is a midsized freshwater mussel that can reach a length of 3.3 inches (8.5 centimeters). This species is oval shaped with a reddish-brown outer shell, sometimes surrounded with dark and light bands, and a reddish-yellow inner shell (University of Georgia 2008).
History
The Chipola slabshell is a filter feeder (filters food out of water) and their diet primarily consists of plankton and detritus (dead organic matter).
Due to its rarity, little is known about the life history of the Chipola slabshell. It is believed that males release sperm in the water and the female receives the sperm through its siphon. Eggs are fertilized in the female’s shell and the glochidia (larvae) release into the water. The larvae attach to the gills or fins of a host fish to develop. When the larvae metamorphose into juvenile mussels, they release from the fish and settle in their primary habitat.
Habitat
The Chipola slabshell inhabits slow to medium current rivers with a sand and silt floor (Bogan 2000). This species is found only in the Chipola River in northwest Florida.
Threats
Freshwater mussels face a host of threats due to an increased human population, pollution, and development. The main threat is the impoundment of fresh waterways. Waterways are impounded for reasons including for fresh water supply, flood control, and hydropower. Impounding causes the water current’s velocity to decrease causing sediment to build up in the river and covering the mussels located in the substrate. Impoundments also cause habitat fragmentation, separating mussel populations and also individual mussels from algae and host fish (U.S. Fish & Wildlife Service 2006). River dredging also threatens to destroy freshwater mussel populations on the river floors. The Asian clam (Corbicula fluminea), an invasive species, can out-compete the Chipola slabshell for resources in its habitat (Florida Natural Areas Inventory 2001). Pesticide and chemical pollution also pose a significant threat to mussels, since they are filter feeders and may ingest chemicals directly from their habitat.
Conservation
The Chipola slabshell is protected as a Threatened species by the Federal Endangered Species Act and as a Federally-designated Threatened species by Florida’s Endangered and Threatened Species Rule. It is one of the target species in a 7-species Federal Recovery Plan. Specific actions needed to recover the species include (USFWS 2003):
- Secure extant subpopulations and currently occupied habitats and ensure subpopulation viability.
- Search for additional subpopulations of the species and suitable habitat.
- Determine through research and propagation technology the feasibility of augmenting extant subpopulations and reintroducing or reestablishing the species into historical habitat.
- Develop and implement a program to evaluate efforts and monitor subpopulation levels and habitat conditions of existing subpopulations, as well as newly discovered, reintroduced, or expanding subpopulations.
- Develop and utilize a public outreach and environmental education program.
- Assess the overall success of the recovery program and recommend actions.
References
Bogan, A.E. 2000. Elliptio chipolaensis. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1. <iucnredlist.org>. Downloaded on 11 July 2011.
Florida Natural Areas Inventory. 2001. Field guide to the rare animals of Florida. https://www.fnai.org/FieldGuide/pdf/Elliptio_chipolaensis.pdf
University of Georgia. (2008). Chipola slabshell Elliptio chipolaensis. Retrieved July 11, 2011, from Georgia Museum of Natural History: http://naturalhistory.uga.edu/
U.S. Fish and Wildlife Service. 2003. Recovery Plan for Endangered Fat Three ridge (Amblem neislerii), Shinyrayed Pocketbook (Lampsilis subangulata), Gulf Moccasinshell (Medionidus penicillatus), Ochlockonee Moccasinshell (Medionidus simpsonianus), and Oval Pigtoe (Pleurobema pyriforme): and Threatened Chipola Slabshell (Elliptio chipolaensis), and Purple Bankclimber (Elliptoideus sloatianus). Atlanta, Georgia. 142 pp.
U.S. Fish & Wildlife Service. (2006, June 8). Current Threats. Retrieved July 7, 2011, from Freshwater Mussels : http://www.fws.gov/midwest/mussel/current_threats.html