Background
The Apalachicola River provides habitat for an endemic freshwater mussel (Family: Unionidae) the fat threeridge, Amblema neislerii, which was listed as endangered on 15 April 1998 (Federal Register 63(50): 12664-12687).

Issues

• Misleading Recovery Plan (Butler et al. 1999)
• Lack of a clear understanding by resource managers and others that this species is doing extremely well in appropriate habitat in the Apalachicola River. It is however, endemic, and could be negatively affected by developments in the river.
• The species probably should never have been listed as endangered; now it should be down-listed to threatened.

Approach
Currently the Mobile District conducts surveys at habitats suitable for this species that are likely to be affected by dredging or related projects. If the species is found, it is usually relocated to other sites. A new approach would be to conduct a detailed analysis of this species habitat requirements and distribution, rewrite the Recovery Plan, and then reassess its status.

Benefits
A re-evaluation of the status of this species would allow the Mobile District and resource agencies direct their attention to organisms and issues of the greatest concern.

Status
This species has also been collected in tributaries to the Apalachicola River; however, it evidently has always been uncommon at most of these other locations. This species is very similar to the widespread threeridge mussel, Amblema plicata. At moderately depositional sites along the Apalachicola River this species is abundant, can dominant the molluscan fauna, and exhibits good evidence of recent recruitment.

Partners
U.S. Army Engineer District, Mobile; ERDC; USFWS Field Office in Panama City, Florida

References
Butler, R. S., and S. K. Alam. 1999. Technical/Agency Draft Recovery Plan for Endangered fat threeridge (Amblema neislerii), shinyrayed pocketbook (Lampsilis subangulata), Gulf moccasinshell (Medionidus penicillatus), Ochlockonee Moccasinshell (Medionidus simpsonianus), oval pigtoe, and threatened Chipola slabshell (Elliptio chipolaensis), and purple bankclimber (Elliptoideus sloatianus). Prepared for the Southeast Region of the U.S. Fish and Wildlife Service, Atlanta, Georgia.

POC
Andrew C. Miller and Barry S. Payne