Rediscovery and genetic confirmation of the Threeridge Mussel, Amblema plicata (Say, 1817) (Bivalvia, Unionidae), in the Choctawhatchee River, Florida, USA

Recent freshwater mussel research has resulted in rediscovery of several species presumed extinct. We report the rediscovery of Amblema plicata (Say, 1817) in 2019 from the Choctawhatchee River, Florida, USA. Amblema plicata has not been reported in the Choctawhatchee river basin since 1958, more than 61 years ago. This species was collected during the long-term monitoring of freshwater mussels in Florida streams. We provide genetic confirmation of our voucher identification using a DNA barcoding approach and discuss potential risks to A. plicata populations in the Choctawhatchee river basin.

Evaluating Water Balance Variables under Land Use and Climate Projections in the Upper Choctawhatchee River Watershed, in Southeast US

Changes in water balance variables are essential in planning and management. Two major factors affecting these variables are climate change and land use change. Few researches have been done to investigate the combined effect of the land use change and climate change using projections. In this study the hydrological processes in Upper Choctawhatchee River Watershed were modeled using the Soil and Water Assessment Tool (SWAT) to investigate the impacts of climate and land use change. We integrated land use projection based in the Shared Socioeconomic Pathways with future climate data to study the combined effects on Hydrological response of the watershed. Future rainfall and temperature, for two time periods, were obtained using General Climate Models to provide SWAT with the climatic forcing in order to project water balance variables. The simulation was carried out under two radiative forcing pathways of RCP4.5 and RCP6.0. Land use change focused on urbanization dominated the climate changes. Impacts on water balance variables differed seasonally. Results showed surface runoff experienced major changes under both emissions scenarios in some months up to 5 times increase. Among the water balance variables, evapotranspiration (ET) as the least dominant pathway for water loss showed the modest changes with the largest decrease during fall and summer. Projection indicated more frequent extreme behavior regarding water balance during midcentury. Discharge was estimated to increase through the year and the highest changes were projected during summer and fall with 186.3% increase in November under RCP6.0. Relying on rainfall for farming along with reduced agricultural landuse (11.8%) and increased urban area (47%) and population growth would likely make the water use efficiency critical. The model demonstrated satisfactory performance, capturing the hydrologic parameters. It thus can be used for further modelling of water quality to determine the sustainable conservation practices and extreme weather events such as hurricane and tropical storms.

Managing Centrarchid Fisheries in Rivers and Streams

<em>Abstract.</em>—The Choctaw Bass <em> Micropterus cf. punctulatus </em>is an undescribed black bass found in coastal river systems of northwest Florida and southern Alabama. The Choctaw Bass is morphologically similar to the Spotted Bass <em> M. punctulatus</em>. Prior to this study, there was no published life history information specific to this black bass. The need to address these information gaps was further influenced by the popularity of black bass fishing and potential statewide black bass regulation changes in Florida. Our research examined relative abundance, age, mortality, growth, and diet of Choctaw Bass collected from the Choctawhatchee River, Florida and Holmes Creek, a major tributary of the Choctawhatchee River in fall 2012 and 2013. Choctaw Bass were compared to sympatric Largemouth Bass <em> M. salmoides </em>× Florida Bass <em> M. floridanus </em>intergrades. Relative abundance was lower for Choctaw Bass than Largemouth Bass in both the Choctawhatchee River and Holmes Creek. The oldest Choctaw Bass from the Choctawhatchee River was age-5 and the oldest Choctaw Bass from Holmes Creek was age-11. Total instantaneous mortality of Choctaw Bass was statistically similar between the study areas. Total instantaneous mortality for Choctaw Bass from Holmes Creek was also similar to sympatric Largemouth Bass. Growth differed for Choctawhatchee River and Holmes Creek Choctaw Bass. Diets of Choctaw Bass collected from the Choctawhatchee River consisted primarily of fish while diets of Choctaw Bass and Largemouth Bass collected from Holmes Creek consisted primarily of crayfish. The observed restricted distribution, limited abundance relative to Largemouth Bass, limited number of Choctaw Bass collected greater than 406 mm TL, and the lack of Choctaw Bass older than age-5 in the Choctawhatchee River led to the recommendation that Choctaw Bass be managed separately from Largemouth Bass.

Anadromous Sturgeons: Habitats, Threats, and Management

Abstract.—Migrations and movements of Gulf sturgeon <em>Acipenser oxyrinchus desotoi </em>were determined using satellite pop-up archival transmitting (PAT) tags and acoustic telemetry. Adult Gulf sturgeon from four rivers in northwestern Florida were caught with gill nets and were tagged with PAT and acoustic tags in the fall of 2001 and 2002. PAT tags were programmed to release in early February 2002 and 2003 to provide information about location of late-winter marine habitats. However, only 5 of 25 provided meaningful location information. Three of the PAT-tagged fish were relocated acoustically near the PAT tag pop-up locations, one of which was in Choctawhatchee Bay. Acoustic searches near Gulf of Mexico pop-up locations led to acoustic relocation of one nonreporting PAT-tagged fish and five fish tagged with acoustic transmitters only. Many of these fish were relocated on several dates in late winter, and many (including fish from the Yellow, Choctawhatchee, and Apalachicola rivers) were concentrated in a 25-km stretch of the Florida Panhandle coast, within 2 km from shore, and in depths less than 6 m. A fish that had been tagged with a PAT tag in the Yellow River was acoustically relocated in the concentration area and then in the Choctawhatchee River the following summer. It returned to the concentration area again the next winter and returned to the Choctawhatchee for the second summer. An acoustic-tagged fish was relocated very near a PAT tag pop-up location about 30 km south of the Suwannee River, within 12 km from shore, and in depths of 3–4 m. Pop-up locations and acoustic relocations showed that the Gulf sturgeon had migrated distances of at least 30– 180 km. These findings indicate a pattern in which Gulf sturgeon migrate considerable distances along the coastline, sometimes to specific areas of concentration, sometimes mixing with other populations, and primarily utilizing shallow (2–6 m), nearshore areas as late-winter habitats. This pattern is similar to that reported by others in this volume for Atlantic sturgeon <em>Acipenser oxyrinchus</em> and for green sturgeon <em>A. medirostris</em>.