Habitat use by telemetered Alabama Shad during the spawning migration in the lower flint river, Georgia

Abstract

The Alabama Shad Alosa alabamae is an anadromous clupeid that lives in the northern Gulf of Mexico and ascends freshwater rivers in spring to spawn. Populations have experienced substantial range-wide declines due to habitat alteration. The largest known population of Alabama Shad is found in the Apalachicola River in northwest Florida. To assess their movement during the spawning migration, 250 Alabama Shad were fitted with acoustic or radio transmitters, depending on year, and transported upstream from Jim Woodruff Lock and Dam during 2010–2014. The 153 relocations from 126 individual fish revealed congregation areas that were suspected to be spawning locations. Alabama Shad selected limerock boulder substrate, avoided limerock fine and rocky substrates and used sandy substrate in the same proportion as its availability. Alabama Shad upstream movement was greatest during April through mid-May. Movements ≥ 20 km were generally clustered together over a period of a few days, with ~90% of such movements occurring following periods of increased river discharge. All limerock boulder substrate areas on the lower Flint River were identified to focus future efforts to determine exact spawning locations.