Life history and habitat use of the juvenile Alabama shad ( Alosa alabamae) in northern gulf of Mexico rivers
The Alabama shad, Alosa alabamae, is an anadromous species that is in decline and has seen extirpations from impoundments as well as decreased water quality. Alabama shad live in the Gulf of Mexico and ascend Northern Gulf of Mexico Drainages to reproduce early in the year (January-May). The juveniles spend the majority of the year in these freshwater systems before emigrating out to the Gulf of Mexico as late as December. This dissertation focuses on the juvenile life stages that occur within the Northern Gulf of Mexico drainages. Spawning conditions of the river, as well as the habitat and diet, are studied and documented. Habitat use of the juvenile Alabama shad shifted from sand bars to open channel and banks which was seen in progression as the juveniles increased in size and maturity. Important physicochemical parameters that influenced the presence of Alabama shad within these habitats ranged from temperature, flow velocity, and conductivity. Diet of the juvenile Alabama shad consisted of particulate detritus within Alabama shad <50mm and a host of terrestrial and aquatic insects as the Alabama shad matured. Hatch timing was documented between the drainages sampled from early January through March. Spring flows followed a falling trend with increasing temperatures. These findings suggest that the management of these drainages should be done independently on a drainage-by-drainage basis. Habitats are consistent between>drainages, but the physicochemical factors driving the presence of this species are unique to each drainage. It is also suggested that maintaining natural flows for habitat maintenance and reproductive cues is important toward conservation of the species.