Characterizing the larval fishes of the Ogeechee River

REU Fellow: Jewel Streeter, Ogeechee Technical College

Mentor: Dr. Jamie Roberts

The habitat ecology of larval stream fishes is poorly known relative to adults, yet larval habitats might be particularly vulnerable to anthropogenic influences. We characterized abundance of larval fishes in river-margin versus the main-channel habitats of the Ogeechee River, a Coastal Plain stream with a diverse fish community. Our primary goals were to discern which groups of fishes use which types of larval habitats and how this use changes over time. The study extended from 6/19 through 7/11, with collections made weekly via light traps and drift nets to sample river-margins and main-channel habitats, respectively. 338 individuals were identified to seven families. Among the families, Cyrpinidae and Centrarchidae comprised 86% of individuals. The proportional distribution of families differed significantly between the two methods (P<0.0001) and among sampling dates (P<0.003). Two families, Atherinidae and Ictaluridae, showed variance between methods and over time. The 6/19 sampling set was during a high flow event, accompanied by a greater amount of larval fish caught in the main-channel versus the margins. Additionally, among Cyprinidae there was a trend of multiple size modes over time. This preliminary study indicates that fish families utilize larval habitats differentially and that larval fish sampling may be a way to observe reproductive success and timing.