SLOAN, N. J.B.*; GOODFRIEND, E.; JOHNSON, K.B.; Florida Institute of Technology: Zooplankton Abundance and Distribution in Tidal Marshes Impounded for Mosquito Control

Seventy-five percent of tidal marsh areas along the Indian River Lagoon (IRL) are impounded for mosquito control. Canals within these areas are habitat used as nurseries by juvenile fish, which in many cases feed on impoundment zooplankton. Our study examined the diversity, abundance, and distribution of zooplankton at six impoundments in the IRL representing a range of distances from a coastal inlet. We identified and counted zooplankton, then compared them between sites and also compared within sites between the culvert (impoundment entrance) and the �heart� (deeper into the impoundment). For overall impoundment numerical abundance of zooplankton (pooled), flatworms composed 44%, copepods 25%, nauplii 18%, rotifers 7%, veligers 3%, and all other organisms 3%. Zooplankton diversity varied between the heart and the culvert and we believe this is due to flow rates, with lower flows allowing higher diversity. Zooplankton also varied between sites, possibly due to the proximity of the coastal inlet. In both cases, patterns may be the result of hydrographic supply of zooplankton and the influence of water exchange through the coastal inlet (between site differences) or through the culvert (within site differences).