ESTUARINE FINFISH AND INVERTEBRATE SURVEY IN THE BACKBAY SYSTEM OF FIRE ISLAND AND WEST HAMPTON ISLAND, NEW YORK

This report presents the study design, methodologies and results from a one-year survey of the intertidal wetlands along the south shore of Long Island, New York. This project was designed to provide information that will assist the United States Army Corps of Engineers in evaluating project alternatives to the Fire Island to Montauk Point Reformulation Study. The primary goal is to gather data in order to develop a baseline from which impacts of the backbay habitat can be assessed, in the event of breaching for example. This survey provides information on the community structure of backbay estuarine ecosystems. Specifically, this project identifies finfish, invertebrates and botanical species found in the study area. Additionally, spatial and temporal trends in community structure are examined. Analysis of data from the first year of study indicated the following trends in community structure. A shoreline seine survey showed a strong seasonal link in finfish and invertebrate abundances in all three bays sampled, Shinnecock, Moriches and Great South Bays. Animal abundances peaked during the summer and were lowest during the winter and spring months. Finfish catches were dominated by M. menidia. Other species of importance were A. americanus, F. majalis, A. mitchilli and F. luciae. Landings of crabs and shrimps were dominated by C. sapidus, C. septemspinosa and P. vulgaris. Species diversity fluctuated throughout the year. Spatial analyses indicate that Great South Bay had lower abundances of finfishes than Moriches and Shinnecock Bays. There is also some indication that stations near inlets had higher catches. Conversely, invertebrate abundances appeared to be lower at stations near inlets and peaked at more protected locations. Fluctutations in environmental variables such as temperature, salinity, dissolved oxygen and turbidity do not appear to have a significant effect on animal abundances in the bays. However, it is important to note that temperature is a trigger for spawning activity of most species in the bay. Peak abundances occur during the summer, when temperatures are warmest. Salinity is also considered to be an important factor in determining benthic animal distributions. A survey of the marshes identified S. alterniflora as the primary vegetation. There is a high variation in S. alterniflora biomass at different locations, indicating a patchy distribution. Fundulus spp. Were the most abundant finfishes in the marshes. Collections of animals were low in the marsh areas. In Great South Bay the abundance of finfishes appears to increase with increasing vegetation, while in Moriches and Shinnecock Bays the alternate is true. Invertebrate abundances appear to increase with increasing vegetation in all three bays.