Analyzing Spatial and Temporal Trends in Community Structure of the Peconic Bay Estuary

Understanding the temporal and spatial trends in community structure of a bay is critical to elucidating drivers of ecosystem change and developing management policies.  In order to analyze the spatial and temporal trends in the fish and mobile invertebrate assemblage of Peconic Bay, New York, we utilized data from the NYDEC bottom trawl survey.  Beginning in 1987, the survey has been conducted monthly from May through October and averaged 381 stations annually.  Abundance data for forty-two species were analyzed using multi-scale ordination on Hellinger transformed abundance data. Temporal trends in community structure revealed strong seasonal patterns typical of a temperate estuarine system. However, a long-term pattern was observed where assemblage became gradually more dissimilar as the time interval between surveys was increased.  Preliminary results suggest that during the study period the community structure continually changed without abrupt transitions associated with regime shifts. Spatial analysis utilizing mapping of benthic grain size and ordination results are explored to determine which species were associated with specific habitat types.