Assessing the response of juvenile and adult hard clams to the new breach in Great South Bay: Post-Hurricane Sandy study

Gobler, Christopher; Stevens, Alexandra

The south shore of Long Island (NY, USA) is lined by barrier islands that have been breached by ocean waters dozens of times during the past 300 years. On October 29, 2012, Hurricane Sandy created a new breach in eastern Great South Bay (GSB) that has had a strong effect on the circulation and salinity. The effects of the breach on resident hard clam communities are, however, currently unknown. This study conducted experiments to understand how the New Inlet in GSB may be impacting the growth and condition of resident hard clam communities. Juvenile and adult hard clams were placed in cages across GSB from spring through fall of 2014. The length- and weight-based growth of the clams were quantified along with their biochemical composition. The reproductive condition of adult hard clams was also assessed seasonally. The concurrent assessment of plankton community composition and general water quality permitted a statistical assessment of the extent to which these parameters influenced the performance of clams. The findings of this study were directly compared to a nearly identical study performed nine years ago prior to the formation of the New Inlet. Throughout this study, juvenile hard clams grew fastest and adult clam condition was best in regions closer to the ocean inlets. Juvenile clam growth rates were negatively correlated with quantities of Aureococcus anophagefferens (brown tide) and positively correlated with temperature. The poorer performance of clams within central Great South Bay was related to a brown tide that occurred in the fall. The brown tide in GSB was most intense in central GSB, but was lowest in areas near inlets, suggesting that ocean flushing minimized occurrences of brown tide. The central GSB location attained higher and lower than optimal temperatures during the summer and fall, respectively. In contrast to similar experiments performed prior to the New Inlet, which observed slower growth in Bellport Bay near the New Inlet and the fastest growth in central GSB, during this study the pattern reversed. Although the sporadic occurrence of brown tides complicates the ability to draw long-term conclusions, the sum of the findings of this study suggests that the New Inlet will benefit hard clam populations by minimizing the negative effects of harmful algae and fostering ideal temperatures for growth for a longer period during the summer and fall.

Assessing the response of juvenile and adult hard clams to the new breach in Great South Bay: Post-Hurricane Sandy study

Series