Entrainment Survival of Fish Eggs at Two Long Island, NY, Generating Stations

Entrainment survival, the ability of planktonic organisms to pass through a power plant cooling system alive, can be an important concept to consider in evaluating Best Technology (BTA) for compliance with §316(b) of the Clean Water Act.  In 2011, National Grid sponsored a study of entrainment survival at the E.F. Barrett and Northport Generating Stations.  Sampling occurred from late April to late July at both stations. Samples were collected simultaneously at the intake and at the discharge and spanned a wide range of plant operating and thermal discharge conditions. At both stations fish eggs were highly abundant in samples, and most common species were Bay Anchovy, Cunner, and Tautog.  Observation times up to 8 days resulted in some difficulty in identifying unhatched eggs, particularly at Northport.  Entrainment survival was estimated for 11 species/life stage combinations at Barrett and 8 at Northport.  Entrainment survival estimates at temperatures below those causing thermal stress, based on Failure Time Analysis, at Barrett and Northport respectively were: Bay Anchovy eggs (0.70 and 1.00), Cunner eggs (1.00 and 1.00), and Tautog eggs (0.89 and 0.91).  At Northport, estimated entrainment survival of all fish eggs combined, which included the unidentified eggs, was 0.72.