ABSTRACT
The results from this study are consistent with the conclusions of Ginzburg and Ferson[5]. Measurement error at the level generated from indices of abundance for juvenile striped bass in the Hudson River (50%) had a significant effect on risk. When all of the variation was assumed to be natural and, thus, there was no measurement error, the probability that recruitment would fall below the 20% threshold overestimated risk about tenfold after 15 years. Overestimates of this magnitude could produce conservative impact assessments and require costly efforts to reduce entrainment mortality that may not measurably reduce risk. Accurate estimates of risk are necessary but not sufficient for defining AEI. A change in risk should be related to a previously established benchmark, such as the one provided by Amendment #5 to the Interstate Fishery Management Plan for Atlantic striped bass. Amendment #5 recommended an increase in F from 0.33 to 0.40, which had about the same effect on the risk of a decline in recruitment to the Hudson River stock of striped bass as an increase in CEMR from 0 to 11%. Thus, if sustainability of the Hudson River stock of striped bass is not reduced by the change in risk associated with the increased fishing mortality, it is not reduced by the change in risk associated with entrainment. It is important to know if sustainability of the Hudson River stock of striped bass would be reduced if consecutive SPDES permits were issued to the Bowline, Indian Point, and Roseton power plants for a period of up to 15 years. Although risk increases with time, the differences in risk among time horizons of 5, 10, or 15 years were smaller than the uncertainty associated with the estimates of risk when measurement error was equal to 50%. If the estimate of measurement error based on juvenile striped bass in the Hudson River (50%) corresponds to the level of measurement error for age-1+ fish, consecutive discharge permits should not reduce sustainability of the Hudson River stock.
