Entrainment of fish eggs and larvae at an operating nuclear generating station using improved methodology

Abstract Patrick PH, Di Giuseppe M, Manolopoulos H, Tai M-K, Poulton S, Wright J. 2020. Entrainment of fish eggs and larvae at an operating nuclear generating station using improved methodology. Lake Reserv Manage. 37:186–198. Entrainment data collected from 7 December 2015 to 22 November 2016 at the Darlington Nuclear Generating Station (DNGS) using automated sampling methodology are discussed in this article, including numbers of fish eggs and larvae entrained. We used a more robust sampling design than previously used in 2004 and 2006, which involved more frequent sampling over a longer, 12 month period. The design allowed collection of daily samples with a longer sampling duration and higher total sample volumes that reduced variability compared to previous studies with less robust sampling throughout a day. Our study resulted in the capture of deepwater sculpin and burbot that were not observed in previous entrainment studies. The maximum entrainment density for eggs was about 17 times higher than that for larvae. The entrainment of fish eggs was highest in the summer months (June and July) and did not vary diurnally. The highest entrainment rates for larvae occurred during the months of August and September, with higher densities entrained at night. We recommend the use of both increased sampling frequency and sampling volumes to characterize fish entrainment for water users in the Great Lakes watershed.