Generator Cooling Water Effluent Restriction Effects of Oyster Creek Generating Station Closure on the Barnegat Bay Fish, Crab, and Infaunal Invertebrate Community



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Trenton, N.J. : Department of Environmental Protection, Division of Science and Research


Closure of the Oyster Creek Nuclear Power Generating Station in Forked River, Lacey Township, NJ, in September of 2018 resulted in a 95% reduction of cooling water flow. Since cooling water was drawn from and discharged back into the Barnegat Bay near Barnegat Inlet, the historical effluent plume heated water with the potential to affect the thermal ecology of cold-blooded fish and invertebrates. The cooling water pumps also entrained larval fish and crabs directly and thus potentially affected the mortality of select species in the bay’s larval source pool. The effluent plume secondarily affected stratification and flow in the area through production of a warm, low-density, plume . Closure allowed a retrospective examination of these potential effects as well as provided a model for the sensitivity of the local fish and invertebrate community to climate change. This study leveraged previously collected samples of fish, crabs, and invertebrates from as far back as 2012 for comparison with recent sampling (2018-2021) in a Before/After Control/Impact design (for fishes and crabs) or a Before/After/Gradient design (for benthic infauna) to challenge the null hypothesis that there was no effect of closure and to quantify any noted effects relative to natural variation. Measures included abundance/distribution (for fishes, crabs and benthic infauna), assemblage change/beta diversity (for fishes and invertebrates), and size (for fishes) at different life stages as sampled by plankton net, otter trawl, crab traps, and gillnets. The strength of effects and the confidence in their measure was dependent on species and life stage, and for some there were no measurable effects. In all cases, BACI/BAG interactions (effects measured as different after closure in the Impact sites relative to their measure in the Control sites) were secondary to other sources of variation, including habitat, seasonal, and interannual variation, and spatial variation among the control sites. It is apparent that control site choice, as a function of measurement scale, affects the answer, pointing to a recognized and fundamental challenge in ecology. In retrospect, the plant was well sited because the spatial extent and persistence of the plume effects were dampened by regular tidal exchange with the ocean through Barnegat Inlet. Measured effects on sex-specific crab distribution and benthic invertebrate distribution and abundance decreased rapidly with distance from the discharge. Abundance was never seriously depressed (and was increased for adult fish) during operation in the Impact site, most likely because it was never source limited. Fish, benthic infauna, and many of the crabs utilizing the bay arrive from distant spawning sites as larvae, and many of the adult stages arrive as migrants; thus, local consumption by the plant was mitigated. Further, the life history of these species are adapted to and experience, individually and as populations, a greater annual and range-wide thermal variation than that produced by the generating station. This is a function of the station’s location near the apex of the Middle Atlantic Bight, and should be expected to differ from similar power-plant cooling water disturbances elsewhere in the country or world.



New Jersey, Oyster Creek Nuclear Generating Station (N.J.), Fishes - New Jersey - Barnegat Bay, Crabs - New Jersey - Barnegat Bay, Invertebrates - New Jersey - Barnegat Bay



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