The Engineering Research and Development Center (ERDC) has begun a ‘range-finding’ study to determine effects of sedimentation of clean sediment on winter flounder eggs and early life stages. A major concern cited is the generation of suspended sediments near dredging operations to which a wide range of adverse effects, including fish migration spawning, oyster and clam survival and reproduction and aquatic plant survival, have been attributed.
Species restricting project dredging operations are used to show how specific suspended sediment data can be used to more plausibly set EWs for specific areas where dredging operations routinely occur. These experiments are conducted in the Fish Larvae and Egg Exposure System (FLEES), a dedicated modular and flexible flow-through exposure facility that delivers consistent suspended sediment concentrations in multiple experimental aquaria. The study endpoints can be varied to meet study objectives (e.g., survival, hatching success, growth, etc.) and to specifically address species and life stages used to set EWs.
As part of this study ERDC staff administered an online survey to collect information from stakeholders (resource managers and project managers) in the New England Region about appropriate range finding approaches to use in the study. The results of this survey were presented at two webinars on December 5 and 11, 2015
During discussions of the context of effects studies, the participants referenced several key studies conducted recently. These include a study of winter flounder eggs and larvae by Walter Berry and URI scientists and two studies conducted in New York Harbor by Dara Wilber and colleagues [Wilbur et al. juv, and eggs].
Winter flounder (Pseudopleuronectes americanus) in Narragansett Bay. Credit: Jerry Prezioso, NEFSC/NOAA
Percent total hatch of winter flounder eggs from three experiments (top), and length of time to hatch (bottom) at various sediment exposure depths. (Figure courtesy of Wendell Berry)
ENSR. 2008. Providence River and Harbor Maintenance Dredging Project Synthesis Report. DAMOS
Contribution No. 178. U.S. Army Corps of Engineers, New England District, Concord, MA, 133 pp.