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US EPA WINTER FLOUNDER PROJECTS AND OTHER WORK IN RHODE ISLAND SALT PONDS
Citation:
Cicchetti, G, M Chintala, R J. Pruell, L Meng, AND B K. Taplin. US EPA WINTER FLOUNDER PROJECTS AND OTHER WORK IN RHODE ISLAND SALT PONDS. Presented at SeaGrant Symposium on Shallow Water Marine Ecosystems of South Rhode Island, URI Coastal Institute, Narragansett, RI, January 15, 2002.
Description:
We will briefly summarize selected EPA research in Rhode Island's salt ponds from 2000 through 2003. In one project, during the summer of 2000, we used a 1.75 m2 drop sampler to quantify populations of juvenile flatfishes and other small nekton in Ninigret Pond. Mean abundance of all fishes in the sampled habitats was high, at 21.8 + 2.1 (SE) inds/m2. The mean abundance of juvenile winter flounder (15 - 95 mm) in all habitats was also high at 11.0 + 2.2 (SE) inds/m2. These data, and the work of others, point to the importance of Rhode Island's coastal lagoons as valuable fish nursery habitat. Motivated by these findings, we are planning a larger winter flounder study in 2003 to investigate juvenile flounder/habitat relationships in several of the salt ponds, in the West Passage of Narragansett Bay, and in the Providence River. The major goal of this study will be to develop empirical relationships between habitat characteristics at several scales and fish densities, as part of an EPA effort to characterize habitats for development of habitat protection criteria. Habitat characteristics will be assessed in 2003 with an instrument sled equipped with digital and analog video cameras and a continuously recording YSI instrument logging T, S, DO, depth, optical Chl-a and turbidity. The sled also includes a beam trawl used to simultaneously estimate fish densities. We will also acquire aerial photographs of our sampling sites to correlate underwater and shoreline habitat arrangements with fish densities at larger spatial scales. This gear was tested in Narragansett Bay in 2002; we look forward to using these techniques in the salt ponds. Other flounder work planned for the salt ponds in 2003 will attempt to evaluate the relative contributions of juvenile habitats to fished adult flounder populations using otolith microchemistry. This work focuses on identifying distinct chemical signatures in juvenile flounder otoliths from macroalgal, seagrass, and unvegetated habitats in the salt ponds and in Narragansett Bay. Preliminary work showed that carbon isotope ratios of otoliths from juvenile flounder taken from three of the salt ponds were different from signatures of flounders taken from similar habitats in Narragansett Bay. If habitat/location combinations can be successfully identified in juvenile otoliths, we will then examine the central cores of otoliths from fished adult populations for these same signatures, so as to assess the relative contributions of distinguishable juvenile habitats to the adult populations. Finally, we will also describe EPA's National Coastal Assessment work in the salt ponds.