More Precise Assessment of Benthic Conditions in Delaware Bay
Henry A. Walker 1, Jeff Hollister 1, Bart Wilson 2, Robert Scarborough 2 , David Carter 2, Danielle Kreeger 3, Krista Laudenbach-Nelson 3, Amie Howell 4 and Charles Strobel 1
1 U.S. Environmental Protection Agency, ORD, National Health and Environmental Effects Research Laboratory, Atlantic Ecology Division, Narragansett, Rhode Island
2 Delaware Department of Natural Resources and Environmental Control, Delaware Coastal Programs, Dover, Delaware
3 Partnership for the Delaware Estuary, Wilmington , Delaware
4 U.S. EPA Region III, Office of State and Watershed Partnerships, Philadelphia, Pennsylvania
Broad scale probability survey data from the National Coastal Assessment (NCA), and EMAP are used to: (1) help assess the overall ecological conditions in U.S. estuaries, (2) make unbiased comparisons among different estuaries in the Northeastern U.S., and (3) help determine reference conditions for more detailed studies on ecological responses & stressors in the Virginian Province (VP). The NCA surveys are often too sparse to create interpolative maps of specific benthic features. The Delaware Bay Benthic Mapping Project (DBBMP) uses a combination of synoptic acoustics and targeted sampling to create natural resource maps to be used for a wide variety of functions: (1) identifying essential fish habitats, (2) locating important locations for marine protections and, (3) locating areas of benthic habitat damage from trawling, dredging, and anchor scars. One application is identification of hard bottom areas suitable for oyster reef restoration and harvesting. We present a combined approach that uses probability survey data combined with detailed DBBMP resource maps to inform estuarine restoration and protection efforts in Delaware Bay.
Future sampling of benthic communities in Delaware Bay is planned for the summer of 2008, which will be informed by the detailed DBBMP maps generated to date. Thereafter, this effort may be expanded, contingent on funding, to a comprehensive Delaware Estuary Benthic Inventory that would identify and map ecologically and economically important physical and biological conditions and communities throughout the tidal system providing managers with broadly relevant information to guide benthic system restoration and protection.
Keywords: probability survey data, National Coastal Assessment (NCA), Delaware Bay Benthic Mapping Project, benthic communities