Abstract.-Derelict (abandoned or lost) traps targeting blue crab Callinectes sapidus have the potential to affect the blue crab fishery and other marine-oriented species. We used sidescan sonar to locate derelict traps and assess their extent and accumulation rate. Experimental traps were monitored at four locations to calculate catch rates of marine organisms and trap degradation rates. In 2006, 635-676 derelict traps were identified in a 33.5-km 2 area of the lower York River in

We propose a regional classification for wetlands of the Mid-Atlantic region, USA. It combines functional characteristics recognized by the hydrogeomorphic (HGM) approach with the established classification of the National Wetland Inventory (NWI). The HGM approach supplements the NWI classification by recognizing the importance of geomorphic setting, water sources, and flow dynamics that are key to functioning wetlands. Both NWI and HGM share at their highest levels the Marine, Estuarine, and Lacustrine classes. This classification departs from the NWI system by subdividing the Palustrine system into HGM classes of Slope, Depression, and Flat. Further, the Riverine class expands to include associated Palustrine wetlands, thus recognizing the interdependency between channel and floodplain. Deepwater habitats of NWI are not included because they differ functionally. Mid-Atlantic regional subclasses recognize two subclasses each for Flat, Slope, and Marine Tidal Fringe; three subclasses for Depression; four subclasses for Lacustrine Fringe and Estuarine Tidal Fringe, and five subclasses for Riverine. Taking a similar approach in other geographic regions will better characterize wetlands for assessment and restoration. This approach was applied successfully during a regional wetlands condition assessment. We encourage additional testing by others to confirm its utility in the region.

No abstract

A study to determine the effects of the Chesapeake Bay oil spill of February 1976, and of the subsequent cleanup operations was conducted on the eastern shore of the Bay. The primary objective was to assess the biological impact on the marshes at the population level. Populations of intertidal mussels, Modiolus demissus, and oysters, Crassostrea virginica, showed no significant short-term effects. The population of the snail, Littorina irrorata, was significantly reduced, but appears to be recovering well. The dominant marsh grass Spartina alterniflora showed increased net productivity as measured by standing crop, increased density, decreased mean height, and increased flowering success. Hypotheses to explain these observations are discussed. The impact of the spill on the marshes is thought to have been minimized by virtue of the relatively low toxicity of the oil, the time of year the spill occurred, and the comparatively high energy environment of the shoreline. (VIMS contribution number 718)

Abstract:The relationship between ground-water fluctuations and the canopy compositions of five tidal freshwater swamps were examined. Tide gauge data were comparcd with measured ground-water fluctuations to assess the role of tides in driving the hydrologic regimes of tidal swamps. Flooding in tidal swamps was found to be closely associated with high tidcs. As the tides dropped through the hummock zone (elevated area, about 15 cm high, to which the trees are restricted), drainage of the hollows (low areas between hummocks) occurred at the same rate as the falling tidcs. After the tides dropped below the elevation of the hollows, the lowering of the water table became much slower than that of the falling tides, presumably because peat in the root zone inhibited drainage. When the subsequent rising tides reached the elevation of the water table, the water table rose vertically with the tides. Flooding recurred in the hollows as the tides rose above the surface of the ground. The composition of the canopy was found to be related to the mean water-table depth (WTD) (i.e., the depth in relation to the hummock elevation at which the soil was flooded 50% of the time) and not to the duration, depth, or frequency of flooding. Tidal swamps dominated by Fraxinus spp. and Nyssa sylvatica var. b(/lora occurred in the wetter sites (mean WTD -17 cm), whereas swamps dominated by Acer rubrum and Liquidambar styracijlua occurred in less wet sites (mean WTD = 21 to 30 cm). Tidal freshwater swamps arc precariously positioned at the upper portion of the tidal range where they seem to keep pace with a rising sea level by accumulating biomass (logs and roots). Potential threats to the distribution and areal extent of tidal freshwater swamps include any abrupt changes in the rate of sea-level rise, periodic logging, or blockage of their upriver migration due to incompatible land use.