The Pamlico River Estuary extends some 35 miles from Washington, N.C. to Pamlico Sound. It is shallow, from 2 to 6 miles wide, naturally productive, and has from 0.5 to 15 or 20 ppt salinity. The salinity regime is determined chiefly by the quantity of inflowing freshwater and changes in salinity of up to 10 ppt are common at any station. Lunar tides are small (less than 0.5 ft) but wind and wind tides can have important effects on the salinity distribution. In addition, the Coriolis Force causes much of the freshwater to flow along the south side of the estuary. The temperatures range from 3C (37F) to 34C (93F), although temperatures above 31C (89F) are unusual. On any given day, there could be horizontal temperature differences of up to 4 degrees (C) or 7 fahrenheit degrees. The estuary stratifies irregularly; when this happens in the summer complete deoxygenation may occur. This condition may last for only a week and then be destroyed by wind. The benthic animals (bottom dwelling) are completely eliminated from large stretches of the river by the low concentrations of oxygen. (WRSIC abstract)