Net drift in an atypical estuary, Long Island Sound
Long Island Sound is an estuary with two-layered flow at the eastern opening to the ocean and a salinity gradient of about 5 parts per thousand between the eastern and western extremes. Tidal currents, wind-driven circulation, and river inflow and fresh water influx are investigated as factors affecting the net drift. Current measurements in eastern Long Island Sound indicate that the tidal circulation features that predominate there do not normally affect the net drift at the New Haven dump site. Drifter returns and a numerical model indicate that seasonal prevailing winds seem to be the primary cause of the net drift in central Long Island Sound.
Determining Winter flounder Spawning Sites in Two Connecticut Estuaries
Abstract Winter flounder ( Pseudopleuronectes americanus ) come inshore during the late winter and early spring to lay their eggs in shallow bays and estuaries along the coast. Unlike most fish eggs, which are buoyant, these eggs are demersal and sink to the seafloor. This makes them vulnerable to burial from various types of natural and human-caused disturbances (e.g., storms, mobile fishing gear, maintenance dredging). Our objective was to map spawning areas in two harbors and search for generalities among these sites that would allow us to predict where winter flounder might spawn in other areas. This would allow managers to avoid permitting activities for those times and locations where winter flounder spawn. We used a modified demersal plankton net (a benthic sled) to collect winter flounder eggs in New Haven and Milford harbors and map their distributions. Most of the eggs were collected at the end of March, when water temperatures were 4-6 ° C. This could vary from year to year depending on temperature. The distributions of eggs were not correlated with sediment type or depth but were related to the prevailing tidal currents in the area sampled. Since the eggs are present in low-current depositional areas, they are vulnerable to burial. Our observations suggest that winter flounder either do not deposit eggs in high current areas, or if eggs are deposited there, they are swept away
Salinity variations in the Connecticut River
Salinity distributions in the lower Connecticut River, measured during the years 1934 through 1939, show the influence of at least three factors: river discharge, tide, and wind. Salinity near the mouth is rather sensitive to changes in upland discharge; discharge events recorded at a gage 101 km upstream are followed a day or two later by markedly equivalent changes in salinity at the mouth. During average or greater-than-average discharge conditions the lower river has the characteristics of a ‘salt-wedge’ estuary: the water on the bottom of the river may contain 15 parts of chloride per thousand at high tide, whereas the water in the same section of the river at low tide may be almost completely fresh. The effects of winds on salinity are uncertain, but such effects can be either local or related to regional effects of winds on the tides at the river mouth. (Key words: Estuaries; sea water; Connecticut; tides)