Mr. Tollefsen, who also serves on the technical advisory committee of the Peconic Estuary Program, has been dedicated to the idea of returning East End waters to their former shellfish and finfish production levels. The algae, in turn, are eaten by filter-feeding shellfish. The shellfish thus inherit the nitrogen. When enough finfish and shellfish consume the nitrogen-fed algae, the food chain is balanced and the water stays clear. If too much algae grow because of an overabundance of nitrogen, or because there are not enough shellfish to consume it, the water is robbed of oxygen.
Fish kills can be the result.
Nutrient Loss What has not been taken into consideration in other hypotheses, Mr. Tollefsen said, was the amount of nitrogen being taken out of the Peconic system along with the shellfish. In 1910 they took 1.7 million bushels of oysters out of the Peconic system. In addition, the Peconic estuary once produced one-third of all the bay scallops in the country. But, Mr. Tollefsen said, when shellfish were being harvested abundantly, nutrients also were being removed at record levels - an estimated 500,000 pounds of nitrogen in 1910 alone. As early as the 1950s, efforts to reduce the amount of nitrogen and other pollutants in surface waters by controlling wastes from duck farms, sewage treatment plants, septic systems, and more recently by controlling road runoff were under way.