The application of simple models of nutrient loading and oxygen demand to the management of a marine tidal inlet

Human developments in the Letang, a macrotidal inlet of the Bay of Fundy, include salmon aquaculture, traditional fisheries, fish processing plants, a pulp mill, and a municipal sewage treatment plant. All of these are sources of nutrients and oxygen demand. Inputs from these sources are evaluated, and simple models are used to compare environmental effects as well as to assess changes in use patterns or possible future growth. Wastes from salmon aquaculture and fish processing are the dominant anthropogenic inputs to the Letang. Recent improvements in equipment and operations at the pulp mill as well as one fish plant have lessened their environmental impact. Anticipated expansion of the aquaculture industry would increase nutrient enrichment and oxygen demand in the local environment. The combination of input evaluation and simple models can provide a holistic management tool for coastal environments with competing multiple uses.