WATER-QUALITY ASPECTS OF OFFSHORE FISH FARMING

The aquaculture industry has developed significantly over the past two decades. In the 1970s, fewer than 3000 t of Atlantic salmon were farmed globally per annum while the 1991 harvest was in the region of 253 000 t. This industry has developed along coastlines such as the west coasts of Scotland and Ireland, and as a result has contributed to the socio-economic maturity of such marginal areas. However, large-scale fish farming activities can have significant environmental impacts; therefore, it is necessary to ensure that, while the industry continues to grow and develop, the impacts on the environment are minimized and kept within acceptable limits. In this Paper, various techniques that have been used to quantify some of the environmental impacts due to offshore aquaculture activities will be discussed. In particular, the mathematical formulation of two-dimensional hydrodynamic and dispersion models and the application of such models to assess the environmental impact of a salmon farm off the west coast of Ireland will be discussed.