Fish aquaculture production on an intensive scale has
caused many environmental problems (Wu 1995; Chopin
and Yarish 1998). Modern intensive monoculture
requires high inputs of water, feeds, fertilizers and
chemicals and inevitably produces considerable wastes.
Therefore, many aquaculture operations put enormous
pressure on coastal habitats (Chopin and Yarish 1999;
Black 2001). Waste products from fish farms consist
mainly of nitrogen, phosphorus and carbon dioxide. In
pen-based salmon aquaculture, the production of one