Having just returned from the Seafood Summit myself I'd like to add a footnote to this story in order to explain the lack of enthusiasm for Integrated Multi-Trophic Aquaculture (IMTA) systems. Simply put, they leave major environmental impacts unaddressed.

The farming of fish in net pens in the ocean has come under scrutiny by the scientific and conservation communities for multiple reasons, the waste plume which IMTA tries to address is just one of these. An overwhelming amount of scientific research has shown that the transfer of parasites from penned to wild fish is lethal to wild salmon and trout. IMTA is unable to limit the spread of these parasites or other diseases. In the Pacific northwest wild salmon provide food for 137 species. Aquaculture that sacrifices wild salmon puts the whole ecosystem at risk. Escapes of farmed fish and the dependence on wild fish for feed for common "fed" species like salmon add additional ecological strain not addressed by IMTA.

The other species being used to control the waste of salmon and other carnivorous species are the real success story in IMTA. Mussels, abalone, scallops and sea cucumbers are types of seafood that can be grown with low inputs and little environmental impact. (A net contribution to the global fish supply that any seafood eater would be enthusiastic about.) Farmed fish, on the other hand, need to be separated from wild stocks in closed, contained systems. This is the direction that the aquaculture industry needs to take if they are truly striving for sustainability.