Aquaculture from a different angle: the seaweed perspective, and the rationale for promoting integrated aquacultur

Aquaculture, especially in the Western World, is very often conducted in a monotypic manner without employing a balanced approach for long-term sustainability, which would take into consideration the assimilative capacity of the ecosystem. To develop innovative, effective and responsible practices ñ maintaining the health of coastal waters, and, consequently, of the cultured organisms ñ fed aquaculture types (e.g. finfish, shrimp) and organic or inorganic extractive aquaculture types (e.g. shellfish or seaweed) need to be integrated to avoid pronounced shifts in coastal processes. Most impact studies on aquaculture operations typically have focused on organic matter/sludge deposition. However, the inorganic output of aquaculture is presently emerging as a pressing issue as nutrification of coastal waters is a worldwide phenomenon, which has not spared the Bay of Fundy (Chopin et al. in press). Conversion, not dilution, is the solution so that the ìwastesî of one resource user become a resource (fertilizers) for the others. It can frequently be heard that the development of ìalternativeî species will reduce some of the aquaculture impacts. Unfortunately, too often ìalternative speciesî in the minds of a lot of people means ìalternative speciesÖ of fishî. Even though introducing another species of fish may add up economically in the short term, rarely does it balance energetically and environmentally in the long term. It is still fed aquaculture, with extra, unconsumed, pellets and unidirectional metabolic excretion. For a balanced ecosystem approach what is needed is a diversity of co-cultured organisms, performing different processes throughout the day and seasonally, and an estimate of the proportionate biomass of each so that their metabolic processes compensate each other.