The technology, scale and physical spaced needed to farm fish and shellfish in our coastal waters make aquaculture an unsustainable activity.
Production of farm-raised fish looks remarkably similar to production of cattle, hogs or chickens in confined animal feed operations (CAFOs) or industrial livestock operations (ILOs). Such animal operations rely on manufactured feed, medications to prevent or treat diseases and parasites which are an unavoidable result of stressed animals kept in unnatural conditions, and concentrated volumes of polluting waste products which become serious environmental and health problems.
Oyster and mussel farms have become so large as to occupy significant portions of entire bays. In areas where this has occurred, the overall ecological productivity of the bays has been diminished. According to scientists, the potential impacts of shellfish aquaculture on the environment include: changes in the flow of matter and energy as a result of releases of nitrogen and pseudofeces; exposure of wild populations to infectious diseases and pathogens; introduction of invasive species; depletion of phytoplankton; shifts in phytoplankton size and formation of algal and macroalgal blooms; and changes in the movement of water (local currents) due to suspended nets, bags and lines.
Further, fish and shellfish farming are taking place on the very grounds that have supported commercial wild fisheries for centuries. Traditional fishing and harvesting activities have been displaced to make room for fish and shellfish farms. Community conflicts have arisen around the use of public beaches as staging areas for aquaculture. Noise and light pollution from from farm sites have disturbed coastal land owners.
In order for aquaculture to be sustainable, it must not discharge untreated waste and chemicals into waterbodies; it must not depend, in the case of finfish aquaculture, on wild fisheries as a source of feed; it must not allow farmed species to escape into the wild; it must not displace existing activities; and it must not get special treatment from regulators.