Closed Containment Salmon Farms
Marine Harvest Canada is well familiar with closed containment salmon farms. All our hatchery salmon are raised in closed containment tanks where they stay until they reach ten to twelve months of age. When salmon are small it is possible to used closed rearing systems; but in the ocean, it is not yet possible.
When introduced to salt water, the fish are moved to net pens at our fish farming sites along Vancouver Island and the BC mainland coast. These farm sites use tidal power to keep water circulating and to provide oxygen to the fish. This conventional rearing system requires very little electrical or fossil fuel energy input.
Conventional net pens have advanced greatly in the last ten years. They are sufficiently robust to keep predators at bay and to withstand the toughest winter storms—and to virtually eliminate escapes of our fish stock. Fish waste accumulation is minimal and regulated by provincial and federal governments. The system works extremely well and has a minimal environmental footprint.
But at the same time we are interested in new and improved technologies, such as closed containment salmon farms, that can help us manage environment risk to our fish, such as reducing the risk of ocean-borne disease, harmful plankton blooms, changes in water temperature or salinity levels and infection by sea lice.
Marine Harvest Canada invested $1.3 million in 2001 to raise farmed salmon in experimental closed containment technology which used floating closed bags at a site on Saltspring Island. Unfortunately, the results were disappointing; there were no environmental or biological advantages but operational expense was greater. Even so, we continue to investigate, encourage and fund research into closed containment salmon farms.
Serious questions need to be answered, such as the impact on animal welfare, production costs, engineering and energy requirements. After all, a land-based version of just one of our 3000 tonne production sites would require tanks that hold approximately 200,000,000 litres of water—so picture a tank measuring roughly the size of a soccer field that is 10 metres (33 ft) deep – we would need three that size. To produce the same amount of salmon we currently produce at Marine Harvest Canada annually (45,000 tonnes), we would require holding tanks equivalent to the size of 135 soccer fields at 10 metres depth. Now, consider the energy needed to keep that much water circulating, to produce oxygen, and so on.
Currently, Marine Harvest Canada and the Coastal Alliance for Aquaculture Reform (CAAR) have partnered to discuss, amongst other subjects, the economic feasibility of commercial scale closed containment salmon farms. To view the MHC/CAAR Framework For Dialogue summary click here.