Copper Alloy Fish Cages

Salmon farming is a multi-billion dollar global industry facing considerable difficulties posed by growing pressure from environmental regulatory bodies. Because marine organisms grow on and "foul" synthetic nets, oxygen available to fish is reduced and infectious diseases and parasites can spread among the fish. The combination of copper alloys' antifouling, antibacterial properties, and mechanical strength leads to healthier fish without antibiotic use, prevents the escape of farmed fish due to attacks by marine mammals, and can reduce production costs by up to 30%. Copper alloy nets are completely recycled at the end of their useful life.

Researchers around the world are studying the benefits of using copper alloys as a material for salmon farming nets and as nets for other species.

Copper alloys' antifouling and antibacterial properties create a healthier aquaculture environment within the net, lessening the industry's reliance on antibiotic use to control disease. If brass, a copper alloy, is used in place of synthetic material, marine organisms will not become attached to the nets. This will control the spread of infectious diseases by eliminating the fouling environment in which pathogens and parasites that infect fish can thrive. Also, without fouling, clean, oxygenated water can reach the fish. Research has shown that fish in copper alloy enclosures grow faster and require less food.

During the summer, synthetic nets can foul to the point where they must be changed within a few weeks. Copper alloy nets do not foul over the entire 18 month period of salmon growth from smolt to harvest. Avoiding the need to change nets provides a big simplification in farming operations.

An added advantage of copper alloys as the material of choice for salmon farming nets is its ability to prevent sea-lion attacks, which cost the industry millions of dollars in lost revenue each year. The mechanical strength and resilience of the copper alloy net makes it impenetrable to predators such as sea lions and prevents fish within the cage from escaping into the open ocean through holes made by predators. Also, unlike nets made of synthetic materials, copper alloy nets are completely recyclable at the end of their useful life.

There has already been some commercial application of copper alloy nets in Japan and Australia with excellent results. Activities in Chile, the leading salmon producing country, are just starting.