Typhoons have been a challenging issue for fish farms in South Korea. In 2012, the waves, winds and currents of three successive typhoons destroyed every fish farm in South Korea except for Insung’s floating copper-alloy mesh pens. Surprisingly, the copper-alloy mesh pens had the strength and stability to survive the typhoons. This caught the attention of the Korean government and some innovative thinkers who decided that submerged pens would be even better at protecting the fish.
In 2011 South Korea imported about 22,000 tons of salmon (over 5 million fish) and caught some 437 tons of salmon in coastal waters. Demand for salmon continued to rise. Aquaculture technology company OceanSystec saw an opportunity to replace imported salmon with local production. Salmon thrive in water temperature less than 20°C, but the water around Korea often exceeds 29°C in the summer. OceanSystec decided to develop a submersible pen to get to cooler subsurface water. The pens required other important qualities: the ability to survive typhoons, the ability to stay clean without maintenance by divers, and the ability to maintain their volume in strong currents. OceanSystec knew that copper-alloy mesh offered these qualities and contacted ICA about developing submersible pens.
Research conducted in Norway demonstrated that salmon could be submerged for up to 17 days without problems, but submerging salmon for a long time had never been tried commercially. With support from ICA, OceanSystec spent $3 million of their own money and about $6 million from the Korean government to develop and deploy ten prototype pens. These pens were installed by fish farmer Donghe STF, and further development took place. The pens were submerged 25 meters below the surface to keep the water temperature between 15 – 18°C year round and to avoid the wild sea conditions common during typhoons. Dohghe STF learned a variety of skills, from when to bring the salmon to the surface so they could fill their swim bladder to how to raise the salmon without antibiotics.
In 2017 South Korea became the first Asian nation to successfully raise salmon throughout the year, producing 500 tons of salmon in Dohghe STF’s submerged pens 5 kilometers off the east coast of Gangwon County. Due to excellent results, the company plans to install 36 additional pens.
The Korean government stepped in again to support a detailed environmental impact study and to consider how to expand copper-alloy mesh pens to other species such as sea bream. Additionally, the government changed the aquaculture regulations so that major corporations, not only small family fish farmers, could invest in offshore fish farming.
Now the Korean Ministry of Ocean and Fisheries is urging fish farmers to use copper-alloy mesh in submersible offshore pens to expand fish production. The Gangwon Daily reported that successful salmon farming (in submersible copper-alloy mesh pens) could produce 20,000 tons of salmon yearly in offshore pens and add US $2.5 billion/year to the region’s economy. Because of this analysis, Gosung province has decided to establish the Gosung Salmon industrial zone and aims for annual production of 100,000 tons of salmon.
Copper-alloy mesh is a key enabling technology for offshore aquaculture and can be a substantial driver of economic development and food security.