Additional reporting by Bonnie Waycott

Sea cage makers and copper producers are on the verge of delivering an important disruption to the global aquaculture industry. 

Copper, which prevents biofouling because of its antimicrobial properties, can be used in aquaculture cage netting and makes sea pens stronger and capable of withstanding hurricanes and typhoons. Copper alloy mesh could make aquaculture feasible in areas of the world that suffer big storms, such as the South China Sea and the Mediterranean. 

German copper materials maker Wieland has slowly bided its time with an aquaculture investment, patenting cage mesh technology in 2015, and acquiring a handful of customers in Australia, China, and Hawaii. The company is in the process of convincing Norway’s salmon farmers to use the technology, said Daniel Steitz, Weiland's head of innovation at BU EX bei Weiland Group. 

“The aquaculture industry is now facing a situation where it is going more and more offshore, and we see more and more benefits for our material,” Steitz told Undercurrent News.  

Wieland’s incursion into sea cages is part of a broader trend of innovators from other industries targeting the high-growth aquaculture industry, bringing solutions to key pain points. The Ulm, Germany-based company is the world’s largest maker of copper alloys, producing over 180 materials for thousands of products.  

Brass is the alloy of copper and zinc and has been used since Ancient Greece. Copper, besides being tougher than nylon or polyester nets, is antimicrobial and prevents biofouling. This prevents the accumulation of microorganisms, plants, algae, barnacles and mollusks, that tend to accumulate on traditional nylon netting and limit the flow on water into a cage. 

Biofouling on nets was deemed as the cause of the Cooke net pen collapse in the Puget Sound in 2017, where 200,000 Atlantic salmon escaped, allegedly affecting wild salmon river runs. Cooke reportedly hadn’t had time to carry out maintenance on the nets since it bought the assets from troubled Icicle Seafoods the year before. 

Wieland is not alone in looking to apply antimicrobial copper in aquaculture. The International Copper Institute in South Korea has been researching copper cages for several years to develop an aquaculture industry around the Korean peninsula, said country manager Chris Lee. Prototype cages have been tested by STP Donghae, an offshore salmon farmer in South Korea. The Asian country has ambitions to farm bluefin tuna and the technology will help them in that quest, Lee said. 

Copper mesh is a much more expensive component than traditional plastic but comes into its own in new submersible pen designs, as it solves the problem of needing to frequently clean nets. Donghae needs to submerge cages for several weeks during the Korean summer when surface temperatures can approach 30 degrees Celsius (86 degrees Fahrenheit) [...]