Atlantic salmon farming companies are designing huge pens to raise fish in the open seas in a radical shift from calm coastal waters where marine lice have slowed growth of the billion-dollar industry.
The drive for new designs by Norway, producer of 54 percent of all farmed Atlantic salmon in 2016, will have to cope with ocean storms that can rip cages and free thousands of fish.
Escapees disrupt natural stocks by breeding with wild cousins.
“The industry has to develop and to solve the environmental challenges it has, especially linked to salmon lice,” Norwegian Fisheries Minister Per Sandberg told Reuters, referring to parasites that often spread infections resistant to antibiotics.
One in five salmon farmed in Norway dies before reaching maturity, partly due to tiny blood-sucking lice that latch onto the outside of the pink fish.
Lice, also a problem in other countries, tend to concentrate in the more stagnant waters of Norway’s bays and fjords where farms are now based. A shift offshore would expose farms to ocean currents that should help to sweep away the lice larvae.
The Norwegian Directorate of Fisheries is seeking innovative fish farm designs, both for offshore and coastal waters, in a two-year drive open until November 2017. So far it has approved a handful and is reviewing about 40 others.
Many borrow ideas from the offshore oil and gas industry.
The lure of offshore pens is that they would open almost unlimited areas for fish farms beyond bays and fjords, attracting investors and transforming the global aquaculture industry.
Norway produced 1.1 million tons of salmon in 2016, more than double the output of number two producer Chile, and earned $7.6 billion in exports. Smaller producers include Britain, the Faroe Islands and Canada.
But Norway’s production, by companies including Marine Harvest, SalMar and Leroy Seafood, has been little changed since 2012 due to lack of space and disease, even as rising demand has pushed prices to record highs.
“We’ll take the project that works best, has no salmon lice, the lowest cost, no escapes and is industrial,” Marine Harvest’s chief executive officer Alf-Helge Aarskog told Reuters of a range of designs the company has proposed.
Nets in coastal farms sometimes tear in storms, harming wild stocks from Scotland’s Spey River to Norway’s Alta River, and offshore farms will be exposed to far stronger winds and waves. Last year, 126,000 salmon broke out of Norwegian farms.
“Escaped fish mix with the wild salmon – that creates problems with genetics,” said Ingrid Lomelde, of the WWF Norway Farmed fish are bred to grow fast and fatter than their sleek wild cousins. Interbreeding could produce fish too weak, for example, to leap up waterfalls to reach spawning grounds.
Among approved designs, SalMar is building what it calls the “world’s first offshore fish farm” to start in late 2017 — a floating circular construction 110 metres (360 ft) across that looks like a drilling…