September 25, 2018 — On a projection screen in front of a packed room in a coastal Maine town, computer-animated salmon swim energetically through a massive oval tank. A narrator’s voice soothingly points out water currents that promote fish exercise and ideal meat texture, along with vertical mesh screens that “optimize fish densities and tank volume.” The screens also make dead fish easy to remove, the narrator cheerily adds.
The video is part of a pitch made earlier this year for an ambitious $500-million salmon farm that Norway-based firm, Nordic Aquafarms, plans to build in Belfast, Maine, complete with what Nordic says will be among the world’s largest aquaculture tanks. It is one of a handful of projects in the works by companies hoping these highly mechanized systems will change the face fish farming—by moving it indoors.
If it catches on, indoor aquaculture could play a critical role in meeting the needs of a swelling human population, Nordic CEO Erik Heim says. He believes it could do so without the pollution and other potential threats to wild fish that can accompany traditional aquaculture—although the indoor approach does face environmental challenges of its own. “There’s always some risk, but the risk of the land-based system is a small percentage of the risk of an outdoor system,” says Michael Timmons, an environmental engineer at Cornell University who has studied aquaculture for more than 20 years and is not involved in the Nordic project.
Fish farming has often been touted as an extremely efficient way to produce animal protein: the Global Aquaculture Alliance claims 100 kilograms of fish feed can deliver up to 15 times more meat than an equivalent amount fed to cows. The industry has gained international traction, with farmed fish surpassing wild-caught ones (pdf) in the global food supply in 2014. But traditional fish-farming methods come with significant environmental drawbacks. For example, salmon farmers in Norway and Chile—the world leaders in salmon production—typically use open-ocean cages that corral fish in suspended netting or pens. This setup allows waste to flow directly into the environment, along with pathogens and parasites that can infect wild populations. Open-air pond farms—found worldwide and representing the most common type of aquaculture in China, the top global producer of farmed fish—also have a track record of polluting local waterways with fish effluent and veterinary medicines that are used to keep disease at bay.