In February 2022, a Dutch-owned fishing trawler released a silvery stream of 100,000 dead fish, which carpeted several thousand square metres of ocean off the coast of France. The vessel’s owners blamed the discharge on a faulty net. Environmental groups alleged that the fish were intentionally dumped. Whatever the truth, that spectacle of squandered sea life was the tip of the iceberg: figures from WWF show that in 2019, at least 230,000 tonnes of fish were dumped in EU waters. Most of the waste – 92% – is related to bottom-trawling, a fishing method that scrapes the seafloor, indiscriminately scooping up everything in its path. But this figure is a small fraction of an even larger global issue. The UN Food and Agriculture Organization (FAO) estimates that 35% of all fish, crustaceans and molluscs harvested from oceans, lakes and fish farms are wasted or lost before they ever reach a plate. Fish are highly perishable and fragile, which makes them more vulnerable to waste, a problem that is compounded by haemorrhaging fish at every step of the supply chain. Fish waste is especially shocking, says Pete Pearson, senior director for food waste at WWF, because they “are wild animals, so we are harvesting wildlife”. Fish populations are already threatened by overfishing, pollution, and the climate crisis. With current rates of fish consumption projected to double by 2050, waste is increasingly on the radar of regulators. “We have to do something about it,” says Omar Peñarubia, a fisheries officer at the FAO. That begins, experts say, with understanding exactly what is driving waste between harvest and plate. The task is made difficult by fisheries’ notoriously opaque supply chains, and incomplete datasets that are also inconsistent, although the evidence is clear that most fish waste starts at the point of extraction. Just under half of all fish consumed by people is wild-caught at sea. “There’s such abundance that we’ve grown to be OK with certain loss rates,” Pearson says, although noting that 34% of global marine stocks are now overfished. Bycatch (unintentionally caught, unwanted fish) is a growing problem, too: roughly 10% of wild-caught fish are discarded worldwide each year, representing 8.6m tonnes of animals. The main culprits are imprecise fishing gear and policies that allow fishers to discard non-target species. There’s an economic driver, too. “I think there is a strong connection between subsidies and waste in the water,” says Rashid Sumaila, professor of ocean and fisheries economics at the University of British Columbia. Although subsidies were historically devised to support small-scale fishers, today 80% of $35.4bn (£26.4bn) in annual fishing subsidies goes to a handful of industrial fleets, Sumaila’s research shows. These include gargantuan bottom trawlers that are uniquely equipped to travel out to the high seas and overfish, leading to discards on an industrial scale. The impact of illegal and unreported fishing is also important, says Sumaila, as it is likely contributing tonnes more bycatch to global fish waste. Food for 3 billion people Fish waste is about more than just the physical loss of fish: for the 3 billion people whose diets depend on fish, it is a lost nutritional opportunity. “The narrative is that we have to produce more to feed the growing masses, but the greatest pathway to [increasing] supply is reducing loss and waste,” says Shakuntala Thilsted, global lead for nutrition and public health at World Fish and winner of the 2021 World Food Prize. Many see controlled aquaculture systems (or “fish farms”) – which generate more than half our fish supply – as a solution to the waste of wild fishing. But Dave Love, senior scientist at the Johns Hopkins Center for a Livable Future, says that various factors, such as disease, are driving considerable losses on farms, too. “Mortality in fish ponds is actually a significant source of lost potential food,” Love says. Fish waste continues after harvest – though how it unfolds differs depending on location. The FAO estimates that 27% of all fish globally is lost or wasted after landing, but in low-income countries the fish is more likely to be unintentionally lost than wasted, says Peñarubia. One study showed that in Ghana, Burkina Faso and Togo, 65% of lost fish on land was attributable to poor handling, lack of storage and cooling facilities on fishing vessels and along the lengthy supply chain. Fish disappear after distribution, too, but here the culprits are retailers and consumers, almost exclusively in middle-and high-income countries. In North America, Oceania and Europe, fish waste at consumption far outstrips that of any other region in the world. Pearson thinks retailers in the US partly contribute to the problem by prioritising large, fresh fish to sell at a premium, which quickly spoil. “This is the real tragedy, because it’s moved all the way through the supply chain, and then we’re comfortable with a 10% to 30% loss rate in the grocery store,” he says. When retailers prioritise fresh fish, “the ripple effect is that consumers are more likely to waste that in their homes,” says Love, who published research showing that retailers were responsible for about 16% of wasted seafood in the US, while up to 63% comes down to consumers putting uneaten fish in the bin. Go frozen? Solutions do exist to reduce fish spoilage along the supply chain. Increasing access to cold-chain technologies in low-income countries, along with methods such as solar-powered drying tents, could extend the shelf life of fish. Fishers and processors also need training on better fish handling and storage to limit loss, Peñarubia says. At the consumer end, Pearson and Love argue that we should encourage more people to opt for frozen fish, which could reduce demand for fresh fish in grocery stores, and limit the amount that is lost in retail and people’s homes. Thilsted suggests diversifying our appetites beyond the ubiquitous fish fillet to smaller fish and bivalves, which can be consumed whole to reduce waste. “If our notion of ‘fish’ is a fillet on a pan, then we are already far down the path of loss and waste, because we have reduced the edible part to such a small portion of the whole.” Existing fish byproducts can be captured and turned into new ones. Fish heads, fins, and bones from the fishing industry are already a source of fertiliser and feed; now innovators are finding uses for everything from fish skin for burn treatments, and crustacean waste to make biodegradable packaging. “The idea of full utilisation is something that needs to be pervasive across all food supply chains” says Pearson, who cautions, however, that we shouldn’t overstate these solutions. Unless fish byproducts replace a share of fish demand, they are simply making use of waste – not reducing it at source. Ultimately, prevention is the best solution, starting at sea, where this problem begins, Pearson says. Fishers need to be equipped with more selective gear for fishing, and aided by policies that discourage discards. Sumaila underscores the need for “good subsidies” that can be channelled towards fisheries that help replenish wild stocks: “We need to spend taxpayers’ money in ways that reinforce positive feedback from people to nature, and nature to people,” he says. For generations we’ve believed “the ocean is huge, and we can just take whatever we want,” says Pearson. “Now we’re coming to see the limits of that. And when you have limits, it requires you to become more efficient.”