Yaoyao (not her real name) is a white-collar worker with a Shanghai internet company. She’s also a big salmon fan, eating salmon sushi about three times a month.

“I like salmon more than local seafood. It’s rich in beneficial fats yet doesn’t taste fatty,” she told Dialogue Earth.

When buying salmon, Yaoyao pays most attention to flavour, freshness and food safety. The origin of the fish and its carbon footprint aren’t concerns for her.

She’s not the only fan. Demand for salmon is growing quickly across China, and imports are rising to meet it.

In 2023, China overtook Japan and Korea as the biggest market for Atlantic salmon from Norway. That year, its overall imports of Atlantic salmon were up 46% on the previous year, reaching nearly 93,000 tonnes.

At the same time, a domestic salmon farming industry is starting to take shape, both offshore and on land. Can China learn from the environmental harms salmon farming has caused in other countries, and come up with a greener approach?

Mausam Budhathoki, a post-doctoral researcher at Copenhagen University’s Department of Food Science, thinks China can indeed develop its aquaculture sector in a more sustainable way. This is especially relevant for trout farming, which is relatively new and rapidly expanding in China.

“There’s huge potential for growth in demand,” he said. “If you can use green farming methods from the very beginning, the environmental costs can be significantly reduced.”

Chinese experts, meanwhile, say that water pollution and other issues associated with salmon farming are hard to avoid. It would be better, they say, to focus on native fish of which there are plenty of equally nutritious kinds that can be farmed more sustainably.

The middle class is driving imports

Imports of other types of seafood are also on the rise. Between 2010 and 2022, China’s imports of aquatic animal products have grown by 13% a year, with growth in exports at about 5%, according to a report by the UN Food and Agriculture Organisation (FAO). In 2022, the country became a net importer in terms of value.

The main driver is an expanding middle class in search of better products to consume, while rising labour costs are holding back export competitiveness, finds the report. Gorjan Nikolik, a senior seafood sector analyst with Dutch banking company Rabobank, this year predicted that China would become more reliant on imports, with domestic production unable to keep up with rising demand.

That reliance on imports runs against government efforts to make China more self-sufficient in food production. A 2023 State Council food security report stated that the supply of seafood had to be increased, with the creation of “marine ranches” and an increase in distant-water fishing (beyond Chinese waters). Marine ranching mainly involves releasing juvenile fish into the ocean to grow unassisted for subsequent harvesting. It’s often combined with the construction of artificial reefs, which act as habitats for the young fish and other species.

China’s first attempts at salmon farming

About 70% of salmon sold globally comes from aquaculture farms. With imports costly and demand surging, China has been trying to farm salmon and similar fish locally.

When we talk about salmon, we usually mean Atlantic salmon, but the “salmon” sold on the Chinese market is often rainbow trout, which has a similar appearance, texture and nutritional profile. China has been farming rainbow trout since 1959, and doing so at increasing scale since the 1970s. In 2023, 45,000 tonnes of rainbow trout were produced, both from freshwater and saltwater aquaculture, but the sector is just getting started.

A rainbow trout farmed in Chongqing, south-west China (Image:Huang Wei / IMAGO / Alamy) An Atlantic salmon farmed in the Yellow Sea, Shandong province (Image: Xinhua / Alamy)

Atlantic salmon vs rainbow trout The Atlantic salmon is found in the north of that ocean, from the east coast of Canada across to northern Europe. It is anadromous, which means it spawns in a river, matures in the ocean, and returns to the river to breed. When farmed, it takes three years to mature to the point of sale, spending one year in a freshwater tank and two in marine cages. The rainbow trout, meanwhile, is native to rivers flowing into the north-west Pacific Ocean and the Bering Sea. It was once considered part of the genus Salmo, along with the Atlantic salmon. But in 1989, it was moved to Oncorhynchus, where the Pacific salmon is found. The rainbow trout can spend its whole life in freshwater, or live in saltwater and return to freshwater to breed. It is adaptable, easy to spawn, fast growing and tolerant of a wide range of environments, and as a result is farmed worldwide. Norway and Chile, both of which have mature aquaculture sectors, are the main producers of rainbow trout grown in saltwater. In 2018, China allowed rainbow trout to be labelled as “salmon” for sale, which the media and consumers complained was misleading. Doubts were also raised about transparency and the safety of Chinese rainbow trout.

Freshwater trout aquaculture can take place in mountain lakes, reservoirs or special tanks with flowing water known as raceways. Xinjiang is one of the biggest producers of trout in China, with output of 8,000 tonnes in 2024. Trout are also farmed in Chengdu, which has plenty of cold lakes.

In coastal areas, offshore cages are used, such as the Deep Blue 1 installation and a project off Yantai’s Changdao Island, Shandong province. The Deep Blue 1 has successfully farmed over 600 tonnes of rainbow trout in 2021, and Yantai produced 600 tonnes in 2024.

China also does some farming of salmon. In 2022, Deep Blue 1 harvested a first batch of around 75 tonnes of Atlantic salmon in an experimental aquaculture zone in the colder part of the Yellow Sea.

Local aquaculture could provide low-carbon protein

Producing seafood tends to generate fewer carbon emissions than terrestrial meat, especially beef. Carbon emissions for salmon shipped from Norway to markets in Europe, the US and Asia are in the range of 4.8-28kg per kilogram, with transportation being the largest contributor, according to 2023 work by Norwegian research institute SINTEF.

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In comparison, the greenhouse gas emissions released on a farm to produce 1 kilogram of beef was estimated at 32kg in a study by the UN Food and Agriculture Organization. This high value, which does not include land-use change or transportation, is largely down to methane production.

Mausam Budhathoki says local farming would mean fewer emissions from air freight, and also boost food safety, reduce reliance on imports, and help the agricultural economy. Chinese consumers find no significant difference between rainbow trout farmed in China and Atlantic salmon imported from Norway and Chile, according to a blind taste test Budhathoki conducted with some Chinese scholars in 2024. When informed of the product origins, preferences shifted in favour of the Norwegian and Chilean offerings.

“China has excellent geographical and climatic conditions for trout farming, particularly on the western plateau and in the northern mountains,” said Budhathoki. “The key to developing local aquaculture is more transparency and better quality, to build consumer confidence.”

Avoiding old mistakes

As for salmon farming, other countries, particularly Norway and Chile, have been doing it for much longer than China. Environmental harms have resulted.

Intensive aquaculture means excess fodder and fish excrement are washed out of open-mesh cages, leading to eutrophication of nearby seawater and the spread of bacteria and parasites. Large quantities of antibiotics are often used, leading to microbial resistance, as has happened in Tasmania, Australia.

Faecal pollution visible by a salmon farm in the area of Puerto Montt, Chile (Kevin Schafer / Alamy)

Then there are escapees. A little over 2.1 million salmon have escaped from Norway’s fish farms in the last decade, according to data from the Norwegian fishing authorities, cited by industry news source IntraFish. As these numbers are based on reports from fishing companies themselves, researchers argue the true number could be much higher.

Research has found that escaped salmon breed with wild populations, reducing adaptability and genetic integrity. Parasites and escapees have been the main causes of the decline in wild salmon population – from 8-10 million in the 1970s, to 3-4 million today, shows data from Atlantic Salmon Trust, a UK-based environmental NGO.

Also, farmed salmon are fed fishmeal and fish oil made from wild-caught fish. Such fish is often caught in West Africa where local communities rely on it for their own protein intake, and the facilities for producing it have been linked to pollution incidents. What is more, fishmeal is not very efficient. On average, 0.96kg of wild fish is needed to produce fishmeal enough for 1kg of farmed salmon, according to 2020 data from the Marine Ingredients Organisation, an association of fishmeal manufacturers.

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Researchers have found that those wild fish are often nutritious species suitable for human consumption, and that much of the micronutrients and fatty acids present in them are lost in the conversion to fish feed. A 2022 study demonstrated that “marine-fed farmed salmon is an inefficient way to produce nutritious seafood.” And there are the CO2 emissions mentioned earlier.

Technological advances are allowing fish fodder manufacturers to reduce the need for wild fish by mixing in alternative proteins, such as wheat flour and soybean meal. Though this doesn’t completely solve sustainability issues, globally speaking the number of wild fish needed to produce farmed seafood has fallen considerably between 2000 and 2020.

Mausam Budhathoki highlights that while efforts to develop sustainable feed in collaboration with external partners are underway in China’s salmon and trout farming sector, a sustained focus on environmentally friendly formulations remains crucial.

However, Liu Ruoxi, a hatchery manager for Danish Salmon, a land-based aquaculture company, has traceability concerns. She points out that Chinese fish farms currently aren’t even sure where their juvenile fish come from, so transparency on fodder ingredients seems implausible.

The Chinese Academy of Fishery Sciences has worked with the industry to produce general principles for seafood sustainability and traceability. But there are as yet no mandatory traceability or labelling schemes in operation.

Expert concern over water-pollution risks

Wang Songlin, president and founder of the Qingdao Marine Conservation Society, points out that freshwater aquaculture often draws its water from local water supplies. If aquaculture gets too big or is badly managed, it can compete with local people for that supply, or introduce pollution.

Wang explains that while there is potential for offshore farming of trout and salmon, only a small part of the Yellow Sea, where waters are colder, is suitable. There isn’t yet a system for protecting and monitoring the environment there, with aquaculture expansion moving faster than the associated governance measures. Environmental risks should not be overlooked, said Wang. “The environmental issues arising in northern Europe from open-pen fish farming still haven’t been completely solved. If we don’t take our local conditions into account, but simply copy what they do, we may face the same plight.”

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The industry has been developing ways to raise fish in sealed factory units, preventing pollution from reaching either sources of freshwater or the ocean. An example of this kind of recirculating aquaculture system (RAS) is a project by Nordic Aqua in Ningbo, which can produce up to 5,000 tonnes of fish a year. In 2024, it sold 10 tonnes of Atlantic salmon.

Liu Ruoxi pointed out that RAS is technologically demanding, requiring advanced pumping systems and real-time monitoring to keep risks of pests or disease to a minimum and ensure high survival rates.

It also requires large quantities of water and energy and is more expensive, Liu said. Producers may not be able to recoup that extra expense from price-sensitive consumers. The extra investment required makes RAS only suitable for high-value species. Liu pointed out that while many Chinese firms have acquired RAS set-ups, these are mostly imported from Europe and are harder to run: make one mistake and the fish can very soon die off. The lack of qualified managers means expanding use of RAS will not be easy and the food security benefits are limited.

Farming consumer preferences

Wang Songlin offers a different point of view. The market for salmon in China, he says, was created by the Norwegian government and industry, which has been marketing the fish in China since the 1990s. “It is a manufactured preference, which in turn has prompted the growth of local salmon [and trout] farming.”

This, he thinks, is not ideal. Freshwater species traditionally farmed in China – grass carp, silver carp, European carp – rely on local resources, have low environmental footprints and require less fodder. They are already environmentally and economically sustainable.

He also stressed that while many consumers are fans of salmon for its unsaturated fats, local fish such as the chub mackerel and the Pacific sandlance have the same nutrients. If these were protected and promoted, these could meet the same nutritional needs in a more sustainable manner, he said.