A 2021 Chinese government initiative to stop aquaculture feed being made from only young or low-value fish and to instead start producing “compound feed” – mixed with ingredients harvested from the land – is opening up a greener future for the sector.
According to the Ministry of Agriculture, in a series of trials last year, the sole use of low-value “feed-grade” fish as aquaculture feed was reduced by 77%, and by as much as 94% in farming of largemouth bass. Experts say the switch to compound feed could see overall use of feed-grade fish slashed by half for farming of certain species.
What is compound feed?
Compound feed normally contains a mixture of animal- and plant-based ingredients, and added nutrients such as vitamins. For aquaculture feeds containing fishmeal and fish oil, common additives include soy proteins, wheat gluten and corn gluten meal.
Feed-grade fish are those in a catch that are small, low in commercial value, or unsuitable for human consumption. They are sent to be processed into fishmeal and fish oil, or fed directly to farmed fish. But a significant proportion of feed-grade fish consists of juveniles of commercially important species. Once caught they can no longer grow into adult fish and breed, or be caught and sold on the market. Their removal damages ocean food chains and ecosystem stability.
The last decade and more has seen increased calls for China to tackle the use of feed-grade fish in aquaculture, but the current round of trials is the first organised by the Ministry of Agriculture. It focuses on species such as the yellow croaker, Japanese sea bass and largemouth bass, which tend to be fed more feed-grade fish. While those species don’t account for much of China’s fed aquaculture output, they do require much more protein than others to put on the same amount of weight. Compound feed cuts down on the use of fish by substituting vegetable alternatives, and is cheaper.
In the long term, sustained reductions in the use of fishmeal and fish oil in feed will be necessary to protect wild fisheries.
Aquaculture driving feed-grade fish catch
Fishers never used to set out to catch feed-grade fish; it was bycatch, with no economic value. Then in the 1980s, global aquaculture took off. “There was a lot of need for fishmeal and oil,” Rashid Sumalia, a fisheries researcher at the University of British Columbia, told China Dialogue. People started going out “purposely to catch them at distance, because there was a market”, he added.
According to the Food and Agriculture Organization’s (FAO’s) 2020 global fisheries and aquaculture report, the use of fish for reduction to fishmeal and fish oil peaked in 1994 at 30 million tonnes, and stood at 18 million tonnes by 2018. Another 4 million tonnes were used elsewhere, including directly in feed for aquaculture, livestock and fur animals.
It wasn’t until the mid and late 1990s that aquaculture took off in China. The FAO’s 1998 fisheries and aquaculture report describes how rare it was for fish catches in Asia to go unused or be used as aquaculture feed. But in Asia, particularly in China and Vietnam, aquaculture has expanded rapidly and the region now accounts for almost 90% of global output. In China, output tripled between 1998 and 2020, to represent 60% of the global total.
Although many of the species farmed in China need little or no feed, fed fish and crustacean aquaculture accounts for half of output and requires millions of tonnes of feed-grade fish from Chinese waters alone. China does not currently have statistics on its feed-grade fish catch or use in fed aquaculture. One study calculated that in 2016 4.6 million tonnes of feed-grade fish were caught, 35% of the total recorded catch in China’s waters, and most was used directly as feed.
“The state is certainly aware of the problem,” said Fang Qing, China general manager for the Aquaculture Stewardship Council, adding that the difficulty in banning some harmful types of fishing gear in China is due to the ongoing market for the feed-grade fish it brings in. Since 2018, China has put minimum size limits in place for 15 commercial fish species, and ruled that feed-grade fish catch would drop to below 20% by 2020. There is no data available indicating whether this target was met.
This it isn’t just a Chinese problem. According to a 2017 study by the University of British Columbia, many countries, including the US and Norway, use feed-grade fish directly as feed. But the practice increased significantly in Asia between the 1990s and 2010, with feed-grade fish coming to account for a high percentage of landed catches.
Replacing feed-grade fish
In early 2019, the Ministry of Agriculture announced it would work to make Chinese aquaculture more environmentally friendly, and proposed the use of compound feed instead of purely fish-based feed. In April 2021, several provinces started trials of compound feed as part of more concrete action plans.
Compound feed for aquaculture is usually a mix of fishmeal, fish oil, wheat flour, soybean meal, vegetable oil and other land-grown ingredients. The amount of fishmeal and fish oil needed depends on the type of fish to be fed, and its stage of growth. According to Fang Qing, carnivorous fish such as the yellow croaker need huge quantities of meat protein at certain stages in their growth, and the relationship between particular nutrients and the growth and physiology of the fish can be complex. Hence, producing appropriate compound feed involves a lot of research and development.
To quantify how efficiently a species is farmed, the aquaculture industry uses a ratio called Fish in:Fish out (FIFO). The closer the FIFO is to 1, the more fish meat is produced per unit of input; a score of 1 means an extra kilogram of fish used as feed results in an extra kilogram of fish to harvest.
A study published in 2020 shows a FIFO of almost 1 for salmon and trout, thanks to the use of compound feeds which require less fishmeal and fish oil. If only fish were used to feed those species, the FIFO figure would be similar to that of the yellow croaker – over 6, according to an upcoming paper co-authored by Zhang Wenbo, an assistant professor in the College of Fisheries and Life Science at Shanghai Ocean University. His research into conventional yellow croaker aquaculture in China found that the direct use of feed-grade fish is still the best option for the yellow croaker farmers. But Fang Qing told China Dialogue that a lot of feed-grade fish fed to yellow croaker goes uneaten, and ends up sinking to the seabed or rotting, causing pollution and increasing the risk of disease.
A more complete solution would be to develop entirely vegetarian feeds
More compound feed use would help reduce FIFO numbers in two ways: by cutting use of feed-grade fish, and by increasing conversion ratios – that is, generating more fish growth per unit of feed.
Zhejiang is taking the lead in both those areas. Since 2016, the province has been shutting fishmeal factories during the closed season and restricting the percentage of feed-grade fish in the overall catch. This, combined with the use of compound feed, saw Zhejiang cut the use of feed-grade fish by 835,000 tonnes across 710,000 mu (474 square kilometres) of aquaculture farms during the 13th FYP period (2016-2020). “Previously, feed-grade fish were the primary feed for largemouth bass in Zhejiang. These last two years that’s almost all been replaced with compound feed.” The FIFO ratio for farmed largemouth bass in Zhejiang could come down to 1.5, half the national average for this species, according to 2016 calculations Zhang Wenbo contributed to.
But cutting back on feed-grade fish use in China won’t be easy. Fishers catch a wide range of fish with a wide range of gear. At the local level there is a lack of fisher associations that can impose rules on the sector, making management tricky. Zhejiang’s success can be ascribed to strong local regulations. “There are no successful [international] examples that China can apply,” said Fang Qing. Alongside legislation to bolster oversight of the feed-grade fish catch, he also suggests developing feeds which will be more palatable to fish, and labelling products according to their use of feed-grade fish or compound feed, so consumers can make an informed choice.
Increasing the efficiency of fish inputs
The use of compound feed isn’t the end of the story. At least for now, fishmeal and fish oil are essential ingredients in those feeds. And while the global supply of fishmeal and fish oil has fallen from its peak in 2000 to a fairly stable level, the demand for aquaculture feeds has been increasing. That requires the development of feeds containing less meal and oil.
Plans announced by Norway to boost salmon farming have led to concerns about the supply of fishmeal and fish oil as well as vegetable ingredients. The country has started researching the use of mesopelagic fish (which inhabit the middle depths of the ocean), algae and farmed insects to meet that need and make feed more efficient. A more complete solution would be to develop entirely vegetarian feeds, with no fishmeal at all. However, as things stand that would only be suitable for a few species.
“Fishmeal is the most expensive of the ingredients found in bulk feeds. Reducing the amount in those feeds is the best way to make them cheaper,” Zhang Wenbo points out. A tonne of fishmeal costs around 10,000 yuan (US$1,500), compared to 1,000–4,000 yuan for bran or soybean meal, he added. “Feed conversion ratios are also affected by the type of aquaculture, the make-up of the feed, and genetic selection – the breeding of strains more suited to compound feeds,” he said. This is more difficult in China, with its wide range of farmed species, than in Norway, where salmon dominates. But progress is still being made, and associated targets have been set in the 14th Five Year Plan (2021–25).
Increasing the efficiency of fishmeal and fish oil use in China will also ease global pressures on the supply and help protect juvenile fish. China is the world’s biggest consumer of fishmeal, with the largest part being used in aquaculture, and the second largest being fed to pigs. But the country only produces 400,000–700,000 tonnes of fishmeal a year – not even close to meeting domestic demand. Fishmeal imports have held steady since 2017, at about 1.4 million tonnes, but jumped to 1.82 million tonnes in 2021, with experts ascribing the change to the recovery in pig farming. The extra fishmeal came from the Americas and elsewhere in Asia.
Zhang Wenbo explains that China’s fishmeal and fish oil imports come from forage fish, caught specifically to be turned into fishmeal, and Peru is the main supplier. Relatively little of China’s fishmeal is made from feed-grade fish. “Imports of by-product processed fishmeal from Vietnam and Thailand have been increasing in recent years,” he said.
Minimising the feed-grade fish catch
Cutting back on the use of feed-grade fish is good for the sustainable development of both wild fishing and aquaculture. It will also help protect already vulnerable ocean ecosystems. In 1959, fishing vessels in China’s Bohai Sea caught 420 kg of fish per net for every hour they worked. By 1993, that had fallen to 30 kg, and only 8 kg between 1998 and 2011. The above-mentioned research into China’s feed-grade fish catch found that a long-term stable total catch has masked trends including falling biomass and changes in end use.
The losses to biodiversity and ecological services cannot be measured in financial terms, and the fishing industry needs more than simply output. Wang Songlin, president and founder of the Qingdao Marine Conservation Society, believes the industry needs to work towards a balance of ecological, economic and social benefits. He told China Dialogue that even if total catch may still be the same by volume, the underlying destruction to the integrity of ecosystems and the environment should not be ignored.
Management of the sector in China has acquired a new ecological focus. Alongside the use of compound feeds, some provinces are providing fishery stewardship subsidies for the protection of rare and endangered species and for keeping down feed-grade fish catch volumes.
Protecting juvenile fish isn’t just a matter for China – it’s crucial for ocean ecosystems around the world. Rashid Sumalia said: “If you look at the economies and the ecology at the higher level, you don’t want to [catch feed-grade fish] because the losses are too high” to be sustainable. Sumalia acknowledges that many people rely on that fishing for their livelihoods but says: “We need to take it down as far as we can.”