A 2021 Chinese government initiative to stop aquaculture feed being made only from young or low-value fish and instead starting to produce “compound feed” – mixed with land-harvested ingredients – opens up a greener future for the sector.
According to The Minister of Agriculture, in a series of trials last year, the exclusive use of low-value “food grade” fish as feed for aquaculture was reduced by 77%, and up to 94% in the largemouth bass farming. Experts say switching to compound feeds could lead to a halving of the overall use of food-grade fish for farming certain species.
Forage quality fish are those of a catch that are small, of low commercial value or unfit for human consumption. They are sent to be processed into fishmeal and fish oil, or directly fed to farmed fish. But one high proportion of forage quality fish consists of juveniles of commercially important species. Once caught, they can no longer grow into adult fish and reproduce, nor can they be caught and sold in the market. Their elimination harms the food chains of the oceans and the stability of ecosystems.
Over the past decade-plus there have been increasing calls for China to tackle the use of food-grade fish in aquaculture, but the ongoing series of trials is the first organized by the Ministry of Agriculture. It focuses on species such as yellow croaker, Japanese bass, and largemouth bass, which tend to be fed more food-grade fish. Although these species do not make up a large portion of China’s fed aquaculture production, they require significantly more protein than others to gain the same weight. Compound feeds reduce the use of fish by replacing them with vegetable alternatives and are cheaper.
In the long term, sustained reductions in the use of fishmeal and fish oil in animal feed will be needed to protect wild fish stocks.
Food grade fish replacement
In early 2019, the Ministry of Agriculture announcement he would work to make Chinese aquaculture more environmentally friendly and proposed the use of compound feeds instead of purely fish-based feeds. In April 2021, several provinces began trials of blended feeds as part of more concrete action plans.
Compound feeds for aquaculture are usually a mixture of fishmeal, fish oil, wheat meal, soybean meal, vegetable oil and other land-grown ingredients. The amount of fishmeal and fish oil needed depends on the type of fish being fed and its growth stage. According to Fang Qing, carnivorous fish such as yellow croaker require huge amounts of meat protein at certain stages of their growth, and the relationship between certain nutrients and fish growth and physiology can be complex. Therefore, the production of suitable compound feed involves a lot of research and development.
To quantify the breeding efficiency of a species, 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 that an extra kilogram of fish used as food results in an extra kilogram of fish to be harvested.
A study published in 2020 shows a FIFO of almost 1 for salmon and trout, thanks to the use of compound feeds that require less fishmeal and fish oil. If only fish were used to feed these species, the FIFO figure would be similar to that of the yellow croaker – more than six, according to a forthcoming paper co-authored by Zhang Wenbo, assistant professor in the College of Fisheries and Life Science at Ocean University. from Shanghai. His research on conventional yellow croaker aquaculture in China revealed that direct use of food-grade fish is still the best option for yellow croaker farmers. But Fang Qing told China Dialogue that many food-grade fish fed with yellow croaker are not eaten and end up sinking to the seabed or rotting, causing pollution and increasing the risk of disease.
Greater use of compound feed would help reduce FIFO numbers in two ways: by reducing the use of food-grade fish and by increasing conversion rates, i.e. generating more growth of fish per unit of food.
Zhejiang leads in both areas. Since 2016, the province is closure of fishmeal factories during the closed season and limiting the percentage of forage quality fish in the overall catch. This, combined with the use of compound feed, enabled Zhejiang to reduce the use of food-grade fish by 835,000 tons on 710,000 mu (474 square kilometers) of aquaculture farms during the 13th FYP period (2016-2020).
“Previously, food-grade fish was the main food for largemouth bass in Zhejiang. In the past two years, almost all of it has been replaced by compound feed.” The FIFO ratio for largemouth bass breeding in Zhejiang could drop to 1.5, half the national average for this species, according to 2016 calculations contributed by Zhang Wenbo.
But reducing the use of feed-grade fish in China will not be easy. Anglers catch a wide range of fish with a wide range of gear. At the local level, there is a lack of fishermen’s associations that can impose rules on the sector, which makes management tricky. Zhejiang’s success can be attributed to strict local regulations. “There is no success [international] examples that China can apply,” Fang Qing said. Along with legislation to strengthen monitoring of food-grade fish catches, it also suggests developing foods that will be more palatable to fish and labeling products based on whether they use food-grade fish or compound foods, so that consumers can make an informed choice.
Minimize the catch of food-grade fish
Reducing the use of forage quality fish is good for the sustainable development of wild fisheries and aquaculture. It will also help protect already vulnerable ocean ecosystems. Losses of biodiversity and ecological services cannot be measured in financial terms, and the fishing industry needs more than just production.
The management of the fisheries and aquaculture sectors in China has acquired a new ecological orientation. Along with the use of compound feed, some provinces provide fisheries stewardship grants for the protection of rare and endangered species and to limit the volumes of catches of food-grade fish.
Protecting juvenile fish isn’t just China’s business, it’s crucial for ocean ecosystems around the world. Rashid Sumalia, a fisheries researcher at the University of British Columbia, said: “If you look at economies and ecology at a 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 depend on this fishery for their livelihoods, but says, “We need to reduce it as much as possible.