Fish is brain food. This is a lesson we learned from our mothers and grandmothers. They were right—the Omega-3 fatty acids in fish are good for our health. Omega-3 is an essential fat, but our bodies cannot make it, so it must come from the food we eat, and fish is the best source. Fish, like people, cannot make Omega-3, so they too get it from their food.

China has the largest aquacultural production in the world, growing fish and other seafood in ponds and tanks. The growth in China’s aquaculture is filling in the gap between high demand for fish and the leveling off of catches of wild fish. However, in China, the United States, and elsewhere, feeding all the fish grown in aquaculture remains a challenge. Fishing fleets around the world harvest small, forage fish (also called “bait fish”) from the ocean to make fishmeal and fish oil that is high in Omega-3 that goes into fish food. Annually, about 19 million tons of wild fish are processed globally into fishmeal and fish oil. Aquaculture currently uses 75 percent of global fish oil supplies. 

From whales to sea birds, small fish are an important food source and the foundation of the marine ecosystem. Thus, feeding wild small ocean fish to farmed fish does not solve the problem of not enough fish in the sea. The current rate of harvesting ocean forage fish to feed farmed fish, like salmon, trout, and bass, is not sustainable, and may lead to the collapse of the forage fishery.

At the base of the food chain, algal plants make small amounts of Omega-3. When little fish and crustaceans eat these plants, and then are consumed by bigger fish, Omega-3 concentrations increase. This makes fish high on the food chain, like salmon, a great concentrated source of Omega-3. Photo credit: Shutterstock/ EreborMountain

Extending the Ocean’s Wild Forage Fish Tipping Point 

Small forage fish like sardines, anchovies, and herring are natural fish food, supplying all of the necessary nutrients for valuable and delicious, carnivorous aquaculture species like salmon. However, balancing the growing demand for seafood within the sustainable ecological limits of forage fish production is a big challenge. Researchers now estimate the demand for forage fish will exceed the ocean’s supply, hitting the tipping point by 2037. Policy intervention is needed to halt the overharvesting of oceans for fish feed and to incentivize two existing sustainable options. 

First, aquaculture farmers in China and beyond need to stop feeding fishmeal and oils to animals that do not need it. Non-carnivorous and freshwater fish, like carp, do not need Omega-3 in their diet. Also, the common practice of adding fishmeal to pig and poultry feed is unnecessary. Regulations that require changing feed formulations to exclude fishmeal would extend the tipping point for the forage fishery to 2050.

Second, fishmeal and oil made from fish trimmings and byproducts are underutilized sources of protein and Omega-3 in aquaculture. Fishmeal from trimmings now contributes one-third of global production. Ten countries, including the United States, recycle fish byproducts. If China—the world’s biggest fish processor—joins the trend, the tipping point can move back another six years.

Alternative Fish Food

Putting a worm on a hook for the first time to catch a fish is a fond childhood memory for many. Worms and insects are fish food and are raised worldwide to supply aquaculture. A female entrepreneur in Kenya founded InsectiPro to grow soldier fly larvae that are processed into high-protein livestock and fish feed. She grows the larvae on food waste diverted from the landfill.

Soybeans and canola are also a good source of oil and protein in animal feed, and are fed to pigs, cattle, and poultry, but are not an ideal fish food. Some of the plant protein is indigestible by fish, which increases the volume of fish waste and pollution. Neither insect nor grain meal contain Omega-3, so they do not completely fill the fish food gap.

Algae is emerging as the natural source of Omega-3. NASA developed the technology to grow microalgae to produce both oxygen and Omega-3 for astronauts in space. Using this technology, the company Veramaris built small plants in the United States and European Union to grow algae in tanks on sugar from corn. The Omega-3 rich oil is extracted, and the algal solids become cattle feed. A large algae oil production plant is now under construction in Nebraska to supply 15 percent of the global aquaculture fish oil demand. Researchers continue to explore more ways to produce Omega-3, using the nutrients from cattle and swine waste to grow algae.

Lagging Regulations of Forage Fish for Fishmeal

Chinese aquaculture is shifting to higher-value, premium species that need Omega-3 in their diet. The Chinese government and corporations are investing and working to professionalize aquaculture as a poverty alleviation strategy. Farmers are moving away from low-value carp to grow bass. This demand for carnivorous fish that are higher in the food chain and need to eat fishmeal made from forage fish is driving the unsustainable increase in importation of fishmeal for aquaculture, says University of Missouri aquaculture specialist, Dr. David Brune.

Environmental and market pressures to limit the use of forage fish for fishmeal are mounting, however. In the waters of China’s exclusive economic zone (200 nautical mile from the coast), 35 percent of the catch is forage fish, and supplies are dropping rapidly. Unfortunately, fishing licenses, catch moratoriums, and minimum net mesh size requirements are still ineffective at controlling forage fish over-exploitation. Fishmeal prices have tripled in the last decade, and fishmeal factories are below full capacity, increasing competition for a short supply. 

Chinese fishing fleets are catching wild fish food around the world. The 2006 fisheries fuel subsidy is blamed for keeping 90 percent of the Chinese distant fishing fleet viable and a motivation for overfishing. The fuel subsidies are now being phased out. Photo Credit: Shutterstock / Igor Grochev

The hunt for fishmeal for aquaculture has even sparked conflicts overseas. For example, in March 2021, a Chinese-owned fishmeal factory was torched by Gambian youths in West Africa. Local residents linked the plant to extensive environmental and economic damage of coastal fisheries, threatening local fishing communities.

In 2007, the U.S. National Oceanic and Atmospheric Administration (NOAA) with the U.S. Department of Agriculture (USDA) launched an aquaculture alternative feed initiative to reduce the amount of fishmeal and oil needed. The research has already generated information on probiotics, dietary requirements and alternative feed. The U.S. Senate is considering the Forage Fish Conservation Act, a bipartisan effort to conserve, monitor, and manage fish stocks. Currently, only anchovies have catch limits and Oceana has sued NOAA over inadequate management.

Managing forage fish harvesting in U.S. and Chinese coastal waters is just tiptoeing around a serious ecological issue. Since countries only have direct control of their own waters, international policies and agreements are needed to manage sustainable fisheries on distant coasts where lack of training, knowledge, and enforcement threatens fish stocks. Policies need to set limits on the harvest of forage fish, protect breeding areas, and prioritize the uses of forage fish. The 2016 U.N. Agreement on Port State Measures to Prevent, Deter, and Eliminate Illegal, Unreported and Unregulated Fishing is one step towards long-term conservation and sustainability of marine resources. So far, the United States and 68 other countries have signed the agreement, but not China.