Farmed Fish Are Depleting Oceans of Wild Fish

Written by Dr. Joseph Mercola Fact Checked

fish farm

Story at-a-glance -

  • About 25 percent of wild-caught fish — amounting to about 20 million tons of seafood — are used to make fishmeal that’s fed to farmed fish
  • In West Africa, sardinella is one of the most important fish species for both food security and job creation; it’s also one prized for the production of fishmeal powder
  • Catches of sardinella in West Africa continue to decline, including in Mauritania, where only 172,000 tons were caught in 2017, down 41 percent from the 292,000 tons caught in 2016
  • Prior to the introduction of the fishmeal industry, the sardinella catch was limited naturally by how much the local market would bear; this natural limit has been removed now that fishmeal factories will buy as much fish as the fishing fleets will bring in
  • The fishmeal factories are causing air and water pollution along the coast and threatening the livelihoods of female fish smokers, who are unable to compete with the fishmeal factories, leaving them unable to purchase fresh sardinella to sell to local markets

It's estimated that within the next 10 years, farm-raised fish will make up the majority of fish consumed by humans. There are already 100 species being farmed,1 and while aquaculture, as it's technically known, may sound like a sustainable alternative to catching wild fish, it poses many of the same problems plaguing industrial land-based livestock operations, or concentrated animal feeding operations (CAFOs).

Among these is the need for a concentrated source of food. On land, this often comes in the form of genetically engineered corn and soy, but farmed fish are sustained via a diet of other fish, known as fishmeal. Aquaculture is a $160 billion industry,2 and as one of the fastest-growing sectors in the food production industry, its appetite for fishmeal is immense.

About 25 percent of wild-caught fish — amounting to about 20 million tons of seafood — are used to make fishmeal that's fed to farmed fish,3 and stocks of wild fish may be dwindling as a result.

Sardinella Stocks Dwindling as Demand for Fishmeal Increases

In West Africa, sardinella is one of the most important fish species for both food security and job creation. It's also one prized for the production of fishmeal powder. In Mauritania, a country in Northwest Africa, 770,000 tons of sardinella are caught annually, up from 440,000 tons just a few years ago, according to a 2015 report funded by the European Union.4

Looking to cash in on the growing fishmeal demand, Chinese investors have built factories dedicated to exploiting the seemingly copious amounts of fish in Mauritania, Senegal and Gambia.

Yet, according to Abdou Karim Sall, president of an association of small-scale fishermen in Senegal, who spoke to Reuters, "In four or five years, there won't be any fish stocks left; the factories will close, and the foreigners will leave ... We'll be left here without any fish."5

In a Reuters investigation, it's revealed that aquaculture is increasingly taking sardinella away from the local people who depend on it for their survival. Reuters reported:6

"Sardinella migrate across a 1,000-mile zone shared by Mauritania, Senegal and Gambia. Officials from each country insist that they want to manage their fish sustainably and develop the kind of processing, freezing and export industries that could create thousands of jobs.

But with no effective regional management system yet in place, this goal may not be compatible with installing ever-more grinding machines for the benefit of fish farms producing food for Asia, Europe and North America."

Fishmeal Factories Encourage Local Fish Fleets to Exploit Fish Stocks

According to the Coalition for Fair Fisheries Arrangements (CFFA), which promotes the livelihoods and food security of costal fishing communities, catches of sardinella in West Africa continue to decline, including in Mauritania, where only 172,000 tons were caught in 2017, down 41 percent from the 292,000 tons caught in 2016.7

Prior to the introduction of the fishmeal industry, the sardinella catch was limited naturally by how much the local market would bear. This natural limit has been removed now that fishmeal factories will buy as much fish as the fishing fleets will bring in. Marine scientist Patrice Brehmer told Reuters, "We could face a catastrophic situation."8 CFFA agrees, noting:9

"Whereas the effort by artisanal fleets in earlier years was restricted by the demand from the human consumption market, this restriction no longer exists at the moment. The fishmeal plants can absorb large quantities of fish, which stimulates artisanal fishermen to increase their effort.

Mauritanian fishmeal plants have even brought in a completely new fleet of efficient Turkish purse seiners to supply them with fish.

Senegalese fishermen from Casamance are now landing catches at fishmeal plants in Gambia. Sometimes these landings are so big that even the fishmeal plants cannot absorb them. As a result, considerable quantities of sardinella have to be dumped at sea or on the land."

Fishmeal Factories Threaten Job Security, Cause Pollution

Job security is also being threatened. Senegal's national dish, known as thiéboudiène, features smoked sardinella, which are carefully dried and smoked by thousands of women working in the sardinella smoking industry.

Whereas the demand for smoked sardinella was once high from local markets, now this activity is threatened because fishmeal factories are buying up all the sardinella, paying twice as much as the women fish smokers can, "leaving them with nothing but time on their hands," Reuters reported.10

The women can no longer afford to purchase fresh sardinella, leaving them out of jobs and the local residents without smoked sardinella to enjoy. Many fishermen are also wondering if they'll soon be forced to find a new line of work.

Gaoussou Gueye, a veteran fishmonger, told news outlet DW, "When the ships go out to sea together, there are not enough fish and they return without any catch. People are thinking there are no more fish left ... If we still had enough fish in Senegal, we would not to have to look for licenses in other countries to fish."11

What's more, the fishmeal factories are causing air and water pollution along the coast. Physicians in the area have even reported an increase of illnesses related to the pollution. Moctar Ame, an ear, nose and throat specialist in Nouadhibou, a city with more than 20 fishmeal factories, told DW that 20 percent of his patients have diseases caused by the factories' pollution:12

"There are many diseases that are directly related to the pollution of these factories. They release toxic air particles. When these particles enter the body, they cause allergies, chronic bronchitis and skin rashes. We cough a lot and have infected throats because of these particles."

Ninety Percent of Fish Used for Fishmeal Could Be Eaten by Humans Instead

The notion of fish farming becomes far less sustainable when you consider that growing fish is using up valuable supplies of fish that could be eaten directly by humans.

A study published in the journal Fish and Fisheries even revealed that most fish destined for fishmeal production are food-grade or prime food-grade fish that could be used to feed people.13 Study author Tim Cashion, research assistant at Sea Around Us, told NPR:14

"I was expecting there to be more truth to the argument that most of these fish don't have a place for human consumption, that there's generally not a market or a possibility of a market for these fish, but that's not what we found ...

In a world with many food insecure populations and people that could substantially benefit from having more fish in their diet ... that we're using 20 million tons of fish to feed aquaculture and livestock production? I think people should care about that."

Many farmed fish species, including tilapia and carp, are fed fishmeal. Further, about 30 percent of fishmeal production is used to feed CAFO animals including pigs and chickens. The types of fish used for fishmeal are also expanding to include not only sardinella and similar fish like anchovies, but also pompanos, drums and even some crustaceans.

It's a concerning finding, considering human exploitation, including overfishing, is the major cause of declining marine species, with some declining in numbers by 74 percent between 1970 and 2010.15

Farmed Fish Spread Diseases to Wild Fish

Aside from threatening wild fish stocks for the production of fishmeal, farmed fish also threaten wild fish by spreading disease, including sea lice and piscine reovirus (PRV). Sea lice are tiny parasitic crustaceans that feed on salmon skin and mucous. Just one or two sea lice can kill a juvenile salmon, with the lice literally eating the salmon alive, and adults may also be harmed if infestations occur.

As noted by Watershed Watch Salmon Society, "Even if average sea lice levels are kept 'low' on a farm, even very low numbers of lice per farmed salmon can add up to billions of sea lice eggs being released into surrounding waters."16

PRV, meanwhile, causes Heart and Skeletal Muscle Inflammation (HSMI) disease, which can be deadly to salmon. One study of salmon in British Columbia, Canada, revealed the proportion of PRV infection in wild fish was related to exposure to salmon farms.17

PRV was detected in 95 percent of farmed Atlantic salmon and up to 45 percent of wild salmon from regions highly exposed to salmon farms. In contrast, only 5 percent of wild salmon living in regions farthest from salmon farms were infected.

Not Good for Oceans, Not Good for You

Nutritionally speaking, farmed fish are also a far inferior choice to the wild variety. For starters, their pens are often placed near shore, which means they're close to land-based sources of pollutant runoff. In addition, their diet of ground-up fishmeal may lead to concentrated levels of toxins like PCBs.

In a global assessment of farmed salmon published in the journal Science, PCB concentrations in farmed salmon were found to be eight times higher than in wild salmon.18 What makes fishmeal so toxic? In some cases, the fish used to make the feed comes from polluted waters.

Some of the toxicity also stems from the manufacturing process of the pellets. The fatty fish are first cooked, resulting in two separate products: protein meal and oil. While the oil has high levels of dioxins and PCBs, the protein powder also adds to the toxicity of the end product. To this protein powder, an "antioxidant" called ethoxyquin is added.

According to the documentary "Fillet-Oh-Fish," this is one of the best kept secrets of the fish food industry — and one of the most toxic. Ethoxyquin was developed as a pesticide by Monsanto in the 1950s. Its use is strictly regulated on fruits, vegetables and in meat, but not in fish, because it was never intended for such use.

The effects of this chemical on human health have never been established. The one and only study ever done on ethoxyquin and human health was a thesis by Victoria Bohne, a former researcher in Norway who made a number of disturbing discoveries, including the fact that ethoxyquin can cross the blood-brain barrier and may have carcinogenic effects.

Are There Any Healthy Seafood Options?

Because much seafood is polluted, I only recommend eating safer seafood choices such as wild-caught Alaskan salmon, sardines, anchovies, mackerel and herring. All of these are at low risk of contamination, yet are high in healthy omega-3 fats. You'll want to opt for sustainably harvested wild-caught fish as well.

One of the best options toward this end is to look for the Marine Stewardship Council (MSC) logo, which features the letters MSC and a blue check mark in the shape of a fish. The MSC logo ensures the seafood came from a responsible fishery that uses sustainable fishing practices and meets the following standards:19

  • Fish stocks are sustainable — there are enough fish left in the sea to reproduce.
  • Environmental impacts are minimized — fishing operations must be carefully managed to maintain the structure, productivity, function and diversity of the marine ecosystem.
  • Effective management — the fishery must comply with relevant laws and have a management system that allows it to respond quickly to changes in the status quo.