Can aquaculture solve the Mediterranean’s overfishing problem?

Can aquaculture solve the Mediterranean’s overfishing problem?
  • In the Mediterranean, 73% of commercial fish stocks are fished beyond biologically sustainable limits.
  • Part of the strategy to reduce overfishing promoted by the General Fisheries Commission for the Mediterranean, a regional fisheries management organization, is to promote the expansion of aquaculture, which is growing rapidly.
  • However, most fish farms in the region produce carnivorous species, causing concern among experts and NGOs about the risk of worsening the burden on wild marine stocks to produce enough feed.

ST. JULIAN’S, VALLETTA and MOSTA, Malta — Mediterranean countries, under the guidance of the U.N. Food and Agriculture Organization (FAO), are investing in the development of aquaculture as a solution to overfishing. But they farm mostly carnivorous fish, causing concern among experts and NGOs about the risk of worsening the burden on wild marine stocks to produce enough feed for the industry.

In the Mediterranean, 73% of commercial stocks are fished beyond biologically sustainable limits, according to the General Fisheries Commission for the Mediterranean (GFCM), a regional fisheries management organization in the FAO framework that includes 28 countries and the European Union.

Promoting aquaculture was high on the agenda at the GFCM’s MedFish4Ever conference, held Oct. 3-4 in St. Julian’s, Malta. The conference was an intermediate meeting in a 10-year plan to combat overfishing that GFCM member countries signed in 2017.

By introducing new regulations on fishing, the plan has produced some results: overfishing decreased in recent years (partly due to the COVID-19 pandemic), given that in 2016 the GFCM estimated 90% of stocks were fished beyond biologically sustainable limits. Even so, fishing pressure in the Mediterranean “is still double what is considered sustainable,” according to the latest GFCM report from 2022.

In the same period, the Mediterranean marine aquaculture industry also benefited from the strong political will embodied in the plan, increasing by about 30% since 2017, according to Miguel Bernal, the GFCM executive secretary. “This is really good news,” Bernal told Mongabay at the conference. “Now the important thing is to maintain this increase.”

According to Bernal, FAO encourages the growth of aquaculture as a strategy to produce more aquatic foods to meet increasing demand from a growing population. “In the Mediterranean we are also applying this same approach,” he said. “We are trying to develop a sustainable aquaculture that doesn’t impact on the environment but is able to increase the production of aquatic foods.”

Miguel Bernal, the GFCM executive secretary.
Miguel Bernal, the GFCM executive secretary, at the MedFish4Ever conference, held Oct. 3-4 in St. Julian’s, Malta. Image by Francesco De Augustinis for Mongabay.
Fishermen transporting fish crates.
In the Mediterranean, 73% of commercial stocks are fished beyond biologically sustainable limits. Image courtesy of the General Fisheries Commission for the Mediterranean (GFCM).

Fish for feed

Yet a large number of European researchers, NGOs (including Greenpeace and Compassion in World Farming) and local communities from Mediterranean countries such as Spain, Italy and Greece have criticized the rapid growth of marine aquaculture. They point to the pollution it creates in coastal areas and the overfishing it drives to produce feed used to raise carnivorous species, which consume more fish than they provide. In 2020, according to the FAO, 18.1 million metric tons of wild fish, approximately 20% of the total global catch, were destined for non-food uses, mainly fishmeal and fish oil, the bulk of which end up as aquaculture and livestock feed.

In the Mediterranean 53% of marine farms grow sea bream and sea bass, carnivorous fish farmed mainly in Turkey, Greece, Spain and Italy.

“Whenever we are talking about carnivorous fish species (such as salmon, sea bass, sea bream), they still need fish feed and fish oil for their diet in fish farms,” Irmak Ertör, author of a 2018 study about the expansion of marine aquaculture in Turkey, told Mongabay by email. “This means that their fish feed needs to have a significant amount of pelagic fish as its main ingredient,” she said.

Turkey recently became the biggest producer of farmed fish in the region, mainly sea bass and sea bream, having grown from producing 61,000 metric tons in 2002 to 514,000 metric tons in 2022. It gets much of the fishmeal it needs to grow those fish from Morocco, which itself is the main exporter of fishmeal to Europe and the Mediterranean countries. Morocco’s fishmeal production has grown constantly, and in 2021 it exported 150,000 metric tons, mostly to Turkey, Greece and Spain, according to government data collected by the site Western Sahara Resources Watch.

But Morocco’s small-scale fishery is suffering from overfishing, and fishmeal production could make the situation worse, according to Zakia Driouich, secretary-general for maritime fisheries at the Moroccan Ministry of Agriculture. “We have a great migration towards the south of these fishermen who no longer find anything in the Mediterranean,” Driouich told Mongabay during the conference in Malta. “We must prevent aquaculture from contributing to overfishing, for example by fishing small pelagics to feed the fish.”

Attendees to the conference, including Zakia Driouich (left) from Morocco.
Attendees to the conference, including Zakia Driouich (right), secretary-general for maritime fisheries at the Moroccan Ministry of Agriculture. Image by Francesco De Augustinis for Mongabay.

Carnivorous farms

Malta, where the GFCM conference took place, offers another example of aquaculture putting pressure on wild stocks: its high-end bluefin tuna industry, representing 90% of the country’s aquaculture production.

“[It’s] an industry that has developed over the past 20 to 25 years, and has created a name not only for Malta but also for the bluefin tuna,” Charlon Gouder, CEO of Aquaculture Resources Limited, a consultancy that works with four of Malta’s major bluefin-producing companies, told Mongabay at his office in Valletta.

Tuna ranching represents 1% of marine aquaculture production in the Mediterranean, but 6% of the value. Unlike other farmed species, tuna is currently not farmed in a “closed cycle”; rather, the fish are caught across the Mediterranean sea, mostly by Italian and French fishing vessels, and brought to Malta, where they spend four months fattening in cages at sea on a diet of whole fish. In autumn they’re slaughtered to produce fillets, most of which are exported to Japan and South Korea for sushi and sashimi.

According to Tristan Camilleri, an aquaculture specialist with Aquaculture Resource Limited, wild bluefin travel in two size classes: up to 150 kilograms (330 pounds) and up to 210 kg (463 lbs). “After fattening they increase another 40 kg,” or 88 lbs, Camilleri told Mongabay.

Studies estimate that during the fattening period, up to 25 kg (55 lbs) of fish are needed to obtain each kilo (2.2 lbs) of tuna. “Basically tuna is fed baitfish, whole fish, and the quality of the fish we import is equivalent to fish that is good for human consumption,” said Camilleri. He added that most of the fish comes from North European and Mediterranean countries.

Malta’s tuna industry also creates significant waste. “Something around 40% of the tuna is actually not sold,” Simona Paolacci, a scientist at the Malta-based research company AquaBioTech, told Mongabay. Paolacci is working on an EU-funded research project to produce fish feed and ingredients for cosmetics with tuna byproducts, which the industry currently incinerates.

The Maltese government, however, still promotes the growth of aquaculture as a sustainable solution to food security. “I think that investing in more aquaculture in the Mediterranean is important to ensure that we have sufficient fish for the Mediterranean population,” Alicia Bugeja Said, Malta’s parliamentary secretary for fisheries, aquaculture and animal rights, told Mongabay at the GFCM conference. The Maltese representative sidestepped a direct question about the amount of fish used to feed tuna.

Shoals of anchovies and sardines in the Gulf of Naples.
Shoals of anchovies and sardines in the Gulf of Naples, Italy. Image by Franco Tulli / GFCM.
Aquaculture in the Saronic Gulf, Greece. Image by Artur Rydzewski via Flickr (CC BY 2.0).

Technology and demand

According to Bernal, technology is the key to increase aquaculture without putting further pressure on wild stocks. “We are getting there, we are increasing the efficiency of aquaculture, we are increasing the quality of the feeds, we are increasing as well diversifying the species, diversifying the food,” he said.

The reduction of dependence on wild fish is an active area of research globally, and the industry has made some progress. In recent years it exponentially decreased the amount of fishmeal and fish oil used in marine aquaculture by turning to alternative ingredients such as insects, algae, soy, byproducts from livestock and fish farms, and even Antarctic krill. However, some of these raise sustainability concerns of their own. And in any case, fishmeal and fish oil still constitute up to 25% of the feed used to grow sea bream and sea bass.

Moreover, much of the expansion in Mediterranean aquaculture that the FAO and the European Union are driving continues to be in carnivorous species, and the deal signed in Malta in 2017 has no binding rules or specific targets to ensure sustainability standards for the new farms. Among the countries investing in aquaculture projects, Spain, for example, is working on controversial projects to breed tuna in a closed cycle and to farm octopus, another carnivorous species that, according to a 2019 study, requires 3 kg of wild fish to produce 1 kg of seafood.

Asked about the impact of aquaculture on wild stocks, Carlos Fuentevilla, an officer with the FAO’s Fisheries and Aquaculture Division, said that globally the vast majority of aquaculture occurs in Asia and most of it is dedicated to seaweed and vegetarian species such as carps. “In the West it is more difficult to convince people to do that, most people like to eat carnivorous species a bit more,” he said.

In his speech at the conference, Fuentevilla showed estimates predicting that in 2030 the per capita consumption of fish will increase globally, from 20.2 kg (44.5 lbs) in 2020 to 21.4 kg (47.2 lbs) in 2030. “But not in the areas that are required the most,” he said. “We actually suspect that there will be a fold in fish consumption in Africa and an even greater one if we are looking to sub-Saharan Africa.”

Nevertheless, Fuentevilla confirmed that the FAO is working to increase the demand in rich Western countries as well.

“The question is not ‘Is aquaculture sustainable?’ or ‘What’s the impact of aquaculture?,’ but rather ‘What’s the impact in comparison to what?’” Fuentevilla told Mongabay after his speech.

“Of course, the impact of being vegan, for example, is less than eating animal proteins,” he said. “But if you go to eating animal proteins, then, when comparing, of course you will prefer something that comes from aquaculture, no matter if it’s carnivorous fish, to an animal protein from red meat, based on land, because of the environmental impact.”

Banner image: Fishermen at work in the Mediterranean Sea. Image courtesy of the General Fisheries Commission for the Mediterranean (GFCM).

Correction 10/27/23: An earlier version of this story misidentified Zakia Driouich, secretary-general for maritime fisheries at the Moroccan Ministry of Agriculture, in a photo. We have corrected the caption. We regret the error.

Record-breaking seafood production must undergo a ‘blue transformation’: FAO


Aguado-Giménez, F., & García-García, B. (2005). Growth, food intake and feed conversion rates in captive Atlantic bluefin tuna (Thunnus thynnus Linnaeus, 1758) under fattening conditions. Aquaculture Research, 36(6), 610-614. doi:10.1111/j.1365-2109.2005.01210.x

Jacquet, J., Franks, B., & Godfrey-Smith, P. (2019). The octopus mind and the argument against farming it. Animal Sentience, 4(26). doi:10.51291/2377-7478.1504

Ertör, I., & Ortega‐Cerdà, M. (2018). The expansion of intensive marine aquaculture in Turkey: The next‐to‐last commodity frontier? Journal of Agrarian Change, 19(2), 337-360. doi:10.1111/joac.12283

Boyd, C. (2015). Overview of aquaculture feeds. Feed and Feeding Practices in Aquaculture, 3-25. doi:10.1016/b978-0-08-100506-4.00001-5

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