Is aquaculture the solution?People eat more and more fish. To meet the increasing demand, fish is also farmed in underwater farms. A relief for their free-living counterparts? Unfortunately, no – the growing demand for food poses an additional threat to overfished stocks.
Aquaculture is the fastest growing branch in the global food economy, with growth rates averaging nine percent since 1970. Around 50 million tons of fish and seafood are now produced in freshwater and marine farms. This corresponds to almost half of the edible fish consumed worldwide.
Salmon farm in Norway © Jo Benn / WWF
In order to breed fish from aquaculture, wild fish is additionally caught and fed. These fisheries are often not sustainable. In addition, aquacultures usually cause major environmental damage when chemicals, food residues, fish feces and antibiotics from the open net cages end up in the rivers and oceans. Since the rapidly growing aquaculture industry is taking up a lot of land in the coastal regions of tropical and subtropical countries, valuable habitats such as mangrove forests are being lost as a result of the construction of breeding facilities.
There are several ways to grow fish in aquaculture. Not all methods have harmful effects. Are ecologically questionable: There are also environmentally friendly fish farms. Consumers can be helped by looking at organic labels such as "Naturland" and "Bioland," which are now also available for farmed fish.
Through WWF's initiative, the Aquaculture Stewardship Council (ASC) developed in 2009. The ASC is a broad-based, independent organization that sets the standards. It aims to provide a reliable recommendation for consumers and traders by objectively assessing sustainability aspects of aquaculture and help meet the growing demand for sustainable products.
Impact of aquaculture: factory farming under water
Shoal of fish in mangroves © Tim Laman / naturepl. Fish farms can be located in a variety of places. Have a negative impact on the environment in various ways. This begins with the construction of the facility, continues with its operation, and does not end with its decommissioning.
Even the construction of aquaculture facilities brings with it conflicts – between environmental protection and fish farming, between traditional land use and the new fish farm. This is particularly drastic for shrimp farms – they are located in tropical areas in Africa, South America and Asia. In order to build them, the ecologically valuable. Sadly, threatened mangrove forests are giving way. In the Philippines alone, two-thirds of the mangrove forests have been cleared for the construction of shrimp farms. The Food and Agriculture Organization (FAO) estimates that 3.6 million hectares of mangrove forests have been lost worldwide since 1980. One major reason for this is shrimp farms. A large number of species live in the mangroves. They are the nursery for many species of fish. Their destruction has massive consequences for ecosystems associated with them, coastal protection and fisheries.
Shrimp from a farm in Thailand © Nicolas Axelrod-RUOM / WWF-US
Once the farms are built, they have a massive impact on their surroundings. Most of the world's aquaculture takes place in so-called open systems, which means that the facilities are in direct connection with the natural environment. Such open systems are, for example, net pens that are suspended in the sea and in which salmon or tuna, among other fish, are farmed.
Sinking feed and feces pollute the seafloor beneath the enclosures. Keeping many animals in a small space can cause diseases to spread quickly among them. Therefore, antibiotics. Pesticides used. The soil under the cages is often highly contaminated with the residues from the farms.
Even the ponds typical of shrimp farms accumulate fecal matter, chemicals and medications at the bottom of the facility. If the system is abandoned after a few years, as is often the case with shrimp farms, and dries out, these residues spread into the environment, polluting the soil and potentially leaching into groundwater.
Stress on wild populations
European eel © Erling Svensen / WWF
Farmed fish usually have altered genetic material compared to their wild counterparts. Because these animals are adapted to the conditions of breeding. Selected for their rapid growth. However, specimens repeatedly break out of the farms, mix with their wild relatives and introduce altered genetic material. Diseases from the farms can also be transmitted to wild populations.
Many aquacultures are also established where the species is not native at all. Escaped animals can then disturb the natural balance, for example by competing with native species. The increasingly popular species pangasius. Tilapia, for example, have significantly expanded their distribution area in this way.
In the case of bluefin tuna, the situation is paradoxical: it has not yet been possible to breed tuna in sufficient numbers for the farms. Therefore, for "breeding" in farms, young tuna are caught from the wild and then quickly fattened up ready for fattening.
The same is true for the eel: for their breeding, the small glass eels have to be intercepted off the coast. Since the 1980s, the juvenile population has shrunk to nine percent of its original size. A major reason for this is the glass eel fishery – for direct consumption and export to Asia, but also for aquaculture.
Energy and feed consumption
Salmon in aquaculture in Norway © Erling Svensen / WWF
Some species farmed in aquaculture require regulated temperatures or water supplies. This leads to high energy and water requirements. Besides, the animals must be fed. This often involves the use of fish meal or fish oil, which in turn comes from fishing for wild stocks. Therefore, when it comes to farmed fish, it is better to choose peaceful fish such as carp or species with low fish content in the feed, such as catfish or tilapia.
Environmental label aims to make it easier for consumers to buy farmed fish
Aquaculture is often an ecological disaster. This is why, on the initiative of the WWF, a seal of quality for farmed fish was introduced, based on the model of the Marine Stewardship Council (MSC) for wild fish: the Aquaculture Stewardship Council (ASC). Jointly developed 2.000 Fish farmers, environmentalists, government officials and other stakeholders shared standards for sustainable aquacultures. This includes specific requirements for sustainable farming of the twelve most common aquaculture species.
Sustainable farming means:
The impact of aquaculture on wild fish populations, coastal and marine habitats, water quality and society is minimal. National laws and local regulations must be followed and farming must not harm regional biodiversity. Water and other resources are protected and used responsibly, and farmed fish are kept in a species-appropriate and environmentally sound manner. In addition, farming must be conducted using social standards – such as, among others, workplace safety, non-discrimination and fair working conditions.
So environmentally conscious consumers can look to the ASC label for guidance, or consult the WWF's shopping guide.
How you can help
By becoming a sustaining member, you become part of WWF's wildlife rescue plan! Only sustainable fisheries can protect our oceans. Preserving the fish stock. The ASC standards advocate more environmentally friendly aquaculture. Read more .
The MSC seal for fish
Guiding fish purchases: MSC is still the quickest way to help consumers buy fish. But WWF calls for rapid reforms. Read more .
Fisheries can only survive in the long term if the state of the environment becomes their core ie. Only sustainable fisheries can preserve fish as a resource in the long term. Read more .
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