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Aqua Farming
Why is it not helping our oceans? 


Fish farming 

If you are eating seafood, it is very likely that the fish you had for lunch came from a fish farm. Aquaculture, or fish farming, is booming all over the world because of increasing global demand for seafood, with salmon, tilapia, carp, catfish and shrimp leading the charge. Once celebrated as the solution to overfishing, many countries are in the process of shutting aquaculture down due to severe ecological concerns. See below to find out more about the dangers and threats of fish farming! 

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​1. What is fish farming? 

Fish farming, a form of aquaculture, describes the highly organised and bioengineered process of raising fish in saltwater or freshwater enclosures to be sold for profit. Fish farming is done in natural ponds, rivers, oceans, as well as land-based artificial tanks and lakes. In 2022, the global aquaculture industry was valued at 300 billion USD with an annual growth rate of 5%.  

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2. How does fish farming work?   

Fish farming starts in so-called hatcheries where fish eggs are hatched and raised in large laboratories under controlled conditions until they're big enough to be added to bigger enclosures to grow to size. Some fish farmers catch wild hatchlings and juveniles from natural rivers, lakes, or oceans to grow them into more profitable commodities. Depending on the species, they are being fed pellets, fish meal, live food and supplements including growth hormones, until they have gained enough value and are ready to be harvested. On paper, it’s a perfect system. Stay tuned for the next posts where we explain why aqua culture has not solved overfishing, but instead has created major problems with wastewater, pesticides, diseases and invasive species.  

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3. Does fish farming stop overfishing?  

In short: no. Aquaculture is not stopping conventional fishing and the same species continue to be overfished beyond sustainable levels. Almost 90% of global fish stocks are exploited or overfished! Additionally, fish farmers need krill, anchovies and other fish of lower commercial value to feed larger farmed fish. So – rather than easing the impact on wild populations - we’re killing lots of wild fish to feed the ‘more desirable’ fish we want to eat. 

4. What about diseases and parasites?

Fish farmers will put as many fish in one enclosure as they legally can, like batteries for chicken. Thousands of fish or even more are cramped together in small areas, a perfect breeding ground for diseases and parasites, especially sea lice, and fungal, viral and bacterial diseases. In open-pen fish farms, those diseases spread to native fish populations and destroy the local ecosystem with devastating impacts to other species. Fish diseases can occur naturally in the wild, but their effects often go unnoticed because dead fish quickly become prey. In cramped enclosures, this natural mechanism is absent.  

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5. What about Pesticides?

To prevent the spread of diseases, fish farmers use a wide range of pesticides and antibiotics. Farmers cannot treat individual animals. Instead, large quantities of those chemicals are poured into ocean pens and consequently, the open ocean. Wastewater flushed from land-based facilities also contains pesticides. These chemicals create so called “dead zones” with fatal consequences to native fish species and populations. Those dead zones are a major reason why first world countries are moving their fish farms to the less regulated third world, including Namibia! While fish was once considered a healthy meal choice, farmed fish cannot be considered organic or sustainable.  

6. What happens with the wastewater? 
The unusually high concentration of fish leads to contamination from feces, uneaten food, and dead fish. Open pen farms have no barriers to the open ocean or rivers, and waste products are flushed untreated into the surrounding waters. The same goes for wastewater from land-based fish farms, which often get directed into a nearby ocean or river. This contamination is called eutrophication – we will explain more in our next post!  


7. What is Eutrophication (nutrient pollution)? 

When wastewater from fish farms gets dumped into the ocean or lake, a process called ‘eutrophication' occurs. The water becomes too enriched with nutrients, which leads to excessive plant and algae growth, known as algal blooms. You can see when algae take over because the water turns green or brown or red. Algal blooms are part of nature, and we sometimes see them in Walvis Bay, but they happen a lot more often and more seriously around fish farms. Algal bloom causes low oxygen levels and blocks sunlight, it even clogs fish gills. In short: it kills everything.  

8. How bad is the loss of Habitat? 
Commercial fish farms choose the same prime locations for their operation as marine animals, meaning they both compete for the same breeding and feeding grounds. Huge areas in sensitive and ecologically important habitats need to be cleared to make space. Fish farms change natural currents and take natural habitats away from local flora and fauna. Mangroves need a special mention: shrimp farming has emerged as the primary reason for mangrove destruction and deforestation globally.

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9. What is a Fish Spill? 

Each single enclosure within a commercial fish farm can carry hundreds of thousands of farmed fish. Fish spills, meaning hundreds of thousands of fish escape from their enclosure at once, occur when a net pen ruptures due to corrosion, weather, lack of maintenance or negligence. It is impossible to reverse a fish spill. The escaped fish put local marine life at risk as they are competing for the same limited resources to survive. In case of escaped predators like tuna and salmon, smaller sized fish will be wiped out completely.  

10 . Introduction of non-native species   

The effects of a fish spill are immediate and irreversible. When farmed fish from local species escape and crossbreed with wild fish, they mix their genes and potentially weaken the wild fish by making them less adapted to their environment. Non-native species, such as salmon in Namibia, bring new diseases and parasites that local fish are not resistant to. Non-native fish might prey on local species, which could wipe out entire populations. In short: a fish spill of non-native species changes the balance of the marine ecosystem in an unforeseeable and dramatic way.  

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11. Infrastructure causes entanglement risk to wildlife:

Open-pen fish farms are usually anchored to the ocean floor, held up by buoys and other flotation devices, and connected by walkways, tubing, ropes, or other infrastructure, creating a permanent risk of entanglement, especially when they pose a barrier to natural migrations. Once corrosion, saltwater, bad weather and tides break down the fish farm’s infrastructure, those ropes and nets and other debris turn into ocean rubbish. Some abandoned aquafarms even leave ropes and anchors behind, putting many future generations of marine animals at risk of entanglement.  
The OCN team saw the reality of this risk firsthand when a stressed and panicking whale had to be rescued from a rope that was left behind at an abandoned oyster farm in Walvis Bay! 

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13. Fish Farming and the Economy.  

Many developed nations are implementing strict policies surrounding fish farming or banning the practice altogether due to its devastating environmental impacts. What do investors do now? They move their operations to countries with less rules and enforcement, with the promise of economic development, food security and jobs. We'll explore in the following posts that profits rarely trickle down to the local communities. Instead, they are the ones who are exposed to pollution, ecological destruction and other negative impacts of fish farming.   

12. Predators: a welfare issue     

Fish farms attract predators including birds, marine mammals and fish who will use all their skills to try and break into an enclosure full of their favorite food. The constant sight or even the threat of predators causes farmed fish to remain in a state of constant stress making them more susceptible to diseases. If a predator enters an enclosure, farmed fish cannot protect themselves, they are exposed to injuries and death. To scare away predators, fish farmers use deterrents such as bombs, bean bullets or loud crackers, which cause even more stress among the caged fish. At the same time, predators are exposed to potential entanglement and diseases.  


14. Will Fish Farming bring Jobs?  

Global fish farm operations flock to developing countries with the promise of new jobs. But the advanced technology of fish farming is allowing much of the production system to be automated and only a few, usually less desirable positions are available for locals. As always, most high paying jobs go to foreigners. Instead, traditional fishermen might get pushed out of the market if farmed fish becomes available locally, or if their traditional fishing ground is taken over by commercial fish farms. Even worse – fish farms can have a devastating impact on jobs in tourism when they destroy well-known landscapes that are popular with tourists. Are fish farms a solution for job creation? No, they might even worsen the local unemployment crisis.   


15. Does Fish Farming bring Food Security? 

Big commercial fish farms do not only promise jobs, but they also promise to provide food security. But where in the world do local communities have access to expensive fish such as salmon or tuna? Instead, locally available fish is turned into fish meal to grow salmon in large pens, which then gets exported to upmarket first world retailers. It is not uncommon that several kilos or pounds of low value fish are needed to produce one kg/Lb of luxury fish! Big commercial fish farms want to make money, they do not care about food security when they displace local fishing communities from prime fishing areas and create an ecological disaster.  

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16. Is Land-based Fish Farming better? 

Land-based fish farming avoids some of the issues discussed in our recent social media posts, but it comes with its own challenges. Large commercial fish farms require a lot of water and energy for their feeding, cooling and storing processes. Land-based tanks must be temperature and water-quality regulated 24/7, and wastewater is often directed into the ocean, rivers or lakes.  

Ocean-based and land-based fish farming have one major issue in common with the global meat industry: they rely on manufactured animal feeds like soy or fish meal, which has a major impact on global fish stocks, deforestation and climate change.  

17. Should I eat farmed fish? 

Fish is regarded as a sustainable source of protein and a healthy alternative to meat. But more than half of the globally consumed fish are no longer caught wild, they come from large commercial fish farms where fish are exposed to pesticides and antibiotics. Farmed fish are the equivalent of battery chickens.  

Large commercial fish farms contribute to overfishing and ocean pollution, and they reduce global food security and employment.  The world's appetite for seafood buffets and all-you-can-eat sushi is destroying our oceans. But there is good news too: it is still possible for our oceans to recover. For that, we must change our eating habits. We say: Skip The Fish!  

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19. Future:  

It is projected that by 2030, over 60% of the world’s seafood will be farmed. Global governing agencies have called for better management of fish farms and more research on sustainable practices. But instead of working towards responsible and sustainable fish farming, large commercial fish farms move their operations to less regulated countries, including Namibia. The negative impacts of fish farming are well documented, but usually ignored and moved out of sight. Please give the ocean a voice and reconsider what you put on your plate! 

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18. Would fish farming reduce ocean plastic?    

In short: no. Fish farming relies on fishmeal, which is produced from small, open-ocean fish such as anchovies, herring, sardines, and mackerel. Large amounts of fish must be caught to feed farmed fish and the ghost fishing gear crisis could even worsen! On top of that, ocean-based farms use nets and various plastic materials for their infrastructure, some of them will inevitably end up polluting the oceans.  


20. The future of large Commercial Fish Farming in Namibia:

Namibia has a few major commercial fish farms in the pipeline - three salmon farms in southern Namibia (Lüderitz) and a tilapia fish farm close to Henties Bay. There might be additional, not yet published applications. Currently, Namibia has no regulations in place for fish farming, a paradise for big commercial operations who can do as they please.  

At OCN, we are highly concerned about the impacts on the marine ecology and our local communities. Who will be held responsible if jobs are destroyed and families go hungry?  

Is Namibia able to handle water pollution disasters or major fish spills? Who will monitor wastewater and the impact on local fish stocks?  

We simply cannot allow commercial fish farming under those circumstances.  

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Contact Us:

Namibia: Ocean Conservation Namibia Trust, PO Box 5304, Walvis Bay, Namibia

USA: Ocean Conservation International, 8 The Green, STE A, Dover , DE 19901

©2023 by Ocean Conservation Namibia

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