Responsible aquaculture can have a good impact on the environment. On the other hand, irresponsible fish farming can have negative effects on the environment in different places and in different ways. This begins with the construction of the plant, continues during operation, and does not end when it is shut down.
Negative effects of fish farming
Even the establishment of aquaculture facilities brings conflicts – between environmental protection and fish farming, between traditional land use and the new fish farm. This is particularly drastic with shrimp farms – they are located in tropical areas in Africa, South America, and Asia. For their establishment, the ecologically valuable and unfortunately threatened mangrove forests have to give way in many places. In the Philippines alone, two thirds of the mangrove forests have been cleared for the establishment of shrimp farms. The World Food Organization (FAO) estimates that 3.6 million hectares of mangrove forests have been lost worldwide since 1980. Shrimp farms are a major reason for this.
A wide variety of species live in the mangroves and they are the nursery for many species of fish. Their destruction has massive consequences for the ecosystems connected to them, for coastal protection and fisheries. People who love fishing might have difficulty in finding the right spot to fish using their fly fishing waders.
Pollution caused by fish farming
Once the farms are established, they have a massive impact on their surroundings. Most of the world’s aquacultures take place in so-called open systems, which means that the systems are in direct contact with the natural environment. Such open systems are, for example, net cages that are hung in the sea and in which, among other things, salmon or tuna are bred.
Sinking food and feces pollute the seabed beneath the enclosures. By keeping many animals in a confined space, diseases can spread quickly among them. Therefore, antibiotics and pesticides are used. The soil under the cages is often heavily polluted with the residues from the breeding.
Even in the pond systems typical for shrimp farms, feces, chemicals, and medication will remain at the bottom of the system.