Aquaculture is the fastest-growing area of food production in the world. Often suggested as the future of the fish industry, in its current state, it is not a solution to overfishing.
While in certain places some forms of aquaculture can provide an important food source, they must be developed responsibly. The rapid growth of intensive aquaculture for species with high commercial value intended for export—such as salmon and shrimp—has already caused dreadful environmental damage and the displacement of many local farmers and fishers whose livelihoods have been destroyed.
Some of the main problems with aquaculture:
Intensive fish farms release enormous quantities of organic waste (fecal material) and contaminated water into the environment around the farm sites. Every day, all the salmon farms in Scotland put together produce as much excrement as the 600,000 inhabitants of Edinburgh. As a result, the surrounding waters see accelerated, chaotic algae growth, which can prove deadly for certain marine animals and indirectly constitute a danger to humans who end up eating contaminated shellfish. When an ecosystem has become too compromised, the farm is simply moved elsewhere.
Often coastal ecosystems are completely destroyed in order to make room for intensive aquaculture. This is the case with the artificial ponds created to farm tropical shrimp. Mangroves are chopped down, leading to the disappearance of all the species that used to shelter among the trees and to the removal of natural protection against storms and tsunamis. Freshwater sources are drained to lower the salt level of the farms and coastal communities are forced to move. It has been estimated that around 35% of mangrove forests have disappeared and some countries have lost 80% of their mangroves. The human activities causing the destruction of this tropical vegetation are aquaculture (52%, of which 28% is shrimp and 14% is fish), deforestation (26%) and the diversion of freshwater streams (11%).
Pressure On Wild Species
Contrary to what one might imagine, aquaculture does not reduce pressure on wild fish species. As practiced today, in many cases, it increases it.
- In intensive aquaculture, the high concentration of animals means that parasites and diseases spread easily. Farmed species, selected for their resistance, often survive only with the massive use of antibiotics and vaccines. But in the adjacent natural environment, local wild fish suffer greatly. For instance, recent research has shown that the area around a single typical British Columbia (Canada) salmon farm generated deadly sea lice at a rate of 33,000 times ambient levels, producing lethal infection of young wild salmon up to 70 km away.
- In many fish farms, enormous quantities of forage fish, fishmeal and fish oil are used to feed the farmed fish. Aquaculture often involves fattening up carnivorous fish such as many species of salmon and tuna. Clearly, the operation makes sense from a commercial point of view, as the farmed fish command much higher prices than the fish used to feed them, even when these forage fish (e. g. sardines, mackerel and herring) can also be eaten by humans. But in the end the quantity of fish used for feed is greater than the quantity produced, and the pressure on wild fish stocks remains high.
Given these issues, aquaculture cannot be seen as an alternative to fishing, particularly in developing countries, where very few people can afford products such as smoked salmon.
- Farmed fish are selected for characteristics that make them unsuited to living in the wild. Some farm fish escape from the ponds and put pressure on the natural environment. In some areas the escaped fish are more numerous than their wild cousins. They impoverish the genetic heritage and exacerbate the struggle for survival of native species.
- Some aquaculture businesses use genetic engineering techniques on the farmed species (genetically modified fish), usually without any external controls. Genetically modified tuna, salmon and tilapia are now being farmed. Research in this sector is growing rapidly in many countries around the world and is aimed primarily at sterilization, speeding up growth rates and improving resistance to cold and disease. It regards fish, shellfish and other marine organisms such as algae.
To date, we do not know what effects these practices will have on human health. However, the impact on the aquatic environment has been studied. Various organizations working to protect marine ecosystems point out that it is impossible to guarantee that these fish do not escape and say that their sudden presence in natural environments represents a potential disaster.
Another issue is the introduction of exotic species, which is a threat to the local ecosystem and causes unexpected problems for those who decided to introduce them. Chosen for their reproductive capacity, fast growth and water tolerance, genetically modified fish and exotic species have significant advantages over wild fish. Farm escapees threaten local species by eating juveniles, competing for food and shelter and spreading diseases and parasites.
Human Rights Violations
The industrialization of aquaculture is also leading to issues with human rights. For some years, serious concerns have been raised on the social impact of shrimp farms, which have seen a huge boom following a massive increase in global demand. According to the Environmental Justice Foundation, the shrimp industry is often guilty of serious abuses, such as land-grabbing, displacement of local people, violent intimidation, child labor and corruption of officials.
For example, in response to growing market demand, the intensive farming of oysters has increased significantly in recent years. In the 1980s, scientists developed a new sterile oyster known as the “four seasons oyster”. It could be consumed throughout the year, without the need to avoid the reproductive season. The case of farmed shrimp is another clear example of the disastrous effects of industrial aquaculture in the age of globalization.