Aquaculture and environmental
Aquaculture is the fastest-growing food sector in the world.
Back in the 1970s, only 6% of the world's food fish came from aquaculture. By 2006, that share had nearly doubled, according to a biennial report on the state of world fisheries and aquaculture published last month by the Food and Agriculture Organization of the United Nations.
Today, more than 53% of the world's consumed seafood is produced by aquaculture farms.
Over the past few decades, the environmental impact of aquaculture has become a popular discussion topic that is not always positive. In particular, there are still reports in the media about numerous cases of environmental disasters of various levels associated with the activities of salmon farms in Norway and Chile.
It is worth noting that the environmental impact of aquaculture is completely dependent on the species being grown, the intensity of production and the location of the farm.
In addition, new strategies and technologies have emerged that have proven the feasibility of sustainable aquaculture development without depleting natural resources. In the past, when the aquaculture industry was just beginning to develop, one of the main factors hindering the reduction of the environmental impact was the main goal of fish farming - to increase food security.
This development vector has led to environmental problems associated with the accumulation of organic substances and waste products in water, the impact of fish farms on local fisheries (the spread of diseases and shoots of farmed fish), as well as environmental degradation due to the location of farms. (based on www.aquaculturealliance.org)
The impact of cage aquaculture on the water is described in detail in an article by the World Wide Fund for Nature.
From an economic point of view, cage farming is the most cost-effective type of aquaculture, but its negative impact on the environment is multifaceted and significantly surpasses all other types of aquaculture.
So, mass diseases in cage farms are found regularly in different parts of the world. Hundreds of thousands of salmon have died in recent years on the farms of Chile and Peru. For five years from 2007 to 2012 in cage aquaculture in Norway, between 473 and 509 cases of outbreaks of infectious diseases were reported annually. In the summer of 2015 in Russia on the Kola Peninsula, a disease began that led to the mass death of fish. They could not efficiently dispose of hundreds of tons of dead fish and carried out its unauthorized burial in the Murmansk region, including in the immediate vicinity of the Kola salmon river, which caused serious environmental damage.
Unfortunately, all known cases are just the “tip of the iceberg” of the whole range of environmental threats posed by cage aquaculture, and which are usually not so noticeable to the general public.
These environmental threats are well studied and described in detail in the scientific literature:
- organic pollution (eutrophication) - excess nutrients from food and fish excrement from salmon farms increase the level of organic matter in the water, bottom sediments form, which is extremely negative for marine ecosystems;
- chemical pollution - farms use antiparasitic preparations, antifouling agents, antibiotics, feed colours, which can have unpredictable consequences for marine organisms and human health;
- genetic pollution - escaped farmed salmon can compete with wild fish and interbreed with native wild herds, worsening the genetic diversity of salmon.
- infectious diseases can be transmitted to wild populations.
In addition to these main factors, other negative aspects of cage aquaculture can be noted:
- spatial competition - the most valuable and productive sections of sea bays and lips can be allocated for cage farms;
- conflicts with local predators - cages with fish attract seabirds, seals and other marine mammals, with which fish farmers are forced to fight by various methods, up to shooting;
- using aquatic biological resources as feed - aquaculture depends on fishmeal and fish oil, which puts additional pressure on the world's fisheries. Fish caught in order to make fishmeal and fish oil out of it currently make up one-third of the world's catch.
Thus, the high profitability of cage aquaculture is associated with even higher economic and environmental risks, which can invalidate all its advantages. (based on wwf.ru)
Fortunately for the aquaculture industry and for the well-being of the planet, significant progress has been made in the science and technology of fish farming, in particular:
- The practice of locating fish farms in areas with strong currents to disperse the generated wastewater, as well as periodically changing the location of farms to prevent exposure to one specific area to a greater extent than others.
- The use of antibiotics is reduced, safe and effective vaccinations have been developed and are now widely used.
- To reduce the shoots of farmed fish from farms that happen periodically, underwater cage tracking cameras are used.
- The problem of reducing the use of aquatic biological resources for the production of feed is also under solution. Technology has been developed to replace fishmeal with raw materials from vegetable proteins, and raw materials from processing enterprises are also used, the production of which does not require the direct catch of krill, anchovy and other non-commercial fish.
- Ground-based aquaculture facilities based on recycled water supply technology are widely developed and implemented, eliminating the risks of cage farms and the emission of substances that have a negative impact on the environment.
In conclusion, can be noted that the positive dynamics of aquaculture development and the growing indicator of the excess of farmed fish over fish which harvested in natural sources requires further development.
In particular, it is necessary to carry out work to optimize existing and develop new technologies and measures to reduce the impact on the environment and natural resources.
It is necessary to carry out large-scale breeding work aimed at domestication of valuable fish species that demonstrate high growth rates, increased weight and stable health indicators.
In our understanding, the development of aquaculture in this vector is the foundation of world food, as well as the basis for the restoration of world water resources.
Despite the long existence of aquaculture as a historically established food industry, its level of development is in its infancy and has promising prospects for meeting the food needs of the world's population.