Humans have depended on water bodies since forever for food, dumping industrial and other wastes, and for other economic opportunities. Such human interventions have begun to take a massive toll on the marine ecosystems worldwide. Also, with the ever-burgeoning population, the demands for fish products have risen by a huge margin. In an attempt to get things under control, fishermen and other environmental experts have been engaging in practices of aquaculture and mariculture to produce more seafood and lessen the strain on the existing populations that are slowly inching towards extinction.
Aquaculture v/s Mariculture
While both aquaculture and mariculture are responsible for farming aquatic products under controlled conditions, aquaculture relates to freshwater whereas mariculture is identified with seawater. Mariculture is a specialized wing of aquaculture. Some of the common species that are grown in aquaculture include catfish, trout, carp, and tilapia. Fish farming is also done in landlocked ponds, plastic tanks by recreating the real environment found in the oceans. Popular aquatic species that are cultivated in mariculture include molluscs, seaweeds, crustaceans, and fin-fish. Mariculture involves farming of marine organisms in open oceans or tanks filled with seawater. Each aquaculture method has its own pros and cons.
Impact of Aquaculture and Mariculture on Marine Ecosystems
Let us look at how these fish farming methods have helped restore a balance in the ever depleting numbers of fish species in today’s times:
- Reliable Food Source: According to the statistics by Environmental Expert.com, fish farming is already supplying 50% of the fish used for consumption by the people. Aquaculture is one of the fastest growing food production sectors worldwide and it has contributed immensely to meet the current seafood demands. Moreover, some fish populations are also cultivated to be served as a feed for other carnivorous species. To a very large extent, aquaculture could reduce the need to find and catch wild fish to feed the human population. As per the Food and Agricultural Organization of the United Nations, 44.1% of the total fish production all over the world came from aquaculture in the year 2014.
- Availability: Fish farming can be set up almost anywhere where there is a clean water body source. Such source can be combined with regular irrigation practices and put to good use. As per the Aquaculture Production Technology, business corporations can lessen their costs when they combine fish farming with irrigation practices and also provide water and fish to the entire surrounding area. Fish farms are flexible and tanks can be placed on the seafloor or built on land as well.
- Low Environmental Impact: Studies conducted by National Oceanic and Atmospheric Administration demonstrate that aquaculture poses a low risk to the environment, with the immediate effect being brief. In some cases, it can even prove advantageous to the environment. Aquaculture is helpful in recycling the wastewater and sewage. In India, treated sewage is passed through ponds of duckweed followed by ponds of prawns and carp. When such treated sewage is passed through the ponds of organisms, such species gain nutrients from the waste as they clean water. This water can also be used for other agriculture purposes. Another example is the oysters that are cultured in situ and through aquaculture, the water in such lakes and ponds can improve. Though there are often problems that get attributed to aquaculture like water pollution, use of chemicals, and risks to the fish species, the governmental agencies believe that it is a long-term and sustainable solution to the marine fish populations all over the world.
- Other Benefits: Aquaculture is also used to harvest aquatic plants. These plants are also used to provide material which is used in pharmaceutical, nutritional, and biotechnology products.
Challenges of Aquaculture
While aquaculture has many benefits, there are also many challenges that it poses. Let’s look at them:
- The Environment: Land-based fish farms are in the form of tanks that contain dirty water which needs regular changing. The accumulation of fish waste and uneaten food in such fish tanks can degrade the quality of the wastewater and when such water is released into the environment it can result in algal blooms that cause eutrophication. There are also many other chemicals used in aquaculture operations like antibiotics, vaccines, disinfectants, etc.to keep the aquatic animals from getting sick and keep the surroundings clean. Of course, all of this depends on the method of cultivation being used, open-net or pen systems, or other closed contentment methods.
Impact of Biodiversity: By introducing farmed fish populations into the wild, aquaculture negatively impacts the existing biodiversity of marine or aquatic ecosystems. Farmed fish are known to have a lower genetic variation than the wild. So if they interbreed with the wild fish, it can result in a less genetically diverse population. If such farmed species become more established they can force out the native species and modify the aquatic environment.