Aquaculture is the farming of animals and plants that live in water for food. Fish farming is the principal form of aquaculture. Fish farms have provided subsistence for millions of people in China for over 2,000 years. Local small scale marine farming represents a clear cut benefit to the resident population when its yields are consumed locally.
In recent years, the world’s population has swelled and our appetite for fish has surged leading to a boom in the aquaculture industry.
Sadly, the ocean’s ability to produce fish is diminishing. With increasingly sophisticated fishing gear, our ability to catch fish has exceeded the ocean’s capacity to produce fish. Many of our favourite kinds of seafood are severely depleted.
Today, what you eat is just as likely to have been raised on a farm as caught from the wild.
Aquaculture is a viable method of protecting the natural stocks of aquatic species and removing the harmful effects of damaging fishing methods. The concept of sustainable aquaculture is absolutely beneficial and essential to sustain both human interests and those of the environment.
For example, Recirculating Aquaculture Systems (RAS) are able to use tiny amounts of water, produce large quantities of fish and have ZERO impact upon the environment…..which fishing methods can boast that?
Benefits of Fish Farming
Fish farming helps alleviate poverty in many parts of the world.
Over one billion people rely on fish as a main source of protein, many of them in developing countries. Much of the fish farmed in Asia is for domestic consumption. Fish farming for international markets has also blossomed and provides jobs in production, processing and sales.
The Dark Side of Fish Farming
Traditional farming methods for terrestrial animals have helped maintain our human population and to an extent preserved wild populations of ‘game’ animals. Why should aquaculture be any different?
- Domesticated animals (cows, pigs…) are fenced in and separated from other wild animals, but this is not so easy to do in the ocean. Captive tuna interact with wild stocks and in many instances infect wild stocks with diseases.
- Issue is between small scale “common sense” sustainable aquaculture used to feed a family in a developing country, and commercial projects used to fuel the insatiable high end seafood demands of international markets.
- Tuna farming projects are commercial, a few people make a ton of $ off of them, suck-up an absurd amount of resources, just so the upper echelon of society can continue to enjoy the “finer things in life”. Tuna farming is not feeding starving people in China.
- Issue is between small scale “common sense” sustainable aquaculture used to feed a family in a developing country, and commercial projects used to fuel the insatiable high end seafood demands of international markets.
- In some countries, coastal forests of mangroves were cut and replaced with shrimp farms. Mangrove forests provide critical habitat for commercially-important fish and shrimp, filter water and buffer the coastline against storm waves.
Other manageable issues:
Some fish farms allow uneaten food, fish waste, drugs and chemicals to pass into surrounding waters, where they can harm ecosystems and impair water quality.
To address this, the following is being practiced:
- Use closed recirculating systems to better control and treat effluents or waste water
- Add filter-feeders such as mussels near fish farms to remove micro-organisms and nutrients, thus improving water quality
- Minimise use of antibiotics and anti-parasite drugs with an array of measures to keep fish healthy, including vaccinating fish and stocking ocean fish pens with small fish that naturally feed on parasites
Farming predatory fish like salmon can use huge amounts of small, oily wild fish like anchovies, menhaden, mackerel and herring. These small forage fish are made into fishmeal and fish oil for feed. What happens then is more pounds of wild fish are consumed than the farm produces. Overexploitation of these small fish can deprive larger fish and other sea life of food.
Yes farming carnivorous fish is at this point ‘unsustainable’. However, taking them from the sea is even more unsustainable as a fish in the wild require far more protein to attain adult size due to the energy required to find the fish. Protein supplements are used in feeding some carnivorous fish (soya, etc) and there will hopefully be the option to use entirely sustainable feeds in the future.
To address this, the following is being practiced:
- farm vegetarian or semi-vegetarian fish such as barammundi
- feed predatory fish a semi-vegetarian diet supplemented with by products of fish destined for human consumption
Escaped farmed fish can pose serious threats to wild fish populations by competing with them for food and habitat and transmitting disease and parasites.
To address this, the following is being practiced:
- Farm specifies native to the region to reduce the potential harm from introducing a new fish species
- Used closed systems like tanks, rather than cages, to prevent escapes
- Developments in shrimp farming technology have meant that developed (high-tech) forms of aquaculture have produced ‘SPF’ (Specific Pathogen Free) stocks of shrimp that do not spread disease in areas that farming can only be done ‘extensively’ without bio-security (one example of thousands!)
Fish Farming 