Environmental impacts of coastal fish farming

Seafood is an important part of global food production, but also a resource that has long been treated negligently. Catches from the sea, lakes and rivers have levelled off, while fish and shellfish farming has become more expansive. In the future, we need more aquaculture – but with less environmental impact. Cultivation in closed ecosystems can eliminate leaching of nutrients and chemicals and unwanted mixing with natural populations. Mobile fish farms in the open sea can be a transition to aquaculture that mimic natural shoals.

Seafood is both an energy efficient and healthy food, An annual production of about 150 million tons of important resources feeds the world’s growing population: providing the primary protein source for over a billion people.

About half of all the fish and seafood we eat is caught in the wild, and the other half is farmed – a rapidly growing sector – coming predominantly from open plantations in Asian rivers and coastal areas.

Both wild catch and cultivation have their respective environmental problems. Industrial fishing can lead to overfishing by larger outlets than stocks, long-term supports. The use of dubious and often indiscriminate trapping increases the risk, and even allows for species other than the target affected. Shrimp trawling, for example, can lead to over 80 % of the catch not being utilized.

According to the UN Food and Agriculture Organization, FAO, only 20% of wild fish stocks have a sustainable capacity, the rest are at or beyond the limit of what they can produce.

Cultivation – a viable option?

Growth in aquaculture has emerged as a more sustainable alternative to traditional fisheries. But the culture has downsides. It doesn’t solve the problem of over-fishing, because farmed carnivorous fish are generally given wild fish as feed. Examples include salmon, which is also farmed.

Another problem is local eutrophication and deterioration of water quality as a result of leaching from the often extremely dense individual farms; density also harm fish directly, and creates a breeding ground for pests and diseases, which also tend to spread to wild stocks.

New feed and closed systems

One hope to make tomorrow’s fish farming more environmentally friendly is to develop fodder for farmed carnivorous fish with a larger percentage raw material from alternative sources. It may involve plant, algae or yeast-based feed – where the yeast, for example, can be grown on waste products from the paper industry.

Another promising development is known as integrated “multitroft” aquaculture. There, several species are cultivated together, in more or less closed, balanced systems or food chains – where crops can be incorporated by the water and circulated in the culture vessels. In the latter case, the system grows without soil – a further development of a hydroponic solution. The balance of the ecosystem is maintained by nitrogen-based bacteria.


Taylor & Francis Improving Environmental Impact Assessmen
Book (Taylor & Francis)
  • Used Book in Good Condition

Wrong! Shrimp are lower in mercury

2006-01-21 07:40:26 by -0-

Q. What are the health effects associated with methylmercury exposure and who is at risk?
A. Nearly all fish and shellfish contain traces of mercury, therefore people can be exposed to methylmercury by eating fish. While most people’s fish consumption does not cause a health concern, high levels of mercury in the blood stream can have an effect on the developing nervous system of young children and unborn babies. Therefore, according to the 2004 FDA/EPA consumer advisory on methylmercury in fish, pregnant women, nursing mothers, women of childbearing age and those who might become pregnant and young children should follow this advice:
The advisory currently states:
Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury


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