Fish farming involves raising fish commercially in tanks or enclosures. Worldwide, the most important species in fish farming are carp, salmon, tilapia and catfish. According to the FAO, in 2008, fish farming produced 33.8 million tonnes of fish worth about $US 60 billion.
The increased global demand for fish has led to widespread overfishing in wild fisheries. Fish farming offers fish marketers another source. However, farming carnivorous fish, such as salmon, does not always reduce pressure on wild fisheries, since carnivorous farmed fish are usually fed fishmeal and fish oil derived from wild fish.
More information on fish farming can be found on Wikipedia: http://en.wikipedia.org/wiki/Fish_farming 
This week’s story refers to fish raised in cages. Fish cages are placed in lakes, lagoons, ponds, rivers or oceans to contain and protect fish until they can be harvested. Fish farming is called “offshore cultivation” when the cages are placed in the sea. Fish are stocked in cages, artificially fed, and harvested when they reach market size.
The fish farms in this story were established to counter diminishing stocks of wild fish. A Farm Radio Weekly article from September, 2010 (DR Congo: How overfishing leads to malnutrition, issue #129) deals with the effects of overfishing on human malnutrition. You can read it through this link: http://weekly.farmradio.org/2010/09/27/dr-congo-how-overfishing-leads-to-malnutrition-syfia-grands-lacs/ 
In some cases, reduced catches have led fishers to move back to the land and adopt a more sustainable approach to farming. “Permaculture promotes food security on Rusinga Island,” (FRW #218, September, 2012) shows how families can reduce their dependency on fishing when fish stocks fall. It is available here: http://weekly.farmradio.org/2012/09/22/kenya-permaculture-promotes-food-security-on-rusinga-island-by-sawa-pius-for-farm-radio-weekly-in-kenya/ 
This week’s story is based on the article “Farming in the Mauritius Seas,” which you can read here: http://www.ipsnews.net/2013/06/farming-in-the-mauritian-sea/ 
Many marine scientists think that the biggest single threat to ocean ecosystems today is overfishing. Scientists are warning that overfishing is causing profound changes in our oceans, perhaps changing them forever. Read more on the Greenpeace website: http://www.greenpeace.org/international/en/campaigns/oceans/overfishing/ 
Overfishing the lagoons of Mauritius and Rodrigues has had a destructive effect on coral reefs and the marine life they harbour. To increase the income of small-scale fishers and relieve pressure on depleted marine resources, an internationally funded program has encouraged fishers to stop lagoon fishing. Read more here: http://www.ruralpovertyportal.org/country/voice/tags/mauritius/fish 
But it is not just overfishing which reduces fish catches. Climate change is contributing to warmer seas and stronger waves. These conditions damage the reefs in and around which fish live and breed. This story is from Rodrigues, a tiny island 560 kilometres east of Mauritius: http://www.reuters.com/article/2007/06/07/us-mauritius-environment-idUSL074825020070607 
European fishers harvest fish off the coast of Mauritius. Many Mauritian fishers are not happy with the situation. Read more through this link: http://business.mega.mu/2012/08/10/mauritian-fishers-want-eu-vessels-out-their-seas/ 
In May 2013, politicians, scientists and fisheries managers from around the world attended the annual Indian Ocean Tuna Commission (IOTC) meeting in Mauritius. The IOTC is the organization charged by governments to protect tuna stocks in the Indian Ocean. Mauritian fishers protested the management of the Indian Ocean’s fisheries: http://www.greenpeace.org/international/en/news/Blogs/makingwaves/united-we-sail-mauritian-fishermen-greenpeace/blog/45041/