Secondly, they've announced to their suppliers that within the next five years, all the wild-caught fish that Wal-Mart sells will come from sustainability-certified fisheries.

Ancient Sumerians kept wild-caught fish in ponds, before preparing them for meals.

There has been a concerted movement to captive breeding and certification programs for wild-caught fish.

Captive breeding presents an alternative to wild-caught fish.

Without doubt wild-caught fish are the best for breeding and there are now some very good specimens about.

Farming enables farmers to exploit the unpredictable supply of wild-caught fish.

The company also uses cage-free turkey, mid-western beef and 100% wild-caught fish.

Generally, fish are hardy only when they have been tank-bred, since wild-caught fish may take many generations to adapt to life in captivity.

On a dry weight basis, 2-4 kg of wild-caught fish are needed to produce one kg of salmon.

One proposed alternative to the use of wild-caught fish as feed for the salmon, is the use of soy-based products.