Sir – Your article on aquaculture (“Come, friends, and plough the sea”, January 3rd) was spoiled by surprisingly many misunderstandings and errors.

The article overstated world aquaculture production, which was in fact estimated at 47.8 million (not billion) tons in 2005. Also, salmon farming has low CO2 emissions (3 kgCO2 per kg produced) when compared, for example, to beef production (16 kgCO2 per kg produced). And salmon farming has not infected Norwegian rivers with Gyrodactilus salaris. Rather, the tragedy was caused by a mistake in re-cultivation regimes in the early seventies.

It is misleading to say that “tiddlers”, used to produce fishmeal, “would grow into bigger, commercially valuable fish”. In fact, the fishmeal industry specifically targets small-sized forage fish. And today, it takes about one kg of compound feed to grow one kg of salmon. So, with about 30 % fishmeal in the feed, the use of fishmeal per kg of salmon produced is 0.3 kg, not 3 kg as stated in your article.

Sustainable fish farming is important in helping to feed the growing population of the world. This young and fast growing industry should be supported to overcome its challenges, not undermined by poor journalism.  For readers interested in learning facts and perspective of aquaculture I highly recommend: The Economist, August 03,”The promise of a blue revolution”.  Great journalism.

Kjell Bjordal
Managing Director,
EWOS Group.