Never before has so much fish landed on people's plates than in recent years. In 2007 worldwide fish production stood at 160 million tons - - eight times as much as in 1950.

Up to 2030 annual production will have to increase by an additional 40 million tons if per-capita consumption is to remain the same despite the increasing world population. This is the estimate published by the Ifo Institute for Economic Research at the University of Munich.

Luise Röpke and Jana Lippelt  say in a paper published in Ifo Schnelldienst (in German) that an expansion in production by 2030, is hardly achievable by means of conventional fishing. According to the UN Food and Agriculture Organization, 70 per cent of the important fish populations are "maximally fished", "over-fished" or "exhausted". This means that these stocks are already being fished at levels that must not be exceeded in the long term or that the yields are already below historical peaks despite greater fishing efforts. In some important fishing grounds, such as in the western and eastern mid-Atlantic or in the north-eastern Atlantic, already up to 100 per cent of the examined fish species fall into these categories.

Faced with this development, aquaculture is increasingly gaining importance. More than a third of the worldwide fish production is already being cultivated under such controlled conditions. With an annual growth rate of seven per cent, aquaculture is one of the fastest growing agricultural sectors. In addition to its contribution to food production, aquaculture is also an increasingly important economic factor. Worldwide about nine million workers in this field account for €80 billion in turnover every year.

However, the authors say the ecological balance sheet of aquaculture is problematic in many respects. In particular the feeding of the fish with fish meal from conventional fishing leads to further stress on fish in the oceans. Another problem is the use of antibiotics in illness-prone cultures with a high density of fish.

For this reason they say that it is necessary to develop sustainable production methods without the use of fish meal and with fewer burdensome intrusions in environment. Corresponding projects are being supported by the World Bank, for example. If these projects are successful, aquaculture could make an important contribution to the food supply, at the same time protecting the environment and the natural fish populations.