There are now around 6 thousand million people in the world, up from 1.5 thousand million in 1900. Three out of four of these people are living in the poorer regions of our planet, in countries that are still industrializing, still trying to build up their export trade, and struggling to feed a fast-growing population. Planners are trying to give these people jobs, find places for them to establish a home, and offer them a decent life.

Many developing countries are looking increasingly towards the sea to provide them with a means of feeding their populations over the coming decades. This will be a major challenge.

Marine fisheries still provide by far the most important source of wild protein. Subsistence communities around the world depend on them, some exclusively. Fish, molluscs and crustaceans are the major food sources, although marine algae is important, particularly in the Far East, both as food and a source of medicines.

But since 1989 capture fisheries have steadily declined, an alamring trend that calls for an unprecedented level of commitment and cooperation among the world's fishing nations if it is to be reversed.

Scientists differ in their explanation for the slowdown. Many blame overfishing, others pollution, some say it is part of a natural cycle beyond our control. They also disagree on how much of a harvest we can expect from the seas. Some pin their hopes on persuading people to eat different kinds of fish --only a dozen different types are consumed in large numbers. Others point to the explosive growth of aquaculture – fish breeding and cultivation in fresh and salt waters – as a way ahead.