The world's growing population and overfishing will mean around one billion people in developing countries will face shortages of fish, their most important source of protein, within 20 years.

According to analysis released by the Malaysia-based WorldFish Centre and the International Food Policy Research Institute, "only strong growth in fish farms will save the world from an even more critical condition".

The study estimated that fish currently accounts for around 7% of global food supplies and the primary source of animal protein for one-sixth of the world's six billion people.

WorldFish said in a statement, as reported by CNN, that some fish species will disappear from markets and the quality of seafood will decline, predicting also increasing disputes between countries over fishing grounds. "The decline in catches will have a serious impact on food security, nutrition and income in the two decades. Fish is the fastest growing source of food in the developing world yet demand greatly exceeds supply and the problem is growing," according to Dr Meryl Williams, Director-General of the Centre, as quoted in the report.

With 90 million more mouths to feed a year, fish stocks could not cope after 50 years in which average per capita consumption of fish has almost doubled. Aquaculture, or fish farming, offered a partial solution and under the study's most likely scenario, "global production will rise 1.5% annually until 2020." The report claims that two-thirds of the growth will come from aquaculture, which will provide 41% of the total food production by then - up from 31% five years ago.

Economists estimate that the fishing industry's inability to keep pace with demand will result in prices rising between 4% and 16% by 2020 at best, and in a worst case scenario by 26% to 70%.

The details were released ahead of an international conference held in the beginning of November in Penang, Malaysia. Policymakers, scientists, industry leaders and non-government organisations from 40 countries are scheduled to participate in the Conference.