New York: Rising demand for seafood and other marine produce will lead to a collapse of commercial fish stocks by 2050 unless better management is introduced, a new United Nations report has warned.

"If rising living standards and inefficient methods of production and consumption intensify pressure on nature's natural resources - from fish, freshwater and the atmosphere to forests and fragile lands - globalization could become a spectacular failure rather than a saviour," UN Environment Programme (UNEP) Executive Director Achim Steiner said.

The UNEP Global Environment Outlook (GEO) Year Book 2007 notes that climate change may aggravate the fishery situation by increasing the acidity of oceans and seas and bleaching coral reefs, important nurseries for fish, and recommends a dramatic expansion of marine protected areas to prevent a collapse..

Experts have found that such areas, which currently cover just 0.6 per cent of the world's oceans, increase numbers of fish species by over a fifth and can boost catches in waters nearby.

The GEO Year Book stresses that the pace at which new marine reserves are being listed means the goal will be achieved three decades after the collapse of today's commercial fisheries.

"At the current rate of designation, the target will not be reached until 2085," it adds.

"Globalization is one of the defining issues of our time. Wealth is being generated on an unprecedented scale and millions are being lifted out of poverty. But a big question mark hangs over its future and its sustainability for current and future generations," Steiner said.