World’s fish and seafood stocks are at risk - Report

Overfishing, pollution and global warming have put the world's oceans at risk of losing underwater populations, possibly before the mid-century, an international team of fisheries experts and ecologists predicted.

In their report, which was published online in the Nov. 2, 2006, Science Express, the advance publication site for the journal Science, scientists said that if the current trend will continue than the supply of food for human will suffer. All commercial fish and seafood species will collapse by 2048, they said.

To examine how biodiversity loss influences marine ecosystem services across temporal and spatial scales, the ecologists analyzed local experiments, long-term regional time series, along with fishing data collected by the United Nations Food and Agricultural Organization (FAO) and other sources.

And after studying the data, they concluded that marine biodiversity loss is increasingly impairing the ocean's capacity to provide food, maintain water quality, and recover from perturbations.

"It's a gloomy picture," says lead author Boris Worm of Dalhousie University in Halifax, Canada. But, at the same time Worm said it is not too late to turn the situation around. “We see that diversity of species recovered dramatically," he said. People still have time to recoup these ecosystem benefits if they restore biodiversity.

To reach at a significant conclusion, Worm and his co-authors reviewed all data they could find on the issue. In 32 small-scale experiments, they discovered that higher diversity of either marine plants or herbivores led to benefits like greater ecosystem stability and 80 percent more biomass. A further review of 12 estuaries and other coastal ecosystems concluded the same trend.

But swift improvements are required, said Worm otherwise, he said, “We are seeing the bottom of the barrel.”

“When humans get into trouble they are quick to change their ways,” he continued. “We still have rhinos and tigers and elephants because we saw a clear trend that was going down and we changed it. We have to do the same in the oceans.”

As long as marine ecosystems are still biologically diverse, they can recover quickly once overfishing, pollution and other threats are minimized, the scientists say.

According to scientists, the populations under the threat are Cod, haddock, mackerel, salmon and tuna that will virtually disappear. Vast blooms of algae and plankton, some of which are toxic, worms and hordes of jellyfish will take place of them. Crustaceans, such as crabs and shrimps, may initially benefit, feeding on the dying, but will eventually collapse as they become the targets of fishing. Predators like seals, dolphins and sharks are also placed at risk.

The ocean provides about 130 million tonnes of food every year, and the researchers projected it to rise to between 180 million and 230 million tonnes by 2030. Besides providing food, life in the oceans also helped to clean pollution and recycle it, they said.

Impressed with the latest findings, Peter Kareiva, lead scientist for the Nature Conservancy said,"This analysis provides the best documentation I have ever seen regarding biodiversity's value," adding that "There is no way the world will protect biodiversity without this type of compelling data demonstrating the economic value of biodiversity."

In their report Worm and his colleagues urged for the formation of new marine reserves, sustainable management of fishing, and tighter control of pollution.