Bearded 'super' fish helps salvage ocean dead zone

Last Updated: Sat, Jul 17, 2010 07:10 hrs

Scientists have discovered that a resilient fish, thriving in an inhospitable, jellyfish-infested region off Africa's south-west coast, is helping to keep the local ecosystem going, and preserving an important fishery.

The Benguela ecosystem, off the coast of Namibia, was once rich in sardines, but overfishing and environmental factors caused the population to crash, and the region was invaded by algal blooms and swarms of jellyfish.

The algae have consumed almost all the oxygen in the water, and the upper waters are thick with jellyfish and algae.

Now, Anne Utne-Palm of the University of Bergen, Norway, and colleagues have found that bearded gobies spend the daylight hours at the very bottom - the only backboned animals in the area to do so. Their stomach contents reveal that they feed off dead algae fallen from the surface, and also on the jellyfish.

The team found that the gobies could survive for hours in the oxygen-poor waters by lowering their metabolic rate, and could head up to the surface to take in oxygen.

"It's good to see that some ecosystems can be sustained throughout this sort of hypoxic event, but I suspect that in a lot of environments there isn't a 'super-goby' around to help out," New Scientist quoted Daniel Jones of the National Oceanography Centre in Southampton, UK, as saying.The sardines may have gone, but horse mackerel and hake survive in the area by feeding on the gobies, and are regularly fished by humans.

"If it weren't for the gobies, the human fishery would be in a worse condition than it is," he added.

The study has been published in Science. (ANI)