ST. ANDREWS, Scotland, July 13 (UPI) -- Scottish scientists say overfishing in the South Atlantic Ocean off Namibia has resulted in a "jellyfish explosion" that's threatening the ecosystem.
The researchers from Scotland's University of St. Andrews, led by marine ecologist Andrew Brierley, say the number of jellyfish in the Benguela Current off Namibia far exceeds that of the once prolific commercially important fish stock of the area.
Brierley, leader of the university's Pelagic Ecology Research Group, says a similar phenomenon has occurred in the Black Sea and might soon occur in the Baltic.
The researchers say they calculated the numbers of the jellyfish by using echo sounders.
"We estimate the total biomass of jellyfish in the region to be 12.2 metric tons ... while the biomass of fish accounts for only 3.6 million metric tons," said Brierley.
He said the jellyfish biomass has also risen in numerous other locations worldwide, possibly the result of climatic change.
The scientists note that since jellyfish have few predators, once they become established it's difficult to revert to previous fish domination since jellyfish are predatory on fish eggs and juveniles.
The study appears in the journal Current Biology.
