Fewer Fish Leads to Jellyfish Explosion

In a region off the west coast of Africa in the Atlantic Ocean, heavy fishing in recent decades has depleted fish stocks while leading to increased numbers of jellyfish.

Now with some hard data in hand, scientists are calling it a jellyfish explosion.

In fact the jellyfish are so numerous in the study area that they now represent more biomass than all the fish combined. Their numbers, ironically, are beginning to "significantly interfere with fishing operations," the researchers report in the July 12 issue of the journal Current Biology.

Overfishing and climate change might both contribute to the phenomenon. Jellyfish have few predators, the scientists say, so if fish are depleted and nutrients are available, the jellyfish do quite well.