Barbarians at the Gates: Jellyfish Are Taking Over the Oceans


Photo: Brian Sterling, CC
Happy World Oceans Day 2009!
What happens when you wipe out a species? Usually, another moves in the vacated space and takes over (sometimes making it hard for threatened species to recover). So it's not too surprising to learn that researchers are finding that overfishing and other human activities are not only making many marine ecosystems collapse (or close to it), but are also enabling jellyfish to attempt nothing less than an oceanic hostile takeover! Read on for more details.
jellyfish diver photo

Photo: Flickr, CC
The Jellyfish Invasion
Discovery News writes: "Jellyfish are normally kept in check by fish, which eat small jellyfish and compete for jellyfish food such as zooplankton, researchers said. But, with overfishing, jellyfish numbers are increasing."

But there's worse: "climate change could also cause jellyfish populations to grow. The team believes that for the first time, water conditions could lead to what they call a "jellyfish stable state," in which jellyfish rule the oceans."

Nitrogen run offs, such as in the gulf of Mexico, also help jellyfish by causing phytoplankton blooms. These blooms cause low-oxygen deadzones where little car survive... except Jellyfish.

How to Fight Back
It's pretty obvious when you read the causes of the problem what the solutions are: Stop overfishing, control nitrogen run offs, etc. On top of that, ships should be careful not to transport jellyfish in their ballasts.

Via Discovery News, ABC Science News
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