EcoAlert: Jellyfish Blooms Threaten Ocean Food Chain

20110607_jellies Scientists warn explosive growth of jellyfish populations in oceans and seas around the world are a sign of marine ecosystems being devastated by overfishing, nutrient pollution, global warming, and the introduction of non-native species.

"Jellyfish are voracious predators," said lead author Rob Condon of the Dauphin Island Sea Lab (DISL) in Alabama, U.S. "They impact food webs by capturing plankton that would otherwise be eaten by fish and converting that food energy into gelatinous biomass. This restricts the transfer of energy up the food chain, because jellyfish are not readily consumed by other predators."

Populations of jellyfish are exploding in seas and oceans around the world raising anxious concern about the health of marine ecosystems. Off the coast of France, aggregations of jellyfish have sunk 500-pound fishing nets. In Japan, jellyfish have clogged the water intakes of nuclear power plants. In the Gulf of Mexico, jellyfish are competing with humans for the larvae of commercially important species such as shrimp. One gulf shrimp boat captain said that in some places, the jellies are so thick "you can almost walk across the water on them."

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