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Fish and Flowers

November 10, 2005

Fish populations worldwide have been decreasing. New research shows that this may have an unexpected effect on flowers.


Six degrees of pollination. I’m Bob Hirshon and this is Science Update.

We all know rain makes the flowers grow – but sometimes fish help too. That’s according to University of Florida ecologist Robert Holt.

He and his colleagues studied eight freshwater ponds. There, bees pollinate nearby flowers, while dragonflies prey on the bees. But fish control the dragonfly population by eating their larvae. Holt’s team compared the flora around ponds with fish to ponds without.

ROBERT HOLT (University of Florida):
Ponds that had fish in them tended to have fewer larval dragonflies, and fewer adult dragonflies…

…which meant more bees, and more frequent pollinations. Plants around fishless ponds, on the other hand, were more likely to be pollen-starved. The study suggests one way that the effects of overfishing may ripple onto land. I’m Bob Hirshon, for AAAS, the science society.