TIME Environment

Juvenile Coral and Fish Know When a Reef Has Gone Bad

World Without Corals
In this June 5, 2008 photo, fish gather on a coral reef in the Dry Tortugas National Park in Dry Tortugas, Fla. Numerous studies predict corals are headed toward extinction worldwide, some 50 percent of the Caribbean's corals are already dead, largely because of climate change, overfishing and pollution. Wilfredo Lee—ASSOCIATED PRESS

Too much seaweed and they're out of there

Baby coral and fish in the Pacific are able to detect both good and bad reefs, according to a Fiji-based study reported by the BBC. The study found that sea animals avoid reefs that do not give off the right chemical signals, because the failure to do so indicates that a reef is degraded.

According to the research, published in Science, when young coral and fish are presented with water samples taken from healthy reefs, and from reefs in overfished areas that are choked with seaweed, the sea creatures overwhelmingly choose the former.

Scientists say this could be a sign that simply designating a marine area as a protected zone may not be enough to help damaged reefs recover. The seaweed that has sprung up there may have to be removed as well.

“If you’re setting up a marine protected area to seed recruitment into a degraded habitat, that recruitment may not happen if young fish and coral are not recognizing the degraded area as habitat,” said Danielle Dixson of the Georgia Institute of Technology, the study’s prime author.

Once seaweed is removed, then damaged areas may start to see improvements, the BBC reports.

[BBC]

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