Parrotfish Can Help Save Coral Reefs, Study Says

Posted: Jan 23 2017, 10:40am CST | by , Updated: Jan 23 2017, 10:45am CST, in News | Latest Science News

 

Parrotfish can Help Save Coral Reefs, Study Says
Scientists extract a reef sediment core off Bocas del Toro, Panama. Credit: Scripps Oceanography/Richard Norris
 

Herbivorous fish like parrotfish can play a critical role in maintaining reef systems

Around the world, coral reefs are threatened by climate change and human activity. Threats such as aggressive fishing, ocean pollution and rising sea temperatures are having a direct and immediate impact on global reef systems. But luckily this situation can be reversed with certain strategies. 

By analyzing fossilized parrotfish teeth and urchins from the reefs of Caribbean side, researchers have found that parrotfish are critical to the general health of coral reefs, especially because they algae detrimental to coral reefs.

When there are more algae-eating fish on a reef, it grows faster. But overfishing is destroying this beautiful and voracious herbivore and putting coral reef systems at risk.

"Our reconstruction of past and present reefs from fossils demonstrates that when overfishing wipes out parrotfish, reef health declines.” Lead author Katie Cramer from Scripps Institution of Oceanography at the UC San Diego said.

Researchers have developed a 3,000 year record of the abundance of parrotfish and urchins in Caribbean Panama and found that the decline in herbivorous fish such as parrotfish over the last several decades gave rise to the population of algae, which can smother parts of coral reefs.

Coral reefs can live only in a balanced marine environment that offers lots of light, oxygen, clear water, low nutrients and steady temperature. However, when an algal bloom occurs near a coral reef, it blocks sunlight and other necessities required for their growth. 

To determine whether coral growth is affected by change in population levels of parrotfish that eat algae, researchers analyzed sediment cores ranging from prehistoric times as early as 997 BC to modern age up to 1980s. The fossil trapped inside the sediments allowed researcher to assess the populations of parrotfish during different periods of times. Researchers found that coral reefs’ growth accelerated when parrotfish were widespread on the reefs. However, the abundance of sea urchin did not have much effect on coral reef growth.

“The findings reveal that parrotfish indeed have a positive and critical role in coral health, a hotly debated issue in coral reef research that cannot be resolved without studies of modern reefs which have already been greatly altered by human activities,” said Cramer. 

“Using fossil record to analyze the natural state of reefs before human disturbance, we have conclusively shown that if we want to protect corals we have to protect the parrotfish from overfishing.”

“These results confirm that critical role of parrotfish in maintaining coral-dominated reef habitat and the urgent need for restoration of parrotfish populations to enable reef persistence.” 

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Hira Bashir covers daily affairs around the world.

 

 

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