Phys.org
15 May 2015
Grazing fish can help save coral reefs, but not all grazers are created equal, according to a Florida International University study published in Marine Ecology Progress Series.
A combination of factors is leading to the alarming loss of coral reefs worldwide, including ocean warming, disease and pollution. To make things worse, algae that can harm corals have also increased on many reefs. Fish and sea urchins that dine on the algae can help reefs recover but are unlikely to do the job alone according to FIU researchers Thomas Adam and Deron Burkepile.
The crystal clear tropical waters, which are home to coral reefs, are also a good environment for algae, which grow much faster than corals. If these algae are not quickly eaten by hungry herbivores they can smother adult corals and prevent young corals from finding a place to live.
The study, funded by the NOAA Coral Reef Conservation Program, examines impacts of herbivores on corals in the Caribbean, a region experiencing an increase in algae and significant loss of coral reefs.
In the Caribbean, algae began increasing in the 1980s, after spiny sea urchins—key grazers—were killed off by disease. Parrotfish eventually became the primary grazers on reefs in the region, but these herbivores are popular catches for fisheries.
“Clearly, parrotfish need to be managed for their impacts on reef ecosystems, and not just as a fishery resource” said Burkepile, a biological sciences professor who has spent most of his career studying imperiled coral reefs.