The reefs are racing seaweeds for survival

Oct 9, 2008 14:55 GMT  ·  By

After noticing the rapid decline rate of coral reefs in all habitats, international scientists began extensive study on the conditions a reef must have in order to survive and to expand. For that purpose, they placed several underwater cages on designated locations in the Caribbean Sea, each of them containing two different species of fish. In some cages, the reef regenerated and expanded, while in other ones it died off, suffocated by seaweeds.  

It has been known for several years that the coral reefs worldwide depend on plant-eating fish to survive ever-growing seaweeds. But until now, there was no plausible theory as to how many fish were needed or the species combination a reef needed to fully recover. Following a nine-month-long survey by Mark Hay, the Harry and Linda Teasley Professor of Biology at the Georgia Institute of Technology and scientist Deron E. Burkpile, at Florida International University in North Miami, the results showed that the correct combination of herbivorous fish actually helps the reef gain much of its strength back over short periods of time.  

The portions of the coral reef under the cage containing the redband parrotfish (Sparisoma aurofrenatum) and the ocean surgeonfish (Acanthurus bahianus) showed signs of regeneration and eventually expanded by more than 20 percent. This growth rate is highly unusual for the Caribbean area, although, at some point in the last century, the reefs here were 40 to 60 percent more dense and healthy than they are now.  

Analyzing the data they collected from the study allowed the researchers to hypothesize that, by putting together the right combination of herbivorous fish, the reefs could be cleansed of seaweed and brought back to life. Admittedly, their previous sizes and density are gone forever, due to pollution, extensive fishing, global warming and other human-related activities, but cases such as that of the reef in Fiji can be substantially improved through intervention.