Maintaining fish stocking levels and overall biomass around coral reefs can play a vital role in their survival and prevent their eventual collapse. According to a new study overfishing and the loss of the overall reef biomass can generate a predictable sequence of events that lead to the collapse of reef ecosystems.
“The consequences of overfishing can be severe to the ecosystem and may take decades to recover, but hundreds of millions of people depend on reefs for food and livelihoods, so banning fishing altogether isn’t a reality in many nations,” said Dr Nick Graham of the ARC Centre of Excellence (ARC CoE) for Coral Reef Studies and James Cook University.
The research shows the fish biomass living on a reef declines over pressure from excessive fishing. Once certain points are crossed as the numbers dwindle, it gets harder to get back and recover.
“For example, you see patches of weeds replacing coral, you see more sea urchins devouring the coral, you see a general decline in the species richness on the reef, and you see less coral cover,” added Graham. “The loss of hard corals is actually the last stage in the collapse of the reef system. Though many people take it as a major warning sign, in fact, by the time you see the loss of live coral cover, it may be already too late to save the reef,” he added.
If fish stocks can be maintained at certain levels, the chances of a reef crossing one of these points of no return and remain a healthy reef and sustainable fishery for a longer time. The study was published in the Proceedings of the National Academy of Sciences of the USA (PNAS).
[via BioScholar; Image: Australian Institute of Marine Science (AIMS).]