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It is tragic to bear witness as coral bleaching leeches the color from once vibrant ecosystems. However, sometimes the reef is able to recover and support a new community of aquatic life. Unfortunately, a new study has found that after a bleaching event, the community of fish on the coral reef can be altered dramatically and permanently.
The study found that bleached reefs had fewer predators like groupers, and more plant-eating fish like parrotfish. James Robinson, the leader of the study, said, “other reefs have reported the recovery of fish communities within 10 years, so we really didn’t expect Seychelles fish to get stuck in these new state.”
The study looked at the surveys conducted on coral reefs between 1994 and 2017. Analysis shows that the diversity of fish species on reefs changes dramatically when the reef recovers from bleaching. The change seems to stick around for at least 15 years. Unfortunately, the timespan between bleaching events has decreased to less than a decade in many parts of the world, meaning many reefs don’t have time to fully bounce back before another bleaching event occurs. Nick Graham, a professor of marine ecology at Lancaster University, points out, “The new normal for coral reefs will be reef fish communities which have fewer species and are dominated by herbivores and invertebrate feeding fish. This will alter the way coral reefs function, and the fishery opportunities for coastal communities adjacent to coral reefs.”
Scientists continue to search for ways that active management can help to rebalance these struggling ecosystems.