Shark fishing on coral reefs can threaten herbivorous fish that help to protect the reefs after natural disturbances such as cyclones, according to new study findings.

In areas where commercial shark fishing has occurred, there were declines in parrotfish and other types of herbivorous fish, and increases in carnivores, such as snappers.

Herbivorous fish help to clean and maintain coral reefs by eating algae off of the coral. “They are really essential to the recovery process of reefs,” said Dr. Jonathan Ruppert, a post-doctoral researcher at York University and lead author on the study. “Herbivores help in removing algae from the reef to allow coral to repopulate or reestablish on the reef.”

Researchers looked at the effects of the presence or absence of sharks before and after a traumatic event, either a cyclone or coral bleaching – a process through which warmer water temperatures cause algae to disappear from the corals. They found there was a link between the presence of sharks and populations of other types of fish further down the food chain. Full Article »