According to recent study published in the journal Proceedings of the National Academy of Sciences, limiting parrotfish catch could provide a solution to the rapid decline of Caribbean coral reefs. Based on the work of researchers from the University of Queensland, the study is the first of its kind to suggest specific science-based regulations for Caribbean parrotfish fisheries.
The Caribbean is home to nine percent of the world’s coral reefs. A devastating cocktail of factors, including climate change, overfishing and pollution have increasingly affected the area in recent years. As a result, coral cover in the Caribbean has decreased by over 80 percent. This statistic is likely to worsen as the symptoms of climate change continue to plague the region. Coral bleaching as a result of rising sea temperatures is a particular concern. Study co-author Peter Mumby warns that the future of Caribbean reefs depends on how well they are able to recover from bleaching events.
Recovery is possible if we allow new corals to repopulate and grow on the skeletons of the bleached reef. However, these fragile new structures must compete with algae, which often suffocates the new coral and prevents any further growth. The reefscape becomes barren and lifeless. Herbivorous fish like the parrotfish provide a solution to this problem, acting as crucial gardeners for the reef by removing algae and giving new corals the chance to grow.
Limiting Parrotfish Catch
In the Caribbean, parrotfish are a key herbivorous species, spending up to 90 percent of their day feeding on algae. However, local fisheries specifically target them. As their numbers decline, the Caribbean reefs become less likely to survive an increasingly uncertain future. Mumby and his fellow researchers investigated how many parrotfish fishermen can remove from an ecosystem before they affect it negatively. In this way, scientists ascertained what regulations could help parrotfish fisheries remain sustainable.
To do this, the team developed a model to predict how different fishing regulations could affect parrotfish populations. Then they tested the accuracy of their model against known case-studies, in which altered fishing regulations triggered a dramatic change in regional fish populations and reef health. As a result of their findings, the team recommended a minimum size restriction of 12 inches (30 cm). They also recommended limiting total catch to 10 percent of the mass of the Caribbean parrotfish population.
Is it working?
Several Caribbean countries, including Belize, Bonaire and Turks & Caicos, have already banned parrotfish fishing. These countries are home to some of the healthiest reefs in the region. They illustrate the positive impact that these suggested fishing regulations could have. According to Mumby, fishermen would be wise to adhere to the regulations if they are implemented. “The more we do to maintain healthy coral reefs, the more likely it is that fishers’ livelihoods will be sustained into the future,” he says. Failure to do so could mean a threefold reduction in future catches.
While the current model applies specifically to Caribbean reefs, scientists and conservationists could manipulate it to help other areas on a case-by-case basis. In particular, Mumby hopes that limiting parrotfish catch could be relevant for Australia’s beleaguered Great Barrier Reef. This UNESCO World Heritage Site is currently in the middle of a major coral bleaching crisis.
