New research by the Universities of Exeter and California Davis has indicated that damaged Caribbean reefs will continue to decline over the next 50 years if steps are not taken to save parrotfish and the herbivorous urchin, Diadema Antillarum.
The research team has also appealed for the introduction of alternatives to ensure proper marine and sewage management. Published today's issue of Nature, the study claims that coral reefs are becoming unhealthy and overrun by seaweed.
In the 1980s, reefs in the Caribbean were hit by the devastating impact of the near-extinction of the herbivorous urchin, Diadema antillarum, with devastating results. Along with parrotfish, this grazing urchin kept seaweed levels down, creating space for coral to grow. Parrotfish are now the sole grazers of seaweed on many Caribbean reefs, but fishing has limited their numbers. With insufficient parrotfish grazing, corals are unable to recover after major disturbances like hurricanes and become much less healthy as a result.
According to Professor Peter Mumby, the lead author of the study, "The future of some Caribbean reefs is in the balance and if we carry on the way we are then reefs will change forever. This will be devastating for the Caribbean's rich marine environment, which is home to a huge range of species as well as being central to the livelihood of millions of people."
The paper argues that in order to secure a future for coral reefs, particularly in light of the predicted impact of climate change, parrotfish need to be protected.
Parrotfish are frequently caught in fish traps that are widely used in the Caribbean, with many ending up on restaurant diners' plates. Mumby says practical steps can be taken to protect parrotfish and help reef regeneration, and has recommended a change in policy to establish controls over the use of fish traps, which parrotfish are particularly vulnerable to.
The US Environmental Protection Agency, the Royal Society, the Natural Environment Research Council and the National Science Foundation funded the research.