The International Union for Conservation of Nature (IUCN) released a report on Wednesday that might impact the fate of declining coral reefs in the Caribbean. Most of the reefs may disappear in the next 20 years, but the IUCN believes there is a way to fix the problem.
Coral reefs have been in decline due to the absence of grazing species, such as herbivorous fish (i.e. parrotfish), sea urchins, sea stars, crabs, mollusks, and mesograzers. Without these creatures, the reefs cannot control excessive algae growth, which ends up killing corals and devastating the reef. A healthy reef relies on these grazing species to maintain algae growth so the coral can receive proper sunlight and nutrients.
The IUCN's report, "Status and Trends of Caribbean Coral Reefs: 1970 - 2012," was conducted in a joint effort with the Global Coral Reef Monitoring Network (GCRMN) and the United Nations Environment Programme (UNEP). It's the most comprehensive and detailed study of coral reefs, with contributions from 90 experts over three years analyzing more than 35,000 surveys from 90 Caribbean locations since 1970.
"The rate at which the Caribbean corals have been declining is truly alarming," said Carl Gustaf Lundin, Director of IUCN's Global Marine and Polar Programme. "But this study brings some very encouraging news: the fate of Caribbean corals is not beyond our control and there are some very concrete steps we can take to help them recover."
Climate change was originally thought to be the primary issue for the decline of coral reefs, but the report found that the significant loss of both parrotfish and sea urchin in the Caribbean (two of the main grazing species) has played a leading role. The researchers noted that an unidentified disease led to an immense decrease of sea urchin in 1983 and fishing throughout the 20th century contributed to the loss of parrotfish - even to the brink of extinction - in some regions.
The researchers found that the healthiest reefs possessed a plethora of parrotfish and were also protected from overfishing, excessive coastal pollution, tourism and coastal development, among other practices that exacerbate harm to a reef. Additionally, these healthy reefs were more resilient to the effects of climate change, which results in acidic ocean waters and coral bleaching.
So there remains hope for the declining coral reefs. Environmentalists can start by saving those, and then eventually figure out how to restore and establish new ones where the others were lost.
You can read more about the coral reef issue in the Caribbean in this Time Magazine article.
