Overfishing, coastal pollution may be main threats
Research taking place in Little Cayman could hold the key to the survival of coral reefs in the Caribbean and the colorful marine life they support.
As reports warn that the region’s reefs could disappear almost completely within the next 20 years, a ray of hope comes from the Central Caribbean Marine Institute.
Coral cover has actually been increasing around Little Cayman in the past five years, bucking the regional trend that has seen widespread coral die-off on reefs – often compared to rainforests because of the biological diversity they support.
Carrie Manfrino, president of CCMI, said the secrets of Little Cayman’s success could hold the key to the survival of the species.
Initial studies suggest that controlling overfishing and reducing coastal pollution could be key factors.
Researchers say ocean warming caused by climate change is a threat to reefs – but it is just one part of the problem.
By focusing on factors within local control, like strict management of fisheries, they believe authorities can help contribute to the recovery of reefs, which are estimated to be worth around $350,000 per hectare (2.5 acres) per year to island economies.
There are relatively few pockets of reef worldwide where corals are recovering. These ecosystems are likely to become the locus of scientific activity over the coming years to determine what makes them special.
Ms. Manfrino said, “We have a big project ongoing right now funded by the Darwin Initiative to try to understand why these reefs are recovering and what is so special about these habitats where we are seeing coral recovering.”
She said there is little local authorities could do to control climate change or the occurrence of ocean warming events like “El Niño” which have been blamed for bleaching events that have wiped out coral colonies in the past.
“If management action is taken, including restoring depleted parrotfish populations, reducing coastal population and halting overfishing, coral reefs will have the chance to recover and resist the impact of climate change,” added Ms. Manfrino.
She recently co-authored a report, “Status and Trends of Caribbean Coral Reefs: 1970-2012”, along with a global research team, also including the Cayman Islands deputy director of the Department of Environment, Tim Austin.
The report warns that the region has lost half its coral cover since the 1970s and predicts that corals could all but vanish within 20 years in the Caribbean.
Ocean warming and acidification are drivers of coral bleaching and degradation too, but “local stressors” such as overfishing have been most responsible for the catastrophic decline of Caribbean corals, says the report.
An earlier study by CCMI on Little Cayman showed the island’s reefs lost 40 percent of their corals in the aftermath of the 1998 El Niño event, which warmed ocean temperatures and wreaked havoc on corals worldwide. The study showed that corals in Little Cayman defied expectations by completely bouncing back, repopulating the isolated reef system.
Now research is focusing on identifying the specific reasons for the resilience seen in Little Cayman but not elsewhere.
CCMI, in partnership with the DoE through the U.K.-funded Darwin Initiative, is also investigating methods of repopulating the reefs with threatened staghorn coral species, experimenting with growing corals in a kind-of underwater nursery.
They will also be conducting lab experiments to simulate future projections for ocean acidification and other threats to corals.
““We are trying to better understand how local staghorn coral resists climate change impacts in the face of additional local stresses.
“We have improved the odds of survival for the coral by testing different strategies for fragmenting the colonies. The work is intensive and our conservation scientist, Katie Lohr, must regularly care for and monitor the corals.
“It is like tending a delicate vegetable garden, but it requires many hours under water,” said Ms. Manfrino.