60 Minutes and Cuban Reefs

Underwater photo of elk horn coral and reef fish in the Gardens of the Queen marine park in Cuba.

Elkhorn coral and reef fish in the Gardens of the Queen marine park in Cuba.

Hats off to CBS for the recent “60 Minutes” segment on the coral reefs of the “Gardens of the Queen” (Jardines de la Reina) in Cuba!

The Gardens of the Queen is a spectacular national park off the south central coast of Cuba.  EDF has had the privilege of working with Cuban scientists and resource managers in the park for several years.  Just this past November we teamed up with Cuban partners there to host an international workshop on fisheries management and marine protected areas.  In 2012 we will partner with Cuban scientists to study the benefits on fish populations from restricting most fisheries inside the park.

The 60 Minutes piece highlights the good work Cubans are doing to protect marine ecosystems and the challenges that lie ahead.  I was especially impressed with the work of CBS producer Anya Bourg to ensure that the piece was rigorous – as much as possible – in its treatment of complex scientific issues.  Explaining complicated and often subtle relationships in plain and compelling language is a real feat!

For the most part, 60 Minutes got it right.  Let me expand on two key themes from the piece, based on work we are doing with Cuban scientists to help understand the lessons from the Gardens of the Queen.

The coral reef ecosystems of the Jardines are spectacular, and in better shape than most other coral reefs around the Caribbean.

The scientific literature – and my personal experience diving the reefs of the Gardens and elsewhere around the Caribbean for many years – confirms the central points in the report.  The reefs in the Jardines contain unusually large numbers of top predators including sharks and large groupers and snappers, and unusually large amounts of fishes of all species.  While there are other places in the Caribbean that one can go to see diverse small fish communities, sites with high abundances of large fishes are quite rare.  Few – if any – locations offer larger total amounts of fish of all species.

Sharks are vital to the health of coral reef ecosystems in the Park

Sharks are vital to the health of coral reef ecosystems in the Gardens of the Queen.

A scuba diver in the Gardens will see Caribbean reef sharks and silky sharks too numerous to count, along with frequent nurse sharks, and occasional lemon and blacktip sharks.  Most weeks – depending on season and other factors – visitors have multiple whale shark encounters.  We encountered five in one day in November.

Large groupers are common, including the true behemoths, the goliath groupers.  While goliath groupers are making quite a comeback in some places in Florida, they are mostly still babies, with large animals still quite rare.  In the Gardens, other groupers – black, Nassau, yellowmouth, yellowfin, and tiger, among others – are abundant at diving depths, along with all possible snappers, many fished out, or nearly so, in most Caribbean locales.

Smaller species are present in great diversity and abundance, including the parrotfishes and other herbivores, the sanitation engineers of the reef, greatly diminished in many places.  We recorded totals of 124 and 127 fish species in short trips to the Jardines in 2010 and 2011, respectively, without any night-diving or specialty habitat diving that would have expanded the numbers dramatically.

Cuban Research Vessel at sea in the Gardens of the Queen.

Cuban Research Vessel in the Gardens of the Queen.

The corals in the Gardens present a somewhat different story, reflecting the challenges faced by corals across the Caribbean.  Historical epidemics of diseases of corals that devastated total coral cover around the region affected every reef – no completely “pristine” reefs exist.  The massive dieoffs of long-spined urchins that caused algal overgrowth of many reefs occurred here, too.  Staghorn coral (Acropora cervicornis) and elkhorn coral (A. palmata) were also significantly affected in the Gardens.  Together, these factors have reduced coral health everywhere in the Caribbean.  Total coral cover in the Gardens is probably less than half what it was in the first half of the 20th century – lower than the past, but still better than most other places in the region.

That said, significant areas in the Gardens retain their elkhorn coral reefs, and the species seems to be holding its own there, reproducing, apparently both by larval settlement and resheeting.  Urchin populations have also rebounded to considerable numbers.  The high abundances of fish species that help control overall community structure – especially herbivores and top predators – is also obvious.

The bottom line is that while there are no “pristine” reefs anywhere in the Caribbean, many reefs in the Gardens of the Queen are among the healthiest, retaining many of the attributes reefs will need to persist into the future.

High quality reefs in the Gardens may prove more resilient to the challenges ahead, and that may provide important lessons for future management of coral reefs.

The bad news is that corals around the world face massive challenges associated with historical damage exacerbated by new threats associated with a warming, rising and acidifying world ocean.  In addition, intensifying storms of the type that have wrecked havoc in other notable Caribbean diving destinations like Belize, Bonaire and the Virgin Islands also threaten Cuba.  In recent years, Cuba has been in the cross hairs of numerous hurricanes and other tropical storms.

Furthermore, “bleaching” of corals occurs when otherwise symbiotic microalgae are driven out of their homes inside coral organisms by too-hot water.  Bleaching often leads to coral death.  Increasingly, bleaching has occurred throughout the Caribbean during hot summers, including in Cuba.

To make matters worse, the recent plague of voraciously predatory and venomous Pacific lionfish throughout the Caribbean – caused by “biological pollution,” the accidental and perhaps purposeful releases of these animals in U.S. waters – not only adds another threat to coral reef ecosystems, but another management complexity.  Changing ecosystems are vulnerable to invasion by novel opportunistic species.  Many scientists fear that lionfish are just the first of many such invaders.  I personally counted 34 lionfish on a single transect while diving in the Gardens in 2010.

Without careful management, most coral reefs seem doomed.

The good news is that elkhorn corals persist in some places in the Gardens and elsewhere, creating an opportunity to manage for future reefs, if we can understand the lessons from this survival.  When coral reef scientists from the U.S., Mexico and Cuba get together to compare notes about the future of shared reefs of the Caribbean, identification of the factors that result in persistence rise invariably to the top of all research wish lists.

Recent scientific papers directly link total fish biomass to a whole suite of coral ecosystem health indicators.  Admittedly, that groundbreaking work was done in the Pacific, but there is no reason to expect it won’t work in the Caribbean.  Put simply, most marine ecologists believe that reefs with more intact trophic structure and higher fish biomass overall will be healthier in the future, and more resilient to climate change.

In addition, corals can recover from bleaching, when conditions allow their endosymbionts to recolonize the corals.  In the Gardens, coral mortality after bleaching seems low, according to the Cuban scientists who are studying this phenomenon.

The Cubans – and other resource managers around the Caribbean – are also working hard to understand the implications of the lionfish invasion and identify management options to negate its impact, as a general lesson for the future of reefs in changing seas.  A tiny glimmer of hope: although young lionfish are still all over the place in the shallow waters, our informal censuses of lionfish on some reefs in the Gardens contained fewer individuals in 2011 than in 2010.  Perhaps the large populations of large predatory fishes can help modulate this threat.  Time will tell.

While no one can know today which reefs will persist – or for that matter, what their biological composition will be in the future – the presence of these unusually high-quality sites within the Gardens gives good reason for hope for the future, if we can just learn the lessons in time!

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