Even though at first appearance corals may look like plants or even rocks, they are in fact animals, related to sea anemones and jellyfish. Corals live in colonies of genetically identical, multicellular organisms called polyps. The polyps secrete skeletons of calcium carbonate that form the hard structure we recognize as large corals and coral reefs (and so often mistake for rocks). Corals are usually found at shallow depths in tropical waters, and depend on sunlight to survive. They feed on small organisms including plankton and tiny fish, and many corals are dependent on a specific type of algae which helps produce energy as well as assisting with calcification of the corals’ skeleton. Coral structures can grow in many different shapes, some resembling brains, cabbages, table tops, antlers, wire strands, or pillars.
Coral reefs, the large structures built out of millions and millions of coral skeletons over time, are extremely diverse ecosystems that are home to thousands of species. It is estimated that 25% of all marine species live in and around coral reefs, including over 4,000 species of fish, 700 types of coral, and thousands of other plant and animal species. The most common type of coral reef is called a fringing reef, found near coastlines of islands and continents, separated from the mainland by a small channel or lagoon. These are the types of coral reefs found in and around Cuba. Other types of coral reefs include barrier reefs, atolls, and patch reefs.
Cuba is home to large fringing coral reefs at Archipelago de los Colorados along the northwest coast, and the Jardines de la Reina in the south. These reefs are home to the largest fish populations in Cuba – possibly even in the entire Caribbean! However, these fish populations are consistently sought out by local, touring, and commercial fishermen, and overfishing is the main threat currently facing Cuba’s coral reefs. As a result, fishing is banned in the area, specifically a 386-square mile area surrounding the Jardines de la Reina, now set aside as a marine reserve area.
Coral reefs are extremely sensitive to environmental changes, and depend on clear, clean saltwater to survive. Pollution and agricultural runoff can have a huge impact on the health of a coral reef. In this sense, Cuba’s Communist government may have inadvertently helped protect the Cuban reefs for many years, by preventing the flow of fresh water to the sea as well as strictly limiting the availability and use of fertilizer and pesticides. However, as Cuba begins to open its doors to the rest of the world, increased commercialism and tourism is once again increasing levels of pollution, sedimentation, and development in coastal area, which creates a negative effect on the corals.
NARRATOR: Below the waves, powerful currents form a marine superhighway, where convoys of whale sharks patrol the coastline. Schools of dolphin and grouper follow the steady stream of nutrients, gathering to spawn and feed.
NARRATOR: For years, David’s focus has been on the foundation of this marine world… clusters of tiny creatures that are under attack across the globe: coral reefs. In parts of the Caribbean, more than two-thirds of the corals have died.
DAVID GUGGENHEIM: Coral reefs are considered the “rainforests” of the sea. And roughly 25% of the world’s corals have died in the last 25 to 50 years. And the estimates for the future are that half of the world’s corals will be gone within another 20 to 25 years.
NARRATOR: These undersea cities are besieged by a barrage of forces: pollution, rising ocean temperatures, overfishing and algae. But for ten years, David has been documenting an extraordinary phenomenon: Cuba’s corals are fighting back.
DAVID GUGGENHEIM: Corals are animals. Some of them look like plants. And here we have corals which have been wiped out, but we also have these young corals coming right back again. And that is very, very significant to see.
NARRATOR: Great gardens of healthy brain corals spread out across the sea floor. Vibrant sea fans and tube sponges show few signs of the coral die-off plaguing the rest of the planet.
DAVID GUGGENHEIM: It really is a profoundly emotional experience. You get in the water and it is like turning back time 50 years to what coral reefs looked like before human beings started messing with the way these ecosystems work.
NARRATOR: David believes Cuba’s defiantly resilient corals are tied directly to the history of the island, perhaps as far back as the collapse of the Soviet Union when fertilizers were no longer available.
DAVID GUGGENHEIM: Essentially, Cuba was forced to implement organic farming practices. And without all those nutrients flowing into the water, it’s very possible that that had the effect of lessening the impacts on coral reefs – less fertilizer, less algae growth.
NARRATOR: Then David spots an old friend, a species (spee-shees) he hasn’t seen in years… a spectacular stand of Acropora Palmata (ack-rah-pore-ah pal-mah-tah) – Elkhorn Coral.
NARRATOR: These breathtaking colonies of creatures are the most important reef-builders in the Caribbean. But they’re also one of the most sensitive. Nearly 95% of the world’s Elkhorn has been destroyed by pollution and disease.
NARRATOR: Here in Cuba’s waters, these could be some of the last of their kind on the planet.
DAVID GUGGENHEIM: Why are Cuba’s corals so healthy? We don’t know the answer. But, there’s a mystery we can unlock here that could provide lessons for us to conserve corals in many other places, including our backyard, 90 miles north of here.
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