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Threats to Corals

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Cozumel is one of the largest cruise ship ports in the world, with 3 piers and up to 7 ships docking each day, and over 3.6 million tourists visiting each year. While these tourists have become vital to the economy, all this development is the largest threat to our coral reef ecosystem.


Cruise ships take on, and dump, ballast water from all over the Caribbean, spreading coral-killing diseases. Their giant propellers disturb local marine life, causing a steep decline in marine population along their routes. They also stir up sediment, which settles on the corals and block their photosynthesis, starving them to death.

Cruise ship threats

You can read about how local activists are fighting the construction of a 4th Pier

Cruise Ship companies have lobbied to build a fourth Pier along the edge of the UNESCO protected Marine Park and right next to the CCRRP’s coral garden. This massive 25 million dollar project proposes building an 800-yard long pier, which could bring up to another 11 cruise ships and 40,000 tourists to Cozumel every day. What’s left of our shallow reefs will be destroyed to build up to 50 new beach clubs along the island’s coast.

All the work we’ve done to save a slice of Cozumel’s coral reefs over nine years will be undone in a matter of months, and we’ll have to transplant CCRRP’s coral garden and laboratory – unless the construction is stopped.

Cruise ship protest

Islanders protest the approval of fourth dock for Cozumel

Sign the Petition against constructing a fourth dock on the island directly affecting the fundamental right of all Cozumeleños and Mexicans.

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Lack Of Water Treatment

Coral thrives in water with low nitrate levels, where very little algae can block the sunlight it needs for photosynthesis.


This is one of the reasons the water around coral reefs is so clear! When untreated sewage, which is high in nitrates, is dumped in the water by cruise ships or overflows from septic tanks, it upsets the ecosystem’s natural balance and causes algae blooms. These massive blooms can outgrow coral colonies at an alarming rate, covering a year’s worth of coral growth in a day, and starving the coral of the sunlight it needs to survive. 


We have to clean our coral garden daily to keep some algaes from overgrowing and smothering our corals.

Coral bleaching
Diving classes and conservation

New developments plan to dump wastewater directly onto Palancar reef, one of the most beautiful and diverse diving locations in the world - and they’re not the only ones - at least a dozen major hotels on Cozumel have been caught dumping untreated water directly into the ocean.

Cozumel’s wastewater disposal laws have not been updated in 25 years, and dumping untreated waste in the marine park is, unfortunately, legal.


There’s only one water treatment plant on Cozumel, and it only services the northern portion of the island. 

Human Damage

What can an individual do to

prevent damage?

There are small things we can all do to prevent further damage to the reef while visiting Cozumel.


Don’t wear sunscreen. Sunscreens, deodorants, and other beauty products contain non-biodegradable compounds that block UV light. It protects your skin, but if it washes into the ocean it attaches to corals, blocks the UV light they need for photosynthesis, and can kill them. Even products that are marketed as “reef friendly” still contain compounds that can be harmful.

Rashguards or UV protection shirts are a common solution in hot climates. These thin and quick drying shirts protect us from the sun without killing corals. They are readily available all over the island – buying one in Cozumel also helps the local economy.

Educate yourself on safe diving practices. While divers are often the some of the biggest supporters of conservation efforts, few of us are trained to be reef safe. New divers need to stay a safe distance from corals until they have mastered their buoyancy, so as not to hit or kick delicate corals.

Our Coral garden is set up near dive shops where new divers are trained, so we spend a lot of our time rescuing coral that has been kicked and broken by inexperienced divers. Many experienced divers know a lot about fish, but very little about the coral reefs that protect them.  

Learning to properly interact and protect coral allows you to enjoy diving with the knowledge that you are not harming the beautiful environment you came to Cozumel to explore. You can find information on our courses below

planting coral

Use your voice. Hands down, the biggest threat to both the reef and the CCRRP is the building of a fourth cruise ship pier in Cozumel. It will be apocalyptic. The cruel irony is that it’ll also destroy the island’s economy in the long term. People come here to dive and snorkel and see the beautiful reef, which is being killed by irresponsible development. When the reef is dead, they’ll stop coming.

PADI Research Diver
Diver in Mexico

Activists on Cozumel and abroad have organized protests to raise awareness around this issue. One way you can help from abroad is to use your voice to amplify their work, and by signing the petition against the new pier.


Diseases threaten corals like every other organism.

coral diseases

When a coral polyp is sick, it expels its symbiotic algae – the organism that allows it to photosynthesize – and loses its brilliant color. This is called coral bleaching. If the corals recover quickly, they can get their algae back and survive. But if conditions are too stressful for too long, the corals die.


Bleached, or “dead” portions of reefs are becoming more common as human activities, algae blooms, rising water temperatures, and pollution increasingly stress the corals immune systems, making them significantly more susceptible to disease.

There are two major diseases threatening Cozumel’s coral right now: Stony Coral Tissue Loss Disease, which manifests as rapidly expanding lesions on coral colonies, and White Band Disease, in which tissue peels off from colonies leaving behind a “white band” of exposed calcium carbonate skeleton.

Stony coral tissue loss disease (SCTLD) is one of the biggest threats to corals in Cozumel

Stony coral tissue loss disease (SCTLD) reached Cozumel in 2018, carried by cruise ships from one port to another. In just a year over 60% of Cozumel's corals died. Some coral species went entirely extinct in the wild.

The CCRRP found that covering coral in an antibiotic paste has a 50/50 chance of stopping the disease from spreading to adjacent corals, but there is no definitive cure to date.  To prepare for the worst, we are growing pillar corals and other at risk species in our aquarium and garden. This will help keep those species alive until either the surviving population of corals gain immunity or a better treatment is found.

Threats to Coral
Divers planting coral reefs

White Band Disease came from Florida to the Caribbean in the 1980s. Unlike SCTLD, white band disease largely targets Elkhorn and Staghorn corals, two of the most common foundation species on the reef. With a 95% mortality rate, white band disease literally destroys the reef’s foundation. 

Warming water conditions and exposure to untreated wastewater are the main contributors to outbreaks of white band disease. We are still looking to find an effective and distributable cure.

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