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Caribbean Marine Life & Ecosystems

Preserving Our Precious Caribbean Coral Reefs

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The Caribbean Ecosystem

The Caribbean is a vast and complex marine ecosystem upon which millions of people depend, whether they call the famous sea home or enjoy its bounty elsewhere. It is home to one of the world’s 36 biodiversity hotspots, which encompasses the bulk of the region’s islands. 

Underpinning this incredible breadth of marine life are several keystone species—species that have a disproportionately large effect on the rest of their communities. In the Caribbean, keystone sea animals include apex predators like sharks, as well as smaller species like starfish, parrotfish, and major coral species such as the elkhorn. 

Marine biologists look to these species for clues and insight into the overall health of the ecosystem. Unfortunately, the Caribbean’s keystone species have been in trouble since at least the 1980s, when the black urchin went extinct and a disease outbreak decimated elkhorn coral populations. Sharks, meanwhile, have been overfished for decades and are noticeably scarcer, while starfish are prone to massive die-offs due to excessive ocean warming.

Caribbean Marine Life Conservation

Corals Under the Sea

Helping scientists and conservationists maintain healthy populations of keystone sea animals in the Caribbean is one of the goals of Alpha Submarine Adventures, but providing that aid takes an enormous amount of resources. You can be a part of our ecological mission by donating to Alpha today! Your money will go directly toward the funding of our submarine eco-tours, which simultaneously increase public awareness about coral reefs and collect vital data to help marine researchers. Become a part of Alpha’s mission today!

Below is a breakdown of some of these keystone species and other important organisms within the Caribbean ecosystem:

Pink Earth


A variety of sharks are drawn to the Caribbean’s many reefs and lagoons, primarily for the abundance of prey. Common species include the Caribbean reef shark, which grows to between 6 and 8 feet, as well as the easily identifiable blacktip reef sharks. As apex predators, reef sharks (and other shark species) are incredibly important to coral reefs because they keep other populations in check.


Tiger sharks are the largest shark species found in the Caribbean, growing to lengths in excess of 16 feet. They prefer sea turtles but will eat nearly anything, including other sharks. Bottom-dwelling nurse sharks, which feed on crustaceans along the seafloor, are also commonly spotted in Caribbean waters. Hammerheads, as well as the large and aggressive bull shark, also call the Caribbean home.

Diver int he Reef


Starfish play their own important role in Caribbean reefs, as they help control populations of mussels, snails, and other seafloor denizens, and are in turn preyed upon by birds and sea otters. One of the more common species of starfish in the Caribbean is the cushion starfish, an ample-bodied sea star whose color ranges from white to tan to pink and even bright red.

Pink Earth


Parrotfish are brightly colored reef-dwellers that eat the algae off coral, making space for new coral growth. This function is essential to reef growth and overall health, as algae will overtake coral and dominate reefs if not controlled. Currently, overfishing of parrotfish threatens to reduce their rate of essential algae-munching; Alpha Submarine Adventures hopes that introducing tourists to the roles of Parrotfish and other keystone species will inspire more conscientious consumer choices and galvanize support for reef protection.

Image by Francesco Ungaro
Image by Francesco Ungaro

Major Coral Species

Over the past 5,000 years, elkhorn coral—as well as its closely related cousin, the staghorn coral—played a major role in reef-building, both in the Caribbean and other parts of the world. These coral species’ ability to have broken pieces reattach themselves to the reef and start growing again allowed them to create vast reef kingdoms. Unfortunately, an array of threats to elkhorn coral have surfaced in the past hundred years or so, including a disease outbreak in the 1980s, pollution due to intensifying world economic activity, and ocean acidification due to warming temperatures. 


Help protect the Caribbean’s keystone species today with a donation to Alpha Submarine Adventures!

Learn More About Our Mission And Donate To the Cause

Ready to learn more about how you can invest in our submarine adventures, and how we’re working to protect our coral reefs in the Virgin Islands? Eager to get started right away? Make a donation here!

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