The Last Unicorns

The pillar coral is as unique in its taxonomy as it is in its growth form. It is also poorly studied — and it is in decline. Efforts have ramped up to study and conserve this species.

A female diver inspects some coral

Differentiating Coral Bleaching and Coral Mortality

Corals bleach, or turn white, when their symbiotic algae are expelled from the corals’ tissues due to stressors such as excessively warm water. Bleached corals can and do recover when favorable conditions resume.

A stark white coral is nestled in a bed of other corals

Blame the Ballast

MARITIME TRANSPORT HAS MORE TO DO WITH CORAL DISEASE than you might think. Just like most animals, corals can get diseases. Researchers first recognized coral disease in the early 1970s. […]

coral disease from ballast water, connection between coral disease and maritime transport, ships, ballast, coral disease, coral bleaching, human influences on coral disease, microscopic organisms called ciliates, ballast water exchange (BWE) ballast water management, control your dive buoyancy to protect coral, decontaminate dive gear to protect coral, Alert Diver magazine Q4 2023

The Most Important Fish in the Sea

Menhaden, also known as bunker, are forage fish that play a critical role in the ocean food web. They are a vital source of food for wildlife up and down North America’s Atlantic seaboard. But their population management ignores the importance of the food web. Learn more and what you can do.

Four fishermen grasping net of menhaden

Clipperton: A Plastic Paradise

A little dot in the Pacific, Clipperton is surrounded by coral reefs and encloses a stagnant lagoon. Despite looking like paradise, Clipperton is being invaded by plastic.

Several divers wrangle a discarded net with the goal of removing it from the ocean

Turning the Tide of Mangrove Loss

Mangroves live along subtropical and tropical coastlines. Their upper trunk, branches and leaves grow above the waterline, but an extensive network of roots remain mostly underwater. Dense patches or forests of mangroves are habitats for terrestrial, estuarine and marine species that include invertebrates, fish and many types of seabirds and waterfowl, and they provide shelter as well as feeding and breeding space for 174 marine megafauna species. Mangrove forests provide also protect coastlines against erosion and flooding and help mitigate climate change.

Mangroves near a river mouth along the Belize coast

A Perfect Storm of Warm

Thanks to warming ocean temperatures, animal encounters have changed and increased. Read about the unique sea creatures divers are interacting with.

Magnificent hammerhead shark says hello to photographer

Sympathy for the Devil

Manta rays are often forgotten in conservation and research efforts. Several species of rays are under threat. Learn more about manta rays and what you can do.

A black-and-white image of a devil ray swimming close to the ocean surface

Continuing a Tradition of Ocean Stewardship

After helping to establish the world’s first shark sanctuary in his nation’s waters in 2009, President Tommy Remengesau Jr. of the Republic of Palau signed legislation last year that set aside 80 percent of his small west Pacific island nation’s ocean as a fully protected marine sanctuary.

Arial view of Palau's Rock Islands

End the U.S. Shark-Fin Trade

Divers should take a stand to end the shark-fin trade. A bipartisan bill before Congress is poised to stop the sale of shark fins in the U.S.