Along a shoreline in northwest Africa, scientists made a gruesome discovery: the carcasses of 230 dolphins, a pilot whale, and 15 endangered sea turtles. These animals were probably killed as "bycatch"—unwanted creatures accidentally hauled aboard fishing vessels. Bycatch totals at least 30 million tons of sea life each year.

Nuclear weapons, Agent Orange, and mustard gas have helped to safeguard one thriving Pacific coral reef ecosystem. But what effect have they had on the area's marine environment? Sharks are helping researchers to find out.

At the National Aquarium in Baltimore, researchers are working with a pair of 4-foot-long nurse sharks to investigate how the creature's immune system responds to the anthrax bacterium. The approach may serve as a template for developing other tools to detect other bio-weapons.

Charles Maxwell is an underwater cinematographer based in Cape Town, South Africa. A keen diver and lover of the marine environment for 35 years, Maxwell has made documentaries for the National Geographic Society and the BBC. He talks about his life's work and shares some of his favorite underwater images. Two shark photo galleries included:

It's almost summer and war-weary, economy-embattled Americans will head seaside in their millions. With so much frolicking in the surf there will be a few nips from sharks, experts warn—although bites are statistically extremely unlikely and almost never fatal. Swimming with sharks is not as dangerous as driving to the beach.

Scientists studying trade statistics from Hong Kong's bustling dried seafood markets have found that the global shark fin trade may have been significantly underestimated. The study intensifies conservationists' concerns for sharks and other threatened marine species.

A new study finds that sharks in the North Atlantic Ocean are vanishing at a phenomenal rate. Hammerhead shark populations shrank the most, dropping 89 percent in the last 15 years. Researchers say the only way to stop this shark slide may be to limit fishing.

This is the last article of a three-part series tracking the adventures of Jeff Carrier and Harold "Wes" Pratt as they continue their long-term study of shark breeding. The two shark specialists have studied nurse shark breeding and behavior at a remote Florida Keys nursery for 12 years. This year, a National Geographic scientist is participating in the study, attaching Crittercams to some of the sharks, allowing us to see the world from a shark's point of view.

Roaming Earth's tropical and subtropical waters, hammerhead sharks school in large groups around underwater mountains. Are they using the seamounts as "stepping stones" for migration? The answer could ultimately help marine conservation efforts.

A female white spotted bamboo shark at the Belle Isle Aquarium in Detroit surprised zookeepers in July by giving birth to two babies. Why the surprise? It was a virgin birth: She hadn't been near a male for six years.

A photograph circulating on the Internet showing a shark attacking a helicopter is hoax—and it's not National Geographic's "Photo of the Year" either. Story includes photo gallery.

Coming face to face with great white sharks—"Jaws"—is dangerous work, but necessary to attach satellite and acoustic tags to the animals, which will help scientists document their movement and better understand the behavior of this legendary predator.

A burgeoning appetite for shark-fin soup has prompted the development of new genetic tests that will help safeguard the shark for commerce as well as conservation. This story airs on our U.S. cable television program National Geographic Today.

This article is the second in a series on Jeff Carrier and Harold "Wes" Pratt's ongoing study of shark breeding. The two shark specialists have studied nurse shark breeding and behavior at a remote Florida Keys nursery for 12 years. This year, a National Geographic scientist is participating in the study, attaching Crittercams to some of the sharks, allowing us to see the world from a shark's point of view.

Each year since 1991, shark specialists Jeff Carrier of Albion College (Michigan) and Harold "Wes" Pratt of NOAA's National Marine Fisheries Service have returned to the remote islands of the Florida Keys to study the mating habits of nurse sharks. The sharks return each year to an ancient shallow-water breeding ground, which affords a unique opportunity to study their behavior in the wild. This year, National Geographic is along for the ride, and contributing its Crittercam technology to the scientific expedition.