Sharks

Humans have sailed the world’s oceans for thousands of years, but they haven’t all reached port. Researchers estimate that there are some three million shipwrecks worldwide, resting in shallow rivers and bays, coastal waters and the deep ocean. Many sank during catastrophes – some during storms or after running aground, others in battle or collisions with other vessels. Shipwrecks like the RMS Titanic, RMS Lusitania and USS Monitor conjure tales of human courage and sacrifice, sunken treasure and unsolved mysteries. But there’s another angle to their stories that doesn’t feature humans. I have studied the biology of shipwrecks in the United States and internationally for 14 years. From this work, I have learned that shipwrecks are not only cultural icons but can also be biological treasures that create habitat for diverse communities of underwater life. The USS Monitor, which sank off Cape Hatteras, North Carolina, in a...

PFAS, the “forever chemicals” that have been raising health concerns across the country, are not just a problem in drinking water. As these chemicals leach out of failing septic systems and landfills and wash off airport runways and farm fields, they can end up in streams that ultimately discharge into ocean ecosystems where fish, dolphins, manatees, sharks and other marine species live. We study the risks from these persistent pollutants in coastal environments as environmental analytical chemists at Florida International University’s Institute of the Environment. Because PFAS can enter the food chain and accumulate in marine plants and animals, including fish that humans eat, the spread of these chemicals has ecological and human health implications. Biscayne Bay and nearby coastal areas are teeming with fish, including many varieties that people eat. NPS image by Shaun Wolfe I...

“Shark!” When you hear this word, especially at the beach, it can conjure up images of bloodthirsty monsters. This summer, my colleagues and I are eager to help the public learn more about these misunderstood, ecologically important and highly threatened animals and their close relatives – rays and chimaeras. As a marine biologist focused on conserving sharks, I want people to know that an estimated one-third of them are at risk of extinction. Second, there’s an amazing variety of species in an astounding variety of shapes sizes and colors, and many of them get very little attention. Here is an introduction to a group of fishes that are at extremely high risk of extinction, and also delightfully weird: the rhino rays, named for their elongated noses. Scientists tag endangered sawfish off Florida’s west coast to identify and protect their habitats and educate the public about them. Motley shapes Rhino rays a...

Many sharks and rays are known to breach, leaping fully or partly out of the water. In a recent study, colleagues and I reviewed research on breaching and ranked the most commonly hypothesized functions for it. We found that removal of external parasites was the most frequently proposed explanation, followed by predators chasing their prey; predators concentrating or stunning their prey; males chasing females during courtship; and animals fleeing predators, such as a ray escaping from a hammerhead shark in shallow water. We found that the highest percentage of breaches, measured by the number of studies that described it, occurred in manta rays and devil rays, followed by basking sharks and then by eagle rays and cownose rays. However, many other species of sharks, as well as sawfishes and stingrays, also perform this behavior. A breaching white shark surprises researchers off Cape Cod, Massachusetts. Why it matters It takes a lot of ene...

The Discovery Channel’s annual Shark Week is the longest-running cable television series in history, filling screens with sharky content every summer since 1988. It causes one of the largest temporary increases in U.S. viewers’ attention to any science or conservation topic. It’s also the largest stage in marine biology, giving scientists who appear on it access to an audience of millions. Being featured by high-profile media outlets can help researchers attract attention and funding that can help super-charge their careers. Unfortunately, Shark Week is also a missed opportunity. As scientists and conservationists have long argued, it is a major source of misinformation and nonsense about sharks, the scientists who study them, and how people can help protect endangered species from extinction. I am a marine biologist who worked with five colleagues in 2022 to scientifically analyze the content of Shark Week episodes. We tracked down copies of 202 episodes, w...