Swarms of up to over a thousand basking sharks have been spotted along the northeastern U.S., puzzling experts who study the normally solitary species.
Aerial surveys meant to locate endangered North Atlantic right whales in recent decades have revealed massive groups of the world’s second-largest fish. Found worldwide, these slow-moving filter feeders pose no threat to humans.
As big as basking sharks are—at 32 feet long outsized only by the whale shark—the deep-sea dwellers can be tricky to track down.
And without those opportunistic sightings, “that data was hiding away,” says Leah Crowe, leader of a recent study on the phenomenon and a field biologist at the National Oceanic and Atmospheric Administration’s Northeast Fisheries Science Center. “Our goal is not to do that with our research.” (Read about a huge basking shark caught off Australia.)
In the study, published in the Journal of Fish Biology, Crowe and colleagues documented 10 sightings of large groups of basking sharks between 1980 and 2013 along the coast of Nova Scotia to Long Island.
The researchers uncovered about 10,000 documented sightings of basking sharks in the database, and 99 percent were of groups of seven or less.
Basking sharks may look ominous, but their open mouth serves to filter zooplankton and other small creatures through their gill rakers. PHOTOGRAPH BY NICK CALOYIANIS, NATIONAL GEOGRAPHIC CREATIVE
This is concerning…
Great Britain and Ireland can be a little chilly, but they’re surprisingly balmy for their latitude. These regions have an ocean current to thank for that warm(ish) weather. Known as the Atlantic Meridional Overturning Circulation (AMOC), the current works like a conveyor belt, drawing warm water up from the Gulf Stream to North America’s east coast and then shunting it toward Europe.
But, as Victoria Gill at the BBC reports, two new studies suggest that the AMOC is the weakest it’s been in over 1,600 years, with the most drastic changes taking place in the last 150 years.
The first study, published in the journal Nature, addresses the history of the AMOC. Researchers studied the size of the grains in cores of sediment from the ocean floor. As Andrea Thompson at Scientific American reports, the stronger a current is, the larger the grains of sediment it can move, allowing researchers to map changes in current strength by sediment size. The team also looked for tiny fossil critters, known as foraminifera of “forams,” to get a sense of ocean temperatures. Since some species of foram thrive in warm waters while others prefer cooler temps, researchers can use foram species as a rough thermometer for past ocean temperature.
In the second study in Nature, the team used state-of-the-art climate models and a century of ocean sea surface temperatures to study AMOC changes. The results of both studies suggest that the AMOC is weak, but when that change started is up for debate.
In 1996, UNESCO designated the Belize Barrier Reef Reserve System a World Heritage Site, with the former British colony responsible for protection. It’s a mandate that the country has at times struggled with. By 2009, the site was on UNESCO’s “danger” list, with the organization saying that the country needed to enact better management and safeguards. But since that low point, Belize has worked to turn things around. And ocean conservation observers say there has been impressive progress. Hence the helicopter flight, which was a victory lap of sorts.
Just this December, Belize became the first country in the world to put a moratorium on all offshore oil exploration and drilling. Oceana had arranged the helicopter to help give politicians a sense of what they had protected, and what still needs to be done. “I’m really looking forward to getting off the endangered list,” Chanona said.
A black grouper patrols a coral garden in Belize. The country is taking new steps to protect this fragile resource for the future. PHOTOGRAPH BY BRIAN J. SKERRY, NATIONAL GEOGRAPHIC CREATIVE
How Culture Guides Belugas’ Annual Odysseys Across the Arctic:
The study on beluga culture joins an emerging
line of research which has so far focused on orcas and sperm whales, and
expands the common understanding of what constitutes “culture” beyond
the realm of humans and other primates.
If you were a red coral, you’d have enough time to fulfill several bucket lists before you died. Though it’s hard to figure out what you’d put on them.
The red coral, which can live for five hundred years, is one of several marine species that make human lifespans look like a blink of the eye by comparison. In a new study, scientists have honed in on what enables some of these marine species to live for hundreds of years.
The stability of the deep sea environment likely helps deep-dwelling species live longer.
Staying put has its merits as well.
“Being sessile seems to correlate with at least the potential for longevity in marine animals as well as terrestrial plants,” Doak says.
Another factor, Monterro-Serra notes, is that these sessile species are clonal. They “form a colony of multiple units that are genetically identical, called polyps in the case of corals and gorgonians.”