Tag: sharks

Sharks And Stingrays Close To Extinction, According To New Study

Posted on by Morgan Riley

Sharks have been fascinating sea creatures for as long as we can remember. Are they as life-threatening as it’s depicted in Jaws? But unfortunately, sharks are not threatening our lives; they are endangered themselves. A new report reveals many of the world’s most unique sharks and rays are close to extinction. This includes the largetooth sawfish, whale sharks, electric rays, and more. These sea creatures have swum the oceans for over 250 million years.

But now, they’ll soon disappear into extinction— forever.

More At Risk

According to the new report, sharks, rays, and chimeras are among many animals on the Evolutionarily Distinct and Globally Endangered (EDGE) species. Many of these sharks and rays are at the top of their food chain, making them crucial to the health of the Earth’s ecosystem. If they were to go extinct, it would harm the entire aquatic environment.

EDGE Sharks coordinator Fran Cabada said, “Sharks, rays, and chimeras have been around since the age of the dinosaurs, but due to human activities, their modern relatives are facing threats all over the world.”

But now that conservationists know these animals are on the endangered species list, they can implement efforts to protect these sea creatures from complete extinction. Who would want to say goodbye to these beautiful sea animals?

The Largetooth Sawfish

The most critically endangered shark is the popular largetooth sawfish. Usually found in tropical waters, the shark is famous for its unique shape. Unfortunately, the sawfish population has declined rapidly in recent years, largely due to unsustainable fishing.

Everyone can agree the shark is unique, but it’s now the highest-ranked EDGE species in the world. That’s not something to celebrate.

The Basking Shark

Not that many people know about this unique shark, but the basking shark is a generally harmless shark. As a slow-moving sea creature, it feeds in shallow waters.

Much like the largetooth sawfish, the basking shark population is decreasing because of the fishing industry. The shark’s fins are found in soup and its cartilage is used in traditional Chinese medicine.

The Whale Shark

The largest living fish species, the whale shark can live up to 100 years old. But now, they’re at high risk of endangerment. Because of their impressive size, growing up to 40 feet, the sharks are targeted by fishermen.

Conservationists have worked hard to protect these sea creatures. Their hunting is now banned in the Philippines, India, and Taiwan.

Sting Rays

While sharks are endangered species, we can’t neglect rays, who dominate the EDGE species list. This includes stingrays, eagle rays, and guitarfishes. At the moment, conservation action for rays is lagging far behind protection for endangered sharks.

Overfishing is the main threat to the species. Rays have been decreasing in the ocean system for the past 30 years. Unfortunately, if they, along with sharks, were to become extinct, it would harm the Earth’s ecosystem in more ways than what many realize.

“The modern extinction of a single species from this list would cause the loss of millions of years of evolutionary history,” said Matthew Gollock of the Zoological Society of London.

MORE: World populations of marine wildlife have declined by 50% over the past four decades. Which species are most in danger and what can be done to protect them?

A 512 Year-Old Shark Is The Oldest Living Vertebrate On The Planet

Posted on by Morgan Riley

Greenland sharks are among some of the longest-lived vertebrates on the planet, with lifespans ranging from 300 to 500 years. Scientists studying these sharks in their native waters of the North Atlantic Ocean have recently found a specimen who is estimated to be 512 years-old. By comparison, the oldest known Galapagos Tortoise, a species often referred to for their longevity, lived to be only 152 years old.

The Key To A Long Life

What makes these giants live such long lives? Part of their longevity is believed to come from their slow metabolisms. Larger animals, like whales and elephants, tend to have longer lifespans due to slower metabolisms. Smaller animals, such as parrots, also tend to live longer, leading us to conclude that size isn’t all that matters.

For Greenland sharks, their habitat has a significant effect on their metabolisms. The icy waters of the North Atlantic mean lower body temperatures and a need for more efficient energy use. As a result, their bodies age more slowly, extending their lifespans.

Late Bloomers

A side-effect of their long lifespans is their lengthy growth cycle. Greenland sharks don’t reach adulthood until they are 100 years old, which means that they cannot produce offspring until they have survived for at least a century.

The sharks grow 0.4 inches per year up to their full-grown length of 21 to 24 feet. As fully-matured adults, Greenland sharks weigh in at anywhere from 2,200 to 3,100 pounds. On average, scientists have observed these giants to be between 8 and 15 feet long and about 880 pounds.

A Bizarre Delicacy

One of the Greenland shark’s adaptations for survival makes their meat inedible without the right processing. Their bodies contain high concentrations of trimethylamine oxide and urea. The former is what makes it toxic, and the latter gives it an unpleasant, urine-like odor. When consumed in small amounts, trimethylamine oxide produces effects similar to extreme drunkenness. Dogs that have eaten unprocessed shark meat are unable to stand or walk until their bodies process the toxin.

As a precaution, when humans prepare the flesh, they often bury it in the ground for anywhere from six to eight weeks to press out the chemical before digging it up and hanging it to dry for several more months. Even then, the smell of urea persists, and that odor has given rise to many origin stories and legends in local folklore.

A Species Steeped In Legend

According to an Inuit creation story, a woman washed her hair in urine and dried it with a cloth that blew into the ocean to create Skalugsuak, the first Greenland shark. A different story from the same culture says that different sea creatures were created from the severed fingers of a drowned girl, one of which was Skalugsuak. The Igloolik Inuit believe Greenland shark flesh to be an aid to their shamans. In their cosmology, the Greenland shark lives in the urine pot of their goddess of the sea, Sedna, and that is why its flesh smells so strongly.

NOAA

While its place in legend has been set for centuries, as it doubtless will for centuries, the Greenland shark’s mark in the history books is freshly made. Outlived only by immortal jellyfish, the ancient sharks continue to awe and intrigue marine biologists and geneticists alike as we search for the keys to human longevity.

MORE: These microbes at the bottom of the sea teeter on the edge of life and death, and can live for thousands, maybe even millions of years with almost no energy.

Scientists Follow As The Pacific’s Great White Sharks Disappear To A Hidden Lair

Posted on by Matthew Rusnic

Ocean researchers recently solved a great mystery about some of the world’s most feared and fascinating animals. Great white sharks star in Hollywood movies, get in-depth Discovery Channel coverage for an entire week each year and haunt beaches and vacations all summer long. And even though these great fish of the sea have existed since the time of the dinosaurs, there is still much that we don’t understand about the great white shark.

Where Do Great Whites Go For The Winter?

One thing we didn’t know about the great whites that frequent California in the summer was where they go once winter rolls around. Some scientists figured out how to lo-jack some great whites and followed them to what looked like a vast void in the middle of the Pacific. This migration spot puzzled researchers who saw it as a dead zone. Great white sharks like to eat seals. That is why they show up at popular swimming areas along the California coast and vacation spots on the Atlantic, such as Cape Cod in Massachusetts.

Seals are mammals, but unlike whales—the largest sea air-breathers—they like to be near land. Out in the middle of the sea, there are no seals. This fact led to much speculation about the shark’s destination. But when ocean scientists looked at this vast 160-mile radius area between California and Hawaii, they noticed it was actually chock-full of tasty tidbits.

Welcome to “White Shark Cafe”

Rather than a cold and empty void, this region has a rich mid-water area that is well-stocked with squid and small fish. The sharks weren’t swimming away to some spot to rest up for the winter, they were going to a veritable smorgasbord.

So, how did the scientists pinpoint where these sharks fled? Through advances in technology, researchers were able to tag certain sharks during their summer frolicking. These pinger tags emit a radio-frequency-signal that allowed the researchers to follow their every move. In addition, the tags also were programmed to detach and float to the surface when the sharks reached their winter feeding spot.

The Cafe Is Wide And Deep

And while the feeding grounds are known to cover a surface region of the Pacific that is roughly the size of Colorado, the surfae area is nothing compared to its volume. Once tagged and monitored, scientists learned that the great sharks were diving deeper than ever thought possible. Here the great white’s food runs reached depths of up to 3,000 feet. These depths are cold and inhospitable to the sharks, but sometimes a warm current flows to these depths. When this happens, schools of squid and fish dive, and the sharks follow.

The sharks follow a diving pattern. During the day, sunlight allows them to dive deep, while at night, they restrain themselves to a shallow dive. The researchers also noted that as summer approaches, male and female sharks approach hunting differently. The males begin rapid repeated diving—up to 140 times a day—while the females continue a night/day pattern.

The reason for this gender difference is now a new mystery for the scientists to ponder.