Showing posts tagged as "sharks"
How do you FIN-gerprint a Great White Shark?
To the untrained eye, one shark fin cutting through the water probably looks like any other. Yet each great white shark dorsal fin gives our researchers and their colleagues important clues that will help to identify and protect them.
Like the swirls on a human fingerprint, the shape and notches of each white shark’s dorsal fin are unique, enabling scientists to catalog and track sharks across the oceans.
Building a Fin Photo Database
Since 1987, great white shark researchers at the aquarium, Stanford University, Point Blue, Montana State University and the University of California, Davis, have been photographing dorsal fins – first in waters off the Farallon Islands, and later at Año Nuevo Island and Tomales Point. They’ve created a photo database identifying 270 individuals over the past quarter century, providing the basis for the first-ever population estimate of adult and adolescent white sharks off the Central California coast.
This database helps scientists better understand where white sharks go and whether they return to the same waters on a regular basis. Fin IDs also help them estimate the number white sharks at these locations, and monitor the survival of individual animals.
Scientists have found that just as humans routinely travel between important locations — home, school, work — so too do great white sharks. White sharks congregate seasonally at spots along a migration route that takes them from the Central California coast, to the middle of the Pacific, and past southern California and Mexico.
Scientists use seal-shaped decoys to entice white sharks to the surface where it’s easy to photograph their fins. They also gather information such as size and sex when the sharks swim alongside their research boats. By comparing fin photos of the same sharks over the years, researchers concluded that – just as with our fingerprints, which remain the same over a lifetime – the overall shape of a shark fin remains fairly constant (with the exception of scrapes and scars).
In 2013, of the 80 individual adult white sharks photographed by researchers from the Aquarium and other institutions, nearly 65 percent had been seen in previous years. This suggests that the team is getting close to recognizing most of the adult great white sharks that frequent Central California waters.
Several have been coming back to the same waters for more than 20 years. One, a 16-foot male known as “Tom Johnson,” has been sighted for the last 26 years - the longest tracking period for any white shark on earth.
On the seventh day of the ocean, my true love gave to me… 7 Sharks-a-Swimming!
Love sharks? Join us just before we open our doors to the public and discover over a dozen species of sharks, skates and rays that call the Aquarium home.
Ever wonder about our largest hammerhead shark? She’s more than 11 years old and weighs 150 pounds!
A days-old baby swell shark is on exhibit in our Kelp Forest. The green-eyed shark is just one of many baby swells that regularly hatch inside the bustling exhibit.
It’s a lucky visitor that gets to see a baby or even an adult; they’re a big hit when they appear during the feeding show. This small (up to three feet), harmless and well-camouflaged shark prefers to hide in rocky crevices during the day, and feeds at night.
We often move young swells from the Kelp Forest to the small exhibits at the nearby touch pool, allowing visitors to get a close look at these beautiful sharks. As they grow, we move some to other exhibits, until they may eventually wind up back in the Kelp Forest exhibit.
We might trade adult swells with other aquariums in return for other species. Some we release into Monterey Bay via a detour into the outdoor Great Tide Pool, where they delight young kids participating in our Underwater Explorers summer program.
The swell shark is named for its unique defense posture. If threatened, it curls into a sharp U-shape, grasps its tail (caudal fin) in its mouth and swallows a large quantity of sea water, swelling to twice its normal size. This behavior makes it difficult for a predator to bite or evict a swell shark from its hiding spot.
Love sharks? We just added a 6-foot, 71-pound sevengill shark to our Monterey Bay Habitats exhibit, collected from San Francisco Bay. Besides being beautiful to look at, these sharks are part of ongoing research designed to help save sharks.
Fifteen-foot white shark bites robot? Now that’s a battle of the titans! An underwater research robot from the Monterey Bay Aquarium Research Institute recently came back with shark teeth embedded in its aluminum hull.
This underwater robot, known as Tethys, just came back from two continuous weeks at sea, helping MBARI scientists monitor harmful algal blooms as part of the Fall 2013 CANON experiment. When MBARI engineers pulled the long-range autonomous underwater vehicle (LR-AUV) from the water they discovered large scrapes on its sides. Based on the gape of the bite mark, shark expert Dave Ebert from Moss Landing Marine Laboratories estimates that it was a 15-foot-long white shark that attacked the AUV!
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Love sharks? We just added two beautiful male sevengills to our Monterey Bay Habitats exhibit, collected in San Francisco Bay. One is seven feet and 84 pounds; the other is six feet and 53 pounds. These sharks are tagged and will eventually be released as part of our efforts to learn more about sharks, which are threatened worldwide.
Did you know that today is Endangered Species Day, celebrating the 40th anniversary of the federal Endangered Species Act? We rescue, study and care for many endangered species at the Aquarium, in cooperation with government agencies. These include snowy plovers, sharks, sea otters, penguins, rockfish and albatross. How will you celebrate this special day?
We’re always happy to report that an exhibit animal thrived and was then successfully released. That’s the case with “Dottie,” our largest female sevengill. She gained 15 pounds since first going on exhibit in July 2012!