Not on Exhibit
Saving Great White Sharks
The Monterey Bay Aquarium's Project White Shark, started in 2002, is helping research and exhibit great white sharks caught off the California coast. This project is promoting study, awareness and conservation of these magnificent animals.
Great White Sharks as Ambassadors
Six times—from 2004 to 2011—the Aquarium has exhibited young white sharks in our Open Sea exhibit. Seen by millions of visitors, these animals have helped us convey their powerful beauty, and educate visitors about the threats they face in the wild. After the first white shark in 2004 drew almost a million visitors, Executive Director Julie Packard called it "the most powerful emissary for ocean conservation in our history."
Three of the sharks stayed at the Aquarium for more than four months; one was on exhibit for two-plus months; and one remained with us for just 11 days. All were released healthy, and carried tracking tags that indicated they were doing well in the wild.
Our research involves:
- Great White Shark Exhibit Research and Development: We're developing ways to collect and exhibit white sharks in a safe and sustainable way. This includes collecting white sharks from the wild, transferring them, improving their standard of care while on exhibit and ensuring a successful release.
- Juvenile Great White Shark Research: Juvenile "young of the year" white sharks are found each summer in the Southern California Bight and as bycatch in the fisheries of Mexico and California. Yet we don't know where they're born, who the parents are, where breeding occurs or how they join adult populations. We're studying their movement, habitats, diet, population size and how they're affected by environmental toxins.
- Adult Great White Shark Research: We're learning how to protect adult white sharks from overfishing and the effects of bycatch by studying their movement, population size and foraging patterns.
- Great White Shark Genetics: To conserve white sharks, we need to know more about the movement between our coastal white sharks and those of Mexico, Australia, New Zealand and South Africa. Genetic (DNA) studies provide clues about population structure, parentage and the origins of white shark products found in global fish markets.
The Art and Science of Tagging
In most cases, before a shark is returned to the wild, we fit it with an externally attached, pop-up satellite tag with a tiny computer that collects and stores data on temperature, depth and light (used to estimate position). On a preprogrammed date, the tag pops off and floats to the surface. At the surface it transmits data to us via satellite. If the tag is recovered, even more data is retrieved. To date, scientists have tagged and tracked 18 juveniles and 167 adults.
Juvenile white shark tagging is coordinated by the Aquarium but partners include the Tuna Research and Conservation Center (TRCC), a collaboration between the Aquarium and Stanford University; the University of Hawaii; the Shark Lab at California State University, Long Beach; Chuck Winkler of the Southern California Marine Institute; and Dr. Oscar Sosa of Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE) in Mexico.
Despite popular perceptions of sharks as invincible, shark populations around the world are declining because of overfishing, habitat destruction and other human activities. Of the 350 or so species of sharks, 79 are imperiled, according to the International Union for the Conservation of Nature. Great white sharks are top predators in the sea but they're in grave danger of being depleted.
While over 100 nations fish for sharks, only a handful have enacted regulations to protect them. Most white shark research and conservation groups are located in places where the population of white sharks is highest—off California, South Africa and Australia. These regions, as well as U.S. waters off the East Coast and Gulf of Mexico, have laws that protect white sharks from either harassment or killing and the sale of body parts.
In October 2004, white sharks gained new protection in a global wildlife treaty approved by the U.N.-affiliated Convention on International Trade in Endangered Species (CITES). The 166 member countries in CITES approved regulations requiring a controlled system of permits for all international trade in white shark parts and products. Under the new regulations, trade is closely monitored, and may be banned altogether if white shark numbers keep fading.
Shark finning, the practice of cutting fins from a living shark and then tossing its body back into the ocean, is another threat. Millions of sharks worldwide are killed for fins each year. Fortunately, states and countries worldwide are banning this practice. In 2011, an Aquarium-sponsored bill passed with tremendous public support, banning the trade of shark fins in California.
Small in numbers, slow to reproduce and distributed throughout the world, white sharks are vulnerable to exploitation. Their relatively small numbers have been further reduced by fishing to feed the curio trade, by incidental catch in commercial fishing gear that targets other species and by sportfishing. Scientists hope that tagging and other research methods can unlock the mystery of the white shark and assist in global conservation efforts.
Great White Sharks on Exhibit
Exhibit of young great white sharks is one part of the Aquarium's Project White Shark, an effort by the Aquarium and its research colleagues to learn more about great white sharks in the wild as well as to inspire visitors to become advocates for shark conservation by bringing them face-to-face with sharks on exhibit.
Our White Sharks
The first white shark, a female, was in the Outer Bay exhibit for 198 days in 2004 before being released into Monterey Bay—the longest-ever exhibit of a white shark.
During her six-and-a-half-month stay, she was seen by nearly a million visitors and became, in the words of Aquarium Executive Director Julie Packard, "the most powerful emissary for ocean conservation in our history."
The five other great white sharks we've had on exhibit—three males and two females—were all returned to the wild. We displayed our second white shark for four-and-a-half months in 2006–07, a third animal for five-and-a-half months in 2007–08, a fourth shark for 11 days in 2008, a fifth shark for three months in 2009 and a sixth shark for 55 days in 2011. Most of our white sharks are collected in August in southern California waters with the help of a spotter plane and a commercial fishing crew using a purse seine net. Some have been collected inadvertently by commercial fishermen. The sharks remain in an ocean holding pen, sometimes for two weeks, until we confirm that they're feeding and swimming well before we transport them to the Aquarium and introduce them into our million-gallon Open Sea exhibit.
Many of our sharks have thrived on exhibit, gaining up to one foot in length and 100 pounds.
Two sharks were transported south and released near Santa Barbara, while four were released in Monterey Bay. "Decisions about where and when to release great white sharks are always governed by our concern for the health and well-being of the animals under our care," says Jon Hoech, director of husbandry for the Aquarium. These factors include how they feed, navigate the exhibit and their behavior toward other animals.
Tracking tag data indicate that released great white sharks have traveled distances of up to 2,000 miles, as far as the southern tip of Baja California, and to depths of 1,000 feet. Data from the tags confirms that five successfully returned to the wild and thrived for long periods. One died four months after release in a fisherman's net in Baja California, and one died soon after release from unknown causes.
About Great White Sharks
The great white shark (Carcharodon carcharias) is a legendary hunter. Dating back 50 million years or more, it's the world's largest predatory fish, and can reach 22 feet in length and weigh more than two tons. It's an apex predator—an animal at the top of the food web, with no natural predators other than humans.
Young white sharks are believed to eat fishes, rays and other sharks. Adults eat larger prey, including pinnipeds (sea lions and seals), fish, small-toothed whales, sea otters and sea turtles. They also eat carrion (dead animals that they have found floating in the water).
Because adult white sharks are highly migratory animals found in oceans around the world, little is known about their life history. They may live 20 years or more. They're able to sense minute amounts of blood in the water and the faint electrical fields given off by the bodies of potential prey species. They can swim at speeds up to 25 miles per hour in short bursts, and have been observed leaping out of the water in pursuit of prey. Females give birth to a litter of two to 14 live pups that are up to five feet long. The pups swim away from the mother immediately after birth; there is no maternal caregiving.
No Silverware Required
Scientists have determined that great white shark biting is not a haphazard series of chomps, but rather a predetermined progression. First, a white shark lifts its snout as much as 40 degrees and drops its lower jaw at the same time, opening its mouth to a suitable size for the food (left image). Then the shark protrudes its upper jaw from its snout, baring its gums in preparation to take a bite.
Together, these movements produce the startling image of a white shark bite: the raised upper jaw, sharp rows of teeth, exposed gums and connective tissue thrusting forward from the roof of its mouth.
Once the prey is in the shark's mouth, it lifts its lower jaw, trapping the prey so it can't escape. Finally, the shark retracts its upper jaw and lowers its snout, applying the force necessary to take a single bite of food.
The jaws of a white shark are filled with up to 300 very sharp teeth that can be three inches long and have serrations, like a saw. The narrow teeth on the bottom hold prey, and the triangular ones on top are for cutting.
Different types of sharks have teeth of different shapes. In general, the shape of a shark's tooth has to do with the type of food it eats and the way it hunts.
A shark has several rows of teeth in its mouth. Sharks bite with the outer row of teeth, but eventually these fall out. A tooth from the row behind moves up to take its place.
What is the Aquarium's Project White Shark?
It's a multi year study of great white sharks in the eastern Pacific Ocean that we began in 2002. The goals of the project include exhibit research and development, juvenile white shark research, adult white shark research and the study of white shark genetics. By tagging and exhibiting white sharks, we can contribute significantly to public understanding and protection of these maligned animals—an ecologically important and increasingly threatened species. By collaborating with several research partners, we've had success in these efforts.
What's different from other attempts to put great white sharks on exhibit?
Most past attempts by aquariums involved capturing a white shark and putting it directly on exhibit. Starting in 2002, we took a more cautious and methodical approach developed through collaboration with shark experts and aquarium colleagues from around the world. Our demonstrated success involved working with a white shark in an ocean pen before gradually proceeding, step-by-step, toward putting it on exhibit. If at any point in the process the shark had not done well, we would have tagged and released it back to the wild.
Why put a great white shark in an ocean pen first?
Our four-million-gallon ocean pen gives the shark a chance to recover from the stress of capture. Also, by working with the shark in the ocean pen, we can learn how well it maneuvers in an enclosed space—an important step in evaluating whether it would do well on exhibit at the Aquarium.
Why put a great white shark on exhibit at all?
Our mission is to inspire conservation of the oceans. We know that bringing people face-to-face with living marine animals is a powerful way to move them to care about the oceans and ocean life. White sharks are among the most maligned animals on Earth and one of many shark species worldwide threatened by human activities. In fact, white sharks are protected under the Convention on International Trade in Endangered Species (CITES). We believe there's no better way for us to raise awareness about the threats white sharks face than to let people see for themselves what magnificent and fascinating animals they are, tell the story of the threats they face in the wild and offer ways to take action that will protect them. Over two million people have seen the six white sharks we've exhibited.
Where do you keep the shark at the Aquarium?
White sharks are placed in our million-gallon Open Sea exhibit, where they join many other open-ocean species, including bluefin and yellowfin tunas, bonito, barracuda, sea turtles and other sharks. This exhibit was designed to simulate the open-ocean environment and engineered with sharks in mind.
How do you collect great white sharks?
Sometimes our husbandry staff attempts to collect young white sharks directly by hook-and-line or by purse-seining one or more sharks spotted from aircraft. We also rely on commercial fishing crews in southern California, who occasionally catch juvenile white sharks accidentally while fishing for other species. We have worked directly with a commercial fishing vessel to target young sharks, asking crews to contact us if they capture a young white shark that's alive and healthy. We have a rapid response team standing by to work with any sharks that are caught by commercial fishermen. Team members assess the sharks' health and either transfer them to the ocean holding pen or tag them and return them to the wild. There are many unknowns with sharks that are bycatch from a commercial fishery, including how long they've been in the net and to what degree their health has been compromised as a result. We have much more confidence that we're starting with a healthy animal when our team does the collecting.
How do you know if a shark is healthy and not suffering from stress?
An animal's feeding behavior is one of the best indicators of how it's feeling. If an animal is ill or stressed, it will typically stop eating. We watch carefully to see how often and how much a white shark eats, and can respond if there are any signs of problems. We also look for relaxed swimming patterns and calm tail beats. And we monitor its overall physical appearance.
What do you feed it on exhibit?
We've found that the young white sharks on exhibit feed enthusiastically on wild-caught salmon, mackerel, black cod, albacore and sardines, supplemented with specially formulated vitamins. Juvenile white sharks are fish eaters, only switching to marine mammals when they grow larger and have increased needs for an energy-rich diet from the mammals' blubber.
Will a great white shark eat other animals on exhibit?
Although these incidents are not unprecedented in the Aquarium, they are rare, and we try to keep them to a minimum—primarily by ensuring that the animals in our care are all well fed. While two white sharks we kept on exhibit bit two other sharks, others have showed no interest in their exhibit-mates.
What do you do if a shark gets too big for an exhibit?
We've successfully released sharks back to the wild when they outgrew their surroundings. When we've been able to tag and track these animals, we've found that they continue to thrive in the wild, despite their time on exhibit. Data from the archival tag retrieved from the white shark released to the wild in March 2005 showed that she survived and thrived after release. Also, after spending four years at the Aquarium, a sevengill shark swam several hundred miles back to its home waters and survived another two years before she was caught by a sportfisherman.
What will you do if it doesn't eat? Will you release it? Where?
If we find that a shark is not eating, but otherwise appears to be in good health, we'll return it to the wild. While the fourth shark was swimming well in the million-gallon Open Sea exhibit, it fed only one time during her stay, and the Aquarium's animal care staff decided it was best to return her to the ocean after 11 days. If a shark appears to be sick or injured and unlikely to survive a return to the wild, we will euthanize it humanely and perform a necropsy so we can learn as much as possible. Sharks are released offshore of the Monterey peninsula.
What about your tagging project? What do you hope to learn from tagging sharks?
Working with Stanford University scientists, through our collaboration in the Tuna Research and Conservation Center (TRCC), and with other research partners, we hope to learn more about the lives of white sharks in the wild. We want to learn where they go, what they do and how they fit into the ocean ecosystem.
What have you learned so far?
The juvenile white sharks we've tagged tended to remain in the coastal zone, although some traveled more extensively than others over the months we've tracked them. They traveled from southern California to halfway down the Baja peninsula in Mexico. While they spent most of their time in shallow waters, they also showed an ability to make 1,000-foot dives. Adult white sharks tagged off the coast of northern California have made long journeys into the eastern Pacific to a spot nicknamed the "Shark Café," and have ranged as far west as Hawaii. In future years, we'd like to learn whether their behavior changes from season to season, and what they're doing during their migrations.
How does this help great white sharks?
White sharks face many threats from human activity, especially commercial fishing and trophy hunting. Whatever we learn about their movement patterns can play a role in developing management strategies to protect them. By knowing what habitats white sharks use and the distances they roam, resource managers will have a better understanding of the risks white sharks face and will be able to conserve these rare animals more effectively.
How are great white sharks tagged?
We use a "pop-up satellite archival tag." Attached externally to a shark, it collects data—on temperature, depth and light (used to estimate position)—which it stores in a tiny computer. On a preprogrammed date, the tag pops off the shark and floats to the surface. When reaching the surface, the tag transmits the data to an earth-orbiting satellite, which sends the data to the laboratory. Some tags wash ashore, and their data are recovered when the tags are found and returned by beachcombers. We also use Smart Position or Temperature Transmitting (SPOT) tags that can provide near-real-time information about where the sharks go.
Are great white sharks threatened?
Yes, they're considered a threatened species. Their numbers are unknown but thought to be low. They're protected in many places where they live, including California, Australia and South Africa. They're slow-growing and late to reach sexual maturity, and they produce relatively few offspring. This makes them highly vulnerable to exploitation. They can be killed accidentally in fishing gear and are often targeted by trophy hunters. Because of trophy hunting, they're now protected under the Convention on International Trade in Endangered Species (CITES).