Why no aquarium has a great white shark
There are some shark species that seem to
do okay in aquariums. You’ll see a lot of nurse sharks, zebra sharks, some reef sharks
and sand tiger sharks. But not the great white. For decades, aquariums have tried to contain
the world’s largest predatory fish. Institutions like Marineland, SeaWorld and
the Steinhart Aquarium repeatedly took in white sharks during the 1970s, 80s and 90s, at times
drawing huge crowds. But they never lasted long. Some needed help swimming. None of them would eat. The longest one lasted was just 16 days. A 1984 report by the Steinhart Aquarium put it this way: “In most cases it could be said that all these
captive sharks were merely in the process of dying, with some taking longer than others.”
They had constructed an elaborate transport tank with a harness and IV fluids, but still
couldn’t keep the sharks alive. It wasn’t until 2004 that the Monterey Bay
Aquarium proved that it was possible to keep white sharks for at least six months. It took
a massive effort, and no one’s done it since. JON HOECH: Our approach was one of sort of
a systematic, logical sequence of things leading up to our success and it started with designing
a tank. The Monterey Bay Aquarium had a million gallon,
egg-shaped tank, 35 feet deep, designed for open-ocean animals like tuna and sharks. So
you need a big tank. You also need a small shark. Adult great whites reach 15 feet on average. The Monterey Bay Aquarium nabbed one in 2004
that was 4 feet, 4 inches, less than a year old. That made it easier to move and easier
to keep. JON HOECH: When they’re young they feed
on fish. And as they get older they transition to feeding more on mammals. And so we were targeting
the age bracket where we knew we were more able to feed their natural diet.
And once they collected the shark, they didn’t take it straight to the aquarium. Instead,
the Monterey Bay team set up a 4 million gallon pen right there in the ocean.
That way they could monitor the shark and see if it would feed before they moved it
into a transport tank to travel from southern California where the sharks were born up to the aquarium.
Sharks, like all fish, need to have water continually passing through their gills in
order to get oxygen. Most species can open and close their mouths
to pump the water through. But white sharks and a couple dozen other species don’t do
that. To breathe, they have to move forward through the water with their mouths open.
That’s why white sharks start to weaken as soon as they’re caught in a net. And
that’s why they needed a custom built transport tank with mobile life support.
JON HOECH: Everything from oxygen sensors and video cameras and lighting and filtration
systems that were needed for what turned out to roughly be 9 to 11 hour transport time. Aquarium attendance jumped 30 percent while the shark was on display. After 6 and a half months, they decided to release it because it had killed 2 other
sharks. Over the next 6 years, the aquarium displayed
5 more baby white sharks – some they paid fishermen to hand over, some they caught themselves.
Their stays ranged from just 11 days up to 5 months. The Monterey Bay Aquarium had succeeded
in doing what no one else could. But it did take a toll on the sharks. They
developed visible sores from bumping into the sides of the tank.
SEAN VAN SOMMERAN: We actually snuck in with photographers and took pictures of the sharks
as they were beginning to attrit and fail due to the constant scraping against the walls
basically. As we viewed it, it was a vase of flowers that would be kept for the visitors.
Historically, aquariums kept sharks that lived near the seabed or near reefs. That makes
sense – it’s easier to recreate those habitats in a tank. But in recent decades,
aquariums have wanted to bring in bigger, more pelagic sharks, those that spend time
roaming the open ocean. They’ve even been able to exhibit the largest
shark in the world, the whale shark, if they have a big enough tank.
But pelagic sharks are used to being able to swim long distances without obstructions,
changing directions only as they please. So the faster-moving sharks like the
white shark, mako shark, and blue shark, they have trouble with walls when they’re
put in a tank. That’s what was happening with the Monterey
Bay Aquarium’s sixth white shark in 2011. They decided to release it after 55 days and
its tracking tag revealed that the shark died shortly after being released. They’re not
sure why. But since then, they haven’t tried bring in
another great white shark. JON HOECH: It’s just a very very very resource
intensive program and we felt like we had accomplished our goal of introducing the general
public to a live white shark. It took a huge, carefully planned system to
keep a white shark alive. And even then, the sharks didn’t quite fit there.
We can’t seem to stop trying though. Earlier this year, an 11.5-foot great white shark
was taken to an aquarium in Okinawa, Japan after getting caught in a fisherman’s net.
It was the only adult white shark ever to be put on display, and within 3 days it was dead. I wanted show you a great resource online
called the Biodiversity Heritage Library – it’s the product of a couple dozen
museums and libraries all agreeing to scan millions of pages from books related to biodiversity.
They’ve got a bunch of great albums on Flickr, including one that’s all about sharks.
Some of these go back to the 16th and 17th centuries, back when the naturalists used to call sharks “sea dogs” which is funny because as we now know sharks were roaming the oceans for about 300 million years before the first mammals showed up.