Can We Save Sharks?

Bubbling water echoes around a biologist at Sea Life Sydney Aquarium in Australia. She leans over a tank to pick up a zebra shark egg. The baby shark growing inside the brown leathery pouch is about to go on an incredible journey. It will travel more than 5,200 miles by car, airplane, and boat from Australia to a remote island in Indonesia (see Going the Distance, below).

Why go to such great lengths for zebra sharks? This endangered species needs all the help it can get. Unfortunately, it isn’t the only one. Of the 1,199 shark and ray species on the planet, more than one-third are threatened with extinction.

In 2019, biologists from around the world gathered to see what they could do to help. They discussed the idea of transporting sharks bred in zoos and aquariums to their native habitats, and the ReShark program was born. Today more than 90 aquariums, conservation groups, and government agencies are part of ReShark.

After years of planning, the first captive-bred sharks were released in January 2023. “It marked an incredible milestone for us,” says Erin Meyer, chief conservation officer at the Seattle Aquarium. “We’re now ready to scale up!”

The sound of bubbling water fills an aquarium in Australia. A biologist leans over a tank to pick up a zebra shark egg. There’s a baby shark growing inside the brown leathery pouch. And it’s about to go on an incredible journey. It will travel more than 5,200 miles by car, airplane, and boat. It will travel from Australia to a remote island in Indonesia (see Going the Distance, below). 

Why send a shark so far? Zebra sharks are an endangered species. They need all the help they can get. Unfortunately, they aren’t the only ones. There are 1,199 shark and ray species on Earth. More than one-third are threatened with extinction.

In 2019, biologists from around the world decided to help. They planned to breed sharks in zoos and aquariums, then transport them to their natural habitats. They called the program ReShark. Today, more than 90 organizations are involved.

Starting the program took years of planning. In January 2023, the first sharks bred in captivity were released. “It marked an incredible milestone for us,” says Erin Meyer. She’s the chief conservation officer at the Seattle Aquarium. “We’re now ready to scale up!” she adds.

Why were zebra sharks chosen for the first project? This species lays eggs instead of having fully-developed young. This means aquariums could ship the eggs to their new home, which would be easier to do than sending live baby sharks. We also already know a lot about zebra sharks: what they eat, when they’re ready to mate, and how long they live. “We know a lot about their basic biology because they’ve been in human care for so long,” says Meyer.

ReShark partners designed and built two nurseries in Indonesia. Once the eggs hatch, local biologists monitor the baby sharks and then release them when they are big enough to live on their own.

The nurseries are located at the Raja Ampat Research and Conservation Centre on Kri Island and the Misool Foundation’s resort on Batbitim Island. Both are in a marine sanctuary created in 2012 that protect sharks and rays. Fishing is prohibited in this network of aquatic habitats that covers more than 7,700 square miles.

Today, there are more and more black-tipped reef sharks and mantas in this marine park. But zebra shark numbers have yet to bounce back. The baby sharks will eventually be released near the nurseries. Biologists hope that they will stay within the boundaries of the protected marine park where they can grow without the threat of human predators

There’s a reason the scientists chose zebra sharks first. Many sharks and rays give birth to developed young. But zebra sharks lay eggs. Shipping eggs to their new home is a lot easier than sending live baby sharks! Scientists also know how to raise zebra sharks in captivity, says Meyer. “We know a lot about their basic biology because they’ve been in human care for so long,” she says.

ReShark helped design and build two nurseries in Indonesia. The eggs are sent there to hatch. Local scientists then monitor the baby sharks. They’re released when they are big enough to live on their own. 

Both nurseries are located in a marine sanctuary. This protected area was created in 2012 to help sharks and rays. Fishing is prohibited in the sanctuary. It covers more than 7,700 square miles.

The marine park is already helping some species. There are more and more black-tipped reef sharks and manta rays than there were in 2012. But zebra shark numbers have yet to bounce back. ReShark scientists hope to change that.

The baby sharks will eventually be released near the nurseries. Scientists hope that they will stay within the marine park. That way they’ll be protected as they grow. 

On January 13, 2023, two of the first four sharks were released. Scientists, government officials, and others gathered to watch. Each shark was outfitted with a monitor to help researchers see where it travels. So far, they have seen two of the four released pups in the wild.

Biologists hope to release up to 500 zebra sharks over the next decade. About 20 more shark pups are now growing in the Indonesian nurseries. Scuba divers and snorkelers can come see them.

ReShark’s partner aquariums plan to send more zebra shark eggs to Indonesia this year. Biologists are also getting more aquariums in Europe to join the effort to help diversify the shark gene pool.

If the zebra shark program is successful, it can be a model for other endangered shark and ray species too. “There are more critical species out there,” says Lisa Hoopes, the director of research and conservation at the Georgia Aquarium, another ReShark member. “We can take advantage of the knowledge of zoos and aquariums to help contribute to these efforts.”

On January 13, 2023, the first two sharks were released. Scientists, government officials, and others gathered to watch. Another two sharks were released soon after. Each one wore a monitor to help researchers track it. So far, two of the four baby sharks have been spotted in the wild.

Scientists hope to release up to 500 zebra sharks. They expect it to take a decade in all. Right now, about 20 sharks are growing in the nurseries. People can scuba dive and snorkel to see them. Aquariums plan to send more zebra shark eggs to Indonesia this year.

The zebra shark program could help more than just zebra sharks. If it’s successful, scientists can copy it for other endangered sharks and rays. Lisa Hoopes is the director of research and conservation at the Georgia Aquarium. “There are more critical species out there,” she says. “We can take advantage of the knowledge of zoos and aquariums to help.”