DUBAI // Here’s a handy tip: turn most sharks upside down and they fall into a sleep-like trance.
But rather than the more obvious applications, experts at the Dubai Aquarium and Underwater Zoo use this fact to check the health of their more than a dozen sand tiger sharks – without an anaesthetic.
“It’s a lot better because they can swim away immediately after the procedure, but with anaesthetic it may take them an hour to be back to normal,” said Paul Hamilton, general manager and aquarium curator.
The 2-metre fish have for the past few months been the subjects of world-first research to better understand their breeding patterns, which could ensure the future of the species.
“We’ve a team of divers who use PVC pipes to direct the shark into a bag, then we take it to a research area where we collect samples and check on them,” said vet Marta Munoz Baquero. “It can be tricky to guide the animal where we want it but it’s done in a way that puts as little stress on them as possible.”
Each shark is tagged and every six weeks blood samples are taken. Oxygenated water is pumped through their gills. The females are given an ultrasound and semen is taken from the males.
“Sand tigers have a seasonal breeding phase for males and females, so our focus is on finding out when that is then inseminating them,” said Mr Hamilton.
When the sharks are found to be in season they are checked to see if they have bred naturally before they are artificially inseminated.
“To help the process along, we change the temperature in the tank to match seasonal conditions,” he said.
The collection process takes no more than 10 minutes before the big fish are released.
All the samples are then taken to the in-house laboratory where hormone levels in the blood are tested and the viability of the sperm checked.
Jon Daly, a research consultant who is leading the project, said thousands of samples could be stored in the lab’s cryogenic bank.
The samples, which are in 0.5-millilitre straws, are slowly frozen over a small bath of liquid nitrogen as it warms.
“The nitrogen temperature is minus 196°C, so it would be too much of a shock to the samples and they would freeze too quickly and cause damage to them,” said Mr Daly.
“But in this way we leave them just above the bath for about 20 minutes so that they cool down slowly before placing them in storage.”
Over time many other species of animal could be added to the bank.
“The aim is to have the science and technology in place so governments have the option to reintroduce species into the wild if they wish,” Mr Daly said. “We have a long way to go but so far things are progressing well.”
The work in Dubai will be shared worldwide.
Visitors to Dubai Aquarium and Underwater Zoo can see some of the work done in the lab as part of a behind-the-scenes tour.
Visit thedubaiaquarium.com or call 04 448 5200.
nhanif@thenational.ae
