When Ian Gordon watched a great white shark glide through the tank at OceanWorld in Sydney, Australia, he was ecstatic. For the first time in history, a great white shark had been caught and transported without severe trauma to an aquarium. He bragged to his fellow shark curators that he would be the first in the world to keep a great white - "the Holy Grail" of sharks - alive and well in captivity.
Five days later, he sadly released the shark, which had begun slamming into aquarium walls, back into the ocean. And OceanWorld joined aquariums around the world that have tried and failed dozens of times over the past 25 years to keep great white sharks.The episode last November was testimony to a paradox, says John McCosker, director of the Steinhart Aquarium in San Francisco: "Although sharks are very difficult to kill, in captivity, many are just big babies."
Sharks, it seems, have very delicate constitutions. And great whites - the most fearsome beasts in the seven seas - are probably the most delicate of all.
More temperamental than tropical fish, sharks in aquariums today are pampered with obsequious care more suited to divas of the opera than cold-blooded beasts with a steely reputation for mindless, savage attacks on humans.
In modern aquariums such as Sea World, Monterey Bay or Baltimore, attendants quietly hand-feed sharks small fish stuffed with specially formulated shark vitamin pills, one at a time. The sharks live in enormous tanks - half a million gallons or more - designed to permit them to carry out their unique swim-glide pattern. Curators discovered that some species of large sharks which live in small rectangular tanks spend so much energy thrashing their way out of corners that they consume their livers, which provide ballast. They lose the ability to swim, then die.
The seawater in which sharks live must be the correct temperature, proper salinity, carefully filtered to prevent disease, and, if artificial, the proper chemical formula. Because a shark spends its life in shadowed depths and can see as well as a cat in the dark, lights must be dim. Noisy pumps must be muted.
Electrical hot spots must be eliminated. Sharks are not only excellent detectors of blood molecules. They are also extraordinarily sensitive to weak electric fields generated by wounds and heartbeats. Salt water may create a spot of rust in a tank wall and emit an electrical signal that "drives a shark nuts," said McCosker. "It would be like you or me living at a rock concert day in and day out and screaming, `Is our keeper deaf?' "
Aquarium curators lost hundreds of sharks in the process of learning how to care for them. Twenty-five years ago, the average life span of large sharks - five feet and up - was just two years in captivity.
"No one was doing a good job keeping them," said Frank Murru, director of animal service for Sea World of Florida in Orlando. "Over the last 10 to 15 years, we've learned what makes sharks tick in terms of their behavior and physiology, and we began to create habitats specifically designed for large sharks."
By combining empirical and scientific data, curators and scientists have isolated four steps in the process of adapting a shark to captivity, said Robert Hueter, director of the Center for Shark Research at Mote Marine Laboratory in Sarasota, Fla.: catching them without injury, and handling them so that their organs, which aren't well attached, don't fall out of their mouths; transporting them from the ocean to an aquarium's tank; introducing them to the tank; and adapting them to captivity.
"Some sharks go into physiological stress when they're caught," said Hueter. "You can lose some species very rapidly, in minutes. Hammerheads are very sensitive. Nurse sharks, on the other hand, are almost ridiculous - you can almost put them into a rolled-up wet newspaper and they'll survive."
Some sharks are immediately given an intravenous drip of sodium bicarbonate in their caudal artery to buffer the lactic acid they dump into their bloodstreams when they're under stress. They are placed in special high-tech tanks that pump super-oxygenated, filtered seawater over their gills. If they are still in bad shape when they arrive at an aquarium, they are placed into a small "hospital" tank.
"We treat them like a triage patient," said McCosker. "We've designed a shark brassiere that fits over their pectoral fins and is attached to a harness with elastic bungees so the shark can swim in place." Then oxygenated water can be pumped over its gills, an IV put in its fin, and shots of antibiotics or steroids can be administered without injuring the shark or its attendants.
In adapting the sharks to captivity, said Mike Shaw, curator of fishes at Sea World in San Diego, aquarium staff have learned that "sharks are a very diverse group of animals. The difference between some species of sharks is like the difference between a bat and an elephant."
A bamboo shark spends most of its life lying quietly on the bottom, while a brown shark needs a roomy tank in which to swim continually to breathe and stay alive. Tiger sharks tend to be loners. Hammerheads like to hang out with each other. In some tanks, lemon sharks get along fine with black-tipped reef sharks. In others, they bite them in half.
"Each species has its own swim patterns and behavior," said Marsha Englebrecht, curator at Marine World Africa/USA in Vallejo, Calif. "And within each species, you have individual animals that seem more outgoing, or shyer, to put it in human terms."
Today, of the 375 species of sharks in the world (not including skates and rays), most aquariums easily handle at least two dozen species of sharks, and boast of sharks that have lived for eight, nine, even a dozen years. Ask curators about species that were rare 10 years ago, and they point to their successes with pride: sleek, beautiful black tipped reef sharks in nearly every aquarium, scalloped hammerheads at Sea World in San Antonio, massive whale sharks in Okinawa, a tigershark at Disney World. Ask them about mako and blue sharks, however, and they're back to describing life-and-death struggles. Talk to them about great white sharks and they toss up their hands in exasperation.
None knows why no great white sharks have survived in captivity, and Gordon's attempt just added to the puzzle. Shark experts speculate that, like other temperamental shark species, great whites must be caught carefully, on specially designed hook and line, close to an aquarium, and be placed in a large, cold-water tank. Gordon met the first two requirements.
"Nobody's put all three things together," said Jerry Goldsmith, director of San Diego Sea World's aquarium department.
"Ian's a good shark biologist," said McCosker, "but OceanWorld is an old aquarium. It's got rock piles, electrical fields. It wasn't a good tank."
Most great white sharks that have ended up in aquariums have been caught by fishermen in gill nets that stop the shark from swimming, and, thus, breathing; most are half-dead by the time they are put in a tank. They need colder water - probably no warmer than 60 degrees Fahrenheit - than most aquariums can provide. Because they regulate their body temperatures to be warmer than most species of sharks, they probably need more food. Since they're probably the most sensitive of all the sharks to electrical signals, some scientists speculate that the only way they'll survive is in a giant glass bowl.
Most shark curators and scientists agree that before any aquarium will be successful in keeping a great white shark, more needs to be learned about the species - such as its swimming characteristics, electrical sensitivity, and preferred light, depth and temperature levels. As with any shark, said David Powell, director of the department of husbandry at the Monterey Bay Aquarium, "we've got to try and duplicate what we see them doing in the wild."