For the second time, the Monterey Bay Aquarium has introduced a young Great white shark into its public exhibit, two weeks after collectors caught the fish on a rod and line off southern California.
The new Great white shark, Carcharodon carcharias, which measures around 1.72m/5'8" and weighs about 47 kg/104 lbs, was caught several miles offshore in Santa Monica Bay and had been held in a 4-million US gallon pen off Malibu since mid August to check that the fish was feeding happily before introduction.
The new shark has eaten for the first time in eight days and is reportedly bringing in record crowds to the Aquarium.
The Aquarium previously displayed a Great white shark in its exhibit for a record 198 days in late 2004, after successfully managing to wean the fish onto dead foods while it was being held in a sea cage. The shark was returned to the wild six and a half months later and tracked using a sophisticated tag.
The Monterey Bay Aquarium runs the White Shark Research Project, which aims to learn more about white sharks and to bring in a shark for exhibit at the facility to allow closer study. The Aquarium says it has tagged and tracked seven juvenile white sharks since 2002 which were caught by biologists or anglers off southern California. It is also collecting DNA samples from the fish to allow the population structures of the sharks to be examined.
Dr Mike Murray, the staff veterinarian at the Aquarium, said that it prefers to try and catch its own sharks to use in the exhibits, as they take efforts to minimise the stresses of collection, holding and transport:
"There are lot of unknowns with sharks that are bycatch from a commercial fishery," said Murray. "We never know how long they've been in the net, or to what degree their health is compromised. We have much more confidence that we have a healthy animal to begin with when our team does the collecting."
This year, the Aquarium has worked with six Great white sharks caught accidentally by commercial fishermen. One escaped, one was released because it wasn't suitable as an exhibit, one was tagged and released in the field, and three others died.
Upon capture, the fish are kept in a giant sea cage and monitored to see how they cope with life swimming in an enclosed space. The team also try to wean them onto food, including salmon fillets, mackerel and other fish, to determine that the fish are feeding healthily before introducing them to the aquarium. The previous inhabitant at the Aquarium was the first Great white that aquarists have managed to wean on to dead foods to date.
The first Great white that the Monterey Bay Aquarium kept didn't take too well to living alongside other fish. It was introduced into the Aquarium's Outer Bay exhibit where it lived alongside pelagic fish including Galapagos and Scalloped hammerhead sharks, as well as Bluefin tuna, Yellowfin tuna, Barracuda, Ocean sunfish and giant turtles.
While the shark lived alongside its other tankmates relatively peacefully, it's behaviour changed in February 2005, and it began actively hunting the other fish in the tank, resulting in the death of two Soupfin sharks. It was subsequently returned to the wild, with a radio tag, a few days later.
The Great white - the star of Jaws - is the world's largest predatory fish, reaching an average length of 4.7m/15', with some specimens reaching up to 6.5m/21.5' and weighing in at a massive 1800 kg. The slow rate of reproduction and the slow population doubling time means that the species is at risk from exploitation.