Two more whale sharks have been installed at the Georgia State Aquarium in an apparent attempt to establish a captive breeding programme. The aquarium, the world's largest, was a $250 million gift to Georgia from Bernie Marcus, co-founder of ‘The Home Depot’, and caused controversy with the arrival of the first two whale sharks last year.
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Young
whale shark in the Ocean Voyager tank at Georgia
State Aquarium. Photo, Georgia State Aquarium |
The two new arrivals are young female whale sharks, of 3.3 and 4.2 m, who join the two 5.4m males that have been in captivity for around a year now. Jim Tharpe, from Cox News Service, reports that “Aquarium officials say they have all the ingredients in place to produce baby versions of the biggest fish on Earth at the world's biggest indoor fish tank. They just need a few years and a lot of help from science and nature.”
Shark expert Bob Hueter said it could be several years before the big fish reach sexual maturity but "If it can be done, this is the best facility in the world to make it happen… It's the only facility in the world that can make it happen". Hueter is the scientist in charge of the Georgia Whale Shark project and director of the Center for Shark Research at Mote Marine Laboratory in Florida. He currently leads a whale shark research programme in Cancun & Holbox, Mexico funded by Mote Marine Lab and the Georgia Aquarium.
There are however some very big question marks about breeding whale sharks in captivity, not least being the lack of real knowledge about their mating and birthing habits. "One of the things that's a real question mark is how fast they grow in captivity and whether their hormonal systems keep pace," Hueter said. "If they can grow 3 feet per year, the larger ones could be at a sexually mature size in four to five years. In that time, there could be some reproductive activity". Records from captive-kept whale sharks in Japan indicated that growth rates can be this fast for very small sharks below 3 m but slow dramatically from 21.5 to 29.5 cms (less than 1 foot) per year
(Marine Conservation News
3.1). If this is the case then the Georgia aquarium could be waiting an awful long time before the sharks are big enough to start even thinking about reproducing.
The other issues have to be whether the sharks will be able to survive in captivity long enough to get to reproductive size (over 8m), the record in Japan is around 10 years, and whether the enormous 22 million litre Ocean Voyager tank is big enough to house four 8m+ whale sharks…..
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