Captive-bred sharks set free


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Seven captive-bred sharks have been released into the wild in Sydney in what experts are claiming is a first for Australia.

The two-year old Wobbegong sharks, which are members of the genus Orectolobus, were released into the wild at Manly's Shelly beach this week.

The fish, which are around 80cm long, were first fitted with internal and external tagging devices allowing scientists to monitor their behaviour and movements after release.

Dr Vic Tappen from the Department of Primary Industries told ninemsn: "We've got these tags in them and out there we have a array of listening stations so we can pinpoint the exact location of where they are.

"Every one of these guys, we can track their daily moments, their hourly movements, their movements by the second can be tracked."

According to Dr Charlie Huveneers of the Sydney Institute of Maritime Science, the release of the captive-bred sharks is a first for Australia.

Huveneers told The Sydney Morning Herald that the he had previously fitted six wild Wobbegongs with similar tagging devices and had been monitoring them since the beginning of the year.

His aim was to compare the movements and migrations of the captive-bred fish with wild ones to determine whether they behaved naturally after release.

Huveneers told ninemsn: "Sharks have a very slow reproductive rate so we never consider captive-bred sharks to be released into the wild to replenish a population.

"If aquariums have enough sharks then they begin to exchange them, but because there are large numbers of these sharks they are happy to release them."

Wobbegong sharks, which get their name from the aboriginal word for "shaggy beard", are also known as carpet sharks and spend most of their time resting on the sea bed.

There are around eight species in the Orectolobus genus, which reach a maximum length of around 3m/10'.

In 2006 a new species from the Wobbegong genus was found off the coast of southern Australia. The fish, which was named Orectolobus hutchinsi, has dark brown saddles on its back and lacks the white spots or blotches seen in some other members of the genus.