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Shark tag alert

shark tag

Beachcombers, keep your eyes peeled for strange pointy items washing up on the Derwent’s shores.

Researchers at UTAS’ Institute for Marine and Antarctic Studies are hoping locals will find three important shark tags and are offering $100 reward for each tag found.

PhD candidate Killian Stehfest said the pop-up archival tags, which measure light, temperature and depth from sunrise to sunset, were attached to five female broadnose sevengill sharks – one of the most common predators in Tasmania.

The sharks are found in Tasmanian waters between September and May. Previous studies have found the males move to warmer waters near Batemans Bay in NSW during winter, but sex segregation is common among sharks and until now it has been unknown where the females travel.

Killian said it appeared at least one of the tagged female sharks had gone south.

The sharks were tagged in May and the tags have recently popped-up. Two popped up far offshore, but three are in Fredrick Henry or Norfolk Bay and Killian is hopeful of finding them.

“It’ll give us a lot more data on dive behaviour,” he said.

The tags have transmitted information via satellite; however it is far less detailed than that actually stored on the tags. The satellite information provides daily information about the percentage of time the sharks spend at certain predetermined depths. But the tags themselves are able to provide dive profiles second-by-second.

The tags are labelled with information about returns.

Photo: A shark tag.

Published on: 17 Oct 2011 11:21am