Shark Chronicles 019 – Following a white shark in unknown waters
Posted by Enrico Gennari on July 30, 2008
SAMPLA team managed to tag a large 3,8 meter white shark (which was previously tagged with a satellite tag) following it for a day and an half inside and outside Mossel Bay.
We affectionately named this shark Roxanne after the popular song by the Police that SAMPLA scientist Stephen (who tagged the shark) always sings while chumming. The shark didn’t leave the proximity of the boat for a while providing the team with the chance of also taking a genetic sample. Then the forecasted bad weather hit Mossel Bay ending the tracking.
But SAMPLA scientists and students didn’t want to loose such an important shark. Thus Enrico and his team sailed the choppy waters of Mossel Bay looking for the presence of Roxanne using the onboard omni directional hydrophone. After a while they found her moving northward away from seal island. Five hours of tracking, and close encounters with dolphins, humpback and Southern right whales, took Roxanne to reach Grootbrak, a famous fishing ground.
Ryan and his team took over at about 1 o’clock at night while Roxanne start heading back toward Seal Island. The sea at night here is something different…unbelievable. We had for most of the cold night Cape fur seals all around our boat, playing through the bioluminescent plankton, resembling a flying object which leaves a glowing ink behind. Even more breathtaking was watching a white shark’s silhouette like a silent U.F.O. passing underneath our boat with the background of orange lightings due to a thunderstorm at the horizon.
At 9 a.m. Roxanne’s fin decided to brake the water less than 200 m from the shore while clueless passers where enjoying the morning breeze on the beach of Mossel Bay.
Steph's team picked Roxanne up in the center of the bay not knowing what was about to happen. Indeed, Roxanne decide to leave the bay, a behaviour which SAMPLA team had have never witnessed or recorded on data. She start moving south, fortunately following the coast. Steph’s team tried its best to keep up with Roxanne, further and further away from Mossel Bay, knowing that because of the limited amount of petrol on the boat they could not carry on too long. Anyway Roxanne decided to moved closer inshore, and the breaking waves disrupted the signal to the extent that the team lost the shark. After more than an hour trying to relocate Roxanne, the team gave up heading back to the safer waters of the harbour.
Nevertheless we know that Roxanne sooner or later will be back in Mossel Bay and SAMPLA will be there to learn more from this amazing specimens, the first white shark ever tracked with acoustic technology while moving between two aggregation sites.