from the Marine Dynamics Newsletter, May 2009
Greetings,
May has been a month of change for us as the MD boat has been off the water for almost three weeks. The great news is, in this time period the crew managed to strip the vessel down to the bare hull and build it back up again- now Shark Fever is ready to take on the Gansbaai winter sea's with full force, we say if a jobs worth doing- its worth doing well.
Shark wise this month, sightings started slowly for the first two weeks of the month but now finally have started to pick up again. Our first few real winter cold fronts finally hit this month and so as a result we have started to see the arrival of some familiar fins in the bay.
All in one week we had the return of Nemo - our favourite little distorted finned female. A distinctive female with a hole in her dorsal fin from a satellite tag returned in the third week of May (last seen December 2008) and finally...the long awaited Slashfin!
Slashfin arrived in Gansbaai in 2004 with a completely shredded dorsal fin. There are many theories as to how the damage occurred, boat propellers, or a bite from another shark are a couple of examples. Photos of lemon, basking sharks and raggies with similar scarring to Slashfin were confirmed to be the result of bites from other sharks.
Slashfin is one of the most fascinating animals to enter Gansbaai each year and has become a real favourite amongst the shark boats. He has a certain area behind Geyser rock in which if he's picked up by a shark boat he will rush and circle and put on the most amazing behavioural displays.
Personally, I believe from observing his behaviour over a few seasons he is a real seal colony patroller and that Geyser rock is one of his favourite winter feeding grounds. The intriguing thing about this great white is the fact he isn't seen anywhere for the whole year and only shows up at the end of May. He has never been observed in the summer shallows area. It would be fascinating to get a pop up archival tag deployed on this animal to find our where he goes after Gansbaai.
In all though, great to see he's back, still alive and well.
Apart from the return of some well known sharks this month, there has been alot of predation activity. Almost daily, seals are being taken by white sharks or at least attempts are being made.
The Whites sharks seem to be almost pre-occupied with the seal colony this month, which although difficult for cage diving, is great in terms of observing natural behaviour.
Elsewhere in the bay we haven't yet seen the settled return of southern right whales, odd individuals have been sighted, they are due to return any day now.
On almost every trip albatross are being seen from the vessel, stunning winter birds.
Regards
Alison Towner
