R43 Padgebruikers Kla: Padmakers Moet Spoed V...
Gansbaai Courant het heelwat klagtes van padgebruikers ontvang dat die R43-pad tussen Stanford en Gansbaai onveilig is.
“This is the 5th white shark carcass, and the largest to wash up in Gansbaai since 2012,” says Alison Towner, white shark biologist for the Dyer Island Conservation Trust. “On Wednesday, 3 May 2017 at 07:00 a deceased white shark was reported at the beach in Franskraal.”
Wilfred Chivell co-ordinated with his team from Marine Dynamics to retrieve the shark with the Samil a research boat, assisted by the International Marine Volunteers. The Department of Environmental Affairs have permitted an onsite dissection with shark expert Dr Malcolm Smale, who has flown in from Port Elizabeth, together with members of the National White Shark Research Group.
“The shark is a 4.9m female (total length) and we estimated her weight at 1,110kg. We have her recorded around Dyer Island last year in June but we haven’t seen her since”, says Towner.
“She has also been recorded in Mossel Bay between August and December 2016. At this size, she is likely reproductively mature - which is rare to see and so impressive.
Again there is much speculation flying around about Orcas killing the shark. There is a gaping wound on the sharks underside.”
It is the biggest white shark dissected in South Africa. However one major observation is that the shark was missing its entire liver. The report has not been finalised, but it is very likely that an orca may have been responsible for this type of injury.
4 May 2017
Another white shark was found on Franskraal beach at 05:00. The team went straight there to recover a 3.4m male who is missing big pieces out of each flank. Alison Towner with Dyer Island Conservation Trust and Dr Malcolm Smale conducted a dissection the next day. This specimen is in a more degraded state and cannot be frozen.
This shark is also missing its entire liver and heart, again a near certain indication of an orca attack. Guiding biologist, Kelly Baker, matched this shark as one she had photographed on the 29th of April 2017 inshore on the Joubertsdam reef. She was able to recognise the shark using markings on the lower caudal fin (tail).
Towner says: “Today's necropsy will be quicker than the 4.9m female due to the mutilated state of its body and missing organs, many measurements will not be possible.
This is a difficult yet fascinating time. Something rarely documented in marine top predator behaviour in South Africa,” says Towner.
7 May 2017
At 12:00 a third deceased white shark washed ashore, this time in Struisbaai. The NSRI site manager notified Dr Alison Kock and the white shark research group. It was decided that the Dyer Island Conservation Trust team were the closest to the site and so they dispatched their team once again to go and retrieve the shark carcass using two 4x4 vehicles and a small vessel trailor. “We have never seen anything like this. This carcass is another large white shark, he is a 4.2m male and his injuries seem to match those of the previous two dead specimens,” says Towner.
At the end of another long day, the third white shark necropsy in 7 days, and hopefully the last. This one took 6 hours to complete and was led by Alison Towner herself, with support from Marine Dynamics biologist Kelly Baker.
Parasites such as copepods and nematodes are extracted and preserved, muscle tissue is preserved for genetics diet and physiology studies and all the wounds measured and examined closely.
This white shark was a mature male of 4.5m with fully calcified claspers.
His open wound was located under his left pectoral and exposed his body cavity.
His liver had been removed, but unlike the smaller 3.5m white shark, he still had his heart in place.
“It is a very interesting time,” says Towner, “the last white shark washed up here on the 8th of February and the cage diving boats struggled to see any sharks for almost two weeks.
Unfortunately the cage diving boats all came home after seeing no sharks.”
The final results in this case will be available soon.
The follow-up information can be seen on
