October 2008 Shark Bytes
Posted on Friday, 31 October 2008
Dear Shark lovers,
Chris has always been lucky with sharks but 2008 is now the third year in a row where we have not seen great white sharks at Seal Island on his Birthday! So, up until 21 September we were still seeing good numbers of sharks but since then it has been very quiet.
The End of the Great White Shark Season
The end of the season at Seal Island usually ends very abruptly and our first indication of the end of a season is when we arrive at the Island and there is a dramatic change in seal behavior with seals happily cavorting in areas where they previously feared to swim.
This change in behavior is usually the precursor to waiting the whole day and not seeing sharks. During the winter months when the Great white sharks are hunting the cape fur seals the seals stray only a safe distance from the Island where it is too shallow and turbulent for the sharks to venture.
When the sharks are no longer at Seal Island the seals seem to know this and they venture much further out and sometimes hundreds of them can be observed lazily floating on the surface in normal danger zones.
The departure of the Great white sharks also coincides with the return of the bull seals. These males are formidable predators in their own right and we believe that they must pose considerable risk to the Great white shark if the two had to come into contact.
The large bull seals can weigh up to 300 kgs (660 pounds). They return to Seal Island at this time of year for the breeding season, having spent the rest of the year offshore in their feeding grounds. They establish large harems with the more dominant males establishing these on the high parts of Seal Island.
An interesting fact is that the females are also pupping at this time. When they mate with the males they are able to retain the sperm and only fertilse a few months later. This allows them to get the timing of the gestation right and only pup at the suitable time in October/November the following year.
A number of Great white sharks have also been sighted close to the beaches along False Bay which is typical summer behavior for the sharks. We first made note of this in 1997 and the behavior has been consistant ever since. This is yet another indication of the change of seasons. With more great white sharks, as well as other migratory species of sharks, moving close to shore water users do need to be aware of this as there is a greater chance of an encounter.
A Tragic Event
I am sure that many South Africans will have read in the news that a 4.6 meter (15 foot) male Great white shark washed up dead on Macassar Beach in False Bay last week.
The cause of death is not known but is seems to be too much of a co-incidence not to suspect foul play. This is exactly the same area a similar sized shark washed up a few years ago after it was caught in an illegal gill net set at night.
Macassar is a well known commercial shark fishing spot (mostly for Bronze whalers, soupfin, and smooth hound sharks). The commercial fishermen are made up of line fishermen fishing mostly for soupfin and smooth hound sharks as well as a shark longlining operator.
Against all wisdom and general scientific consensus this license was issued in 2008 without any research. The longline is set exactly where the great whites patrol in summer.
In conjunction to this many sport anglers also fish for sharks from the beaches here. Is it a co-incidence that we are seeing dead sharks washing up and other well known sharks seen regularly for over a decade missing, perhaps, perhaps not
The Great white shark is protected in South Africa and these sharks may not be caught or harmed but as compliance and enforcement is currently not up to scratch it would appear that some people are trying to do their best to kill these majestic and charismatic animals for a set of jaws and dried up fins.
Alison Kock, who researches Great white sharks in False Bay, had actually had the shark that was killed up at her boat in 2005 and earlier this year. We had not seen this shark before but it was very sad to hear how she described this male as a very interactive shark around the boat. To see a large Great white shark like this is very rare and even more so because it was a male of that size.
At 4.6 meters this shark would have definitely been sexually mature. This would have made it an extremely valuable individual in terms of his role in reproduction and in all our years at Seal Island we have only EVER seen one other male of a greater size. We believe that each Great white shark is valuable to the population, but this one was especially so.
There are more than a few sharks that we know very well that have not been sighted in the last 2 years and their well being is very concerning to us especially when events like this happen and whispers of a Great white shark poaching problem are becoming louder.
Anybody suspecting any great white shark poaching is free to email us the details which we will pass onto the relevant authorities.
All emails will be treated with strict confidentiality.
We are not normally in Cape Town in October and November but this year we have been home needing to take care of some issues. The good news is we have been able to run a number of pelagic shark trips and the results have been surprisingly good. We have seen good numbers of blue sharks and also a mako shark. The water visibility has been great and the water temperature a not too cold 18deg Celsius.
We have previously offered this trip as a free diving trip only but the last few trips we have been able to take the shark cage out there as well. This has been working fantastically well as it still allows the less experienced divers to see these sharks underwater in a comfortable environment. The other positive is that when conditions are not optimal for free diving it is still possible to dive in the cage.
If the wind does not blow too strongly in November we should be able to get out there as often as possible.