Die Burger ran a front page story on Saturday on the results of an aerial survey of Great Whites in Algoa Bay. So, do we need to keep our toes on the nose instead of dangling over the sides of our boards? Not really it seems. Thankfully!
Dr Matt Dicken, though funding via the beach office & municipality, has been keeping an eye on our toothy friends to see what the get up to in our bay.
Lucky, the aerial surveys via chopper never spotted a white off our surfing beaches - the closest one spotted during the 43 flights the ou's did over a 2 year period was about 4k's north of PE Harbour. Most (80%) of the sharks spotted from the air were in an area 6k's north and south of the port at Coega.
Interestingly, the chopper surveys seemed to show a correlation between low water temps (15-17C) and high barometric pressure as being the conditions that most of the sightings were made. Whether the link between high pressure was just due to the fact that chopper flights were mostly conducted in favourable weather conditions, versus there actually being more sharks when the pressure is high, is hard to tell.
In conjunction with the aerial surveys, a total of 59 white sharks were fitted with acoustic tags between March and November 2012. The sharks were tagged at various sites between False Bay and Algoa Bay. An array of “listening stations” were then been deployed throughout Algoa Bay, which are able to detect the presence of any tagged sharks within a radius of approximately 500 m.
Three of the stations that are of interest to us as surfers are located 500 m offshore from Kings Beach, Slipway and Something Good
Information downloaded from these 3 stations shows 9 great whites were detected in the 9 months between May 2012 and January 2013. Five of them were local boytjies who'd been tagged in our bay, and 4 were ou's that had been tagged in Cape Town or Mossel Bay. Most of the sharks were detected in September (6 of the 9).
So, what does this mean for us?
Well, White sharks are present (although very few) throughout the year close inshore at Kings Beach, Slipway and Something Good....but they aren't resident at these sites and appear to be just passing through. Probably en route to/from Bird Island.
Seasonally, more white sharks were recorded inshore during September than any other month. Helicopter and shore angling surveys of the beaches also seem to support the observation that they're more common close inshore during spring and summer.
These results obviously only covers the tagged sharks. It is of course very probable that non-tagged sharks are also present. So as a result, the number of sharks detected by the study may be a very conservative estimate of the total number of sharks about.
The findings are also only for only 9 months. With continued monitoring and with more tagged sharks in the water it is inevitable that more tagged sharks will be detected at these sites. The guys have already tagged 12 more sharks in May and June 2013 and plan to tag another 8 before the end of the year.
Just cos the sharks cruise past fairly close to shore doesn't mean you're gonna lose your toes....cos at this stage their main behaviour seems to be just cruising. However, it is possible that the proposed fish farm just offshore Pipe could attract more sharks and cause them to spend more time in the area....cos there'd now be a reason for em to hang about. Suddenly a whole concentration of potential food, and lotsa activity in the water. Sharks are quizzy creatures, so a moerse bunch of fish in a cage sure will spark their interest.
What's this mean for us? We don't know yet. But it could well increase the probability of a water user encountering a white shark. Not good. One of the many reasons why I think the fish farm idea sucks.
Thanks to Dr Matt Dicken for the info and images.