Posted on Tuesday, 6 October 2015
As expected I bring news of the 2015 Great White shark season at Seal Island, Cape Town having come to an end.
The end of the season always brings with it a mixture of sadness of not seeing the Great Whites for the next 4 to 5 months and a sense of reflection. It also leaves me thinking again how quickly yet another season has run its course and that perhaps the many long hours spent at sea now mean a good rest for our team.
Our last shark sighting was on the 9 September and leading up to this point we had successful trips. A couple of the days had quiet activity due to pretty nasty sea conditions but as we were hosting an expedition it meant all the guests still had good opportunities on a number of days.
We were seeing between 1 and 4 sharks per trip that were mostly interactive and staying around long enough for everyone to have great views of them. Two of the sharks were 2015 season regulars and they were the most interactive. These were a large female, Scarlett, who we have seen consistently since July and Madonna, a medium sized female with a white injury stripe above her left eye making her very easy to identify, also seen on and off over the last 2 months.
Usually towards the end of the season we see predation events but the sharks were less and less interested in coming up to the boat. As with everything this season, things were a little different this year. We were seeing few predatory events and when we were seeing events there were no long chases. The events were also very spread out with no real pattern to the activity. This made it challenging to see any initial attack on a seal and with a high volume of seals returning to Seal Island in the pre dusk it also made it challenging to be in the right place at the right time with so many seals to monitor. The sharks also displayed classic end of season behaviour of not consuming the whole seal carcass as well as taking longer than usual to eat the seal.
We did get 3 breaches on the decoy in the first week of September which was a real bonus for all on board considering how little predation activity we were seeing. One of the breaches was a fantastic head on breach with the shark half way out of the water.
Pelagic Shark Trip
If you have been following Shark Bytes this season you will know that we really battled the weather conditions and flat calm seas were a rare occurrence. Given that we were hosting an expedition in September and already had a number of good Great White shark trips and received an almost perfect weather forecast, the group enthusiastically agreed to head off Cape Point in search of Mako and Blue sharks. As we rounded Cape Point in inky calm seas we sighted our first group of Humpback whales of the day.
As we pressed further into the open ocean in search of the Agulhas Current we started seeing many species of pelagic birds including three different species of albatross.
At about 20 miles off Cape Point we found 16 degree Celsius water and good visibility of about 12 meters. We began our preparations for attracting sharks to the boat expecting, as we normally do, the first shark to arrive within 20 minutes. After an hours wait we felt sure it would be any moment until a toothy visitor arrived… At 1.5 hours we began to wonder if there were any sharks around at all, and at 2 hours we were sure we would be skunked for the first time in many years off Cape Point on a pelagic shark trip!
So, when a tiny 80cm blue shark finally arrived at the boat we were all over the moon. Soon afterwards more blue sharks started to arrive and we ended the day with about 15 different sharks in total. All the guests on board were true shark fanatics and really appreciated these beautiful sharks in such great conditions. Because the sea was so calm some of the guests were able to free dive outside the cage and I know for many of them this was a life’s highlight.
The day was not over yet as the flat conditions provided ideal spotting conditions. We came across a small school of Common dolphin and at Cape Point we counted in the region of 8 to 10 Humpback whales. All in all it was an incredible marine wildlife day and we are really looking forward to getting back into Pelagic Trips this summer!
Once the expedition finished we had two more days of shark sightings on our scheduled Morning Trips before a very fresh and strong South East wind blew us off the water for 6 days. Our first day back on the water was also our first trip with no sharks sighted and signalled the end of our season.
Seasonality at Seal Island
There could be a number of factors that cause the sharks to leave Seal Island. The young of the year seals that the sharks almost exclusively feed on have by the middle of September become far wiser and perhaps less easy to catch. Big bulls also slowly start to arrive for the breeding season and perhaps the sharks prefer to steer clear of this potential threat.
Another very plausible reason could be that prey availability changes within False Bay. Spring usually signals the arrival of warmer water currents in False Bay which brings with it a whole eco system starting with mullet and bait fish which in turn attracts game fish and other species of sharks. These smaller summer shark species (Smooth Hound and Soup Fin sharks) make up a large part of the Great White shark’s diet and it makes sense that the sharks will leave Seal Island for more suitable options.
Reflections on the 2015 Shark Season
Reflecting on the 2015 Seal Island shark season I have to admit that it had its challenges! The biggest challenge was battling the strong South East wind that prevailed over almost the entire winter. This wind is our summer wind and makes the sea very uncomfortable as it blows directly into False Bay with no lee to offer protection.
We also know that the onset of a cold front normally stimulates intense periods of predatory behaviour. With very few, and on top of this very weak cold fronts, it meant that conditions were perhaps not optimal for the Great Whites to hunt the Cape Fur seals.
Red Tide was also milling around False Bay for the whole winter. We know that the red tide causes very low levels of oxygen in the water and this could well have added to less than perfect conditions for the sharks.
Our sightings are unfortunately down in both numbers of predatory events recorded and also in numbers of sharks recorded around the boat. You may all recall we went 57 days of no sharks between April and June, a time that should be moving into the peak part of our season.
Finally, we only recorded 2 of our regular Seal Island sharks that we usually see from year to year. We desperately hope that this was due to poor environmental conditions rather than something untoward having happened to them.
It’s interesting to note that Gansbaai has also had similar challenges which makes me think more and more that environmental conditions are having a strong effect on the shark activity.
The biggest lesson for me this season has been to appreciate seeing just one Great White shark, no matter how brief the encounter. Great White sharks are extremely rare animals; some experts claiming a worldwide population of only approximately 3500 individual sharks. Each one is precious and each sighting should be seen as a privilege rather than a disappointment that more sharks were not seen.
I’d especially like to thank our new boat crew this year who faced all the challenges so expertly as well as the many wonderful guests who really appreciated the life experience of seeing a Great White shark.
And last but not least…Thank You Sharks! February 2016 cannot come soon enough!
Chris & I depart shortly for a month in the Zimbabwean bush but I will be back in November with a few land-based nature experiences.
To read our last three Shark Bytes click on the links below:
August 2015 Shark Bytes
July 2015 Shark Bytes
June 2015 Shark Bytes