August 2014 Shark Bytes
Posted on Monday, 1 September 2014
Dear Shark Lovers,
I am very happy to report that we have managed to survive through August and as of right now we still have a number of Great White Sharks present at Seal Island. This is great news as I really thought there was a chance whilst writing July’s Shark Bytes that we would have reached the end of the season at this point! In this report I will be talking about the up and down activity of the predatory events, how weather has played a part in our sightings and of course observations of who exactly, in terms of sharks, has been around this month.
Historically over the last 18 years the middle of July to about the 10 of August has always been the time period where we record and observe the most intense amount of predatory events. I have already reported in July that the activity had fallen well short of what we normally see.
As we went into the early part of August activity remained low with sometimes no events at all to perhaps a handful each day.
We did have the chance to watch and photograph one particularly spectacular event where a very large shark we estimated to be over 4 meters in length did a massive full breach through the middle of a group of seals. The seals scattered everywhere as the huge shark came bursting through and on this occasion the shark was successful. With 8 different events on this day it was our busiest day of the previous 2 weeks.
Shortly after this events slowed down again and the actual predation events starting taking on a new type of behaviour of very slow consumptions of the seals carcass on successful events.
Normally events take place very fast and the seal is eaten in a matter of moments. We think this is due to pressure from other sharks in the area making it a realistic possibility of the successful shark losing its kill to another shark. You can appreciate that the splashing and noise from the chase will attract other sharks to the area and there is no way a shark would want to risk losing its meal. Also remember that in terms of shark hierarchy the bigger sharks dominate, and smaller sharks can easily lose their kill just by larger sharks using their muscle so to speak.
Over about a week to a 10 day period we observed sharks taking a long time to consume their kills, sometimes for up to 5 minutes long. It always fascinates me how aware the sharks are of energy conservation. A slow, laborious feed will take far less energy than a rather violent and thrust-filled consumption. When there are far fewer sharks around, and the threat of losing a kill is far less, there is no need for a shark to use the same energy compared to a pressure situation. This also shows that the sharks are very well aware of how many sharks are currently in the area, and possibly which actual sharks are present too.
So, although we were not seeing high amounts of predation it was still very interesting for ourselves and our guests to observe this kind of feeding behaviour, and of course it was a great chance to watch a shark feed and get a really great look at that individual.
This slow consumption has definitely been an indicator over the years that the season at Seal Island is starting to slow down as the sharks move into other feeding areas such as the inshore waters of False Bay and up the coast.
We were also struggling somewhat to observe sharks around the boat. We did have a complete miss on one trip but the average was 1 to 3 sharks per trip. So, you can appreciate that our thoughts were definitely that the end was imminent!
How Weather Affects Activity
However, Seal Island still had a few tricks up her sleeve and just after the middle of August we had one very good morning of 10 predatory events and 6 sharks at the boat. This morning was just preceding a fairly big low pressure system (ie bad weather) and we certainly know from our data collected over the years that low pressure systems do definitely stimulate the sharks to hunt. This may be due to the higher numbers of seals returning to Seal Island to shelter from the weather (which equate to more hunting opportunities) as well as sea and climate conditions that serve to aid the sharks in being more successful.
In the week after this we witnessed events on all mornings. This coincided with our annual Great White Trail Expedition so we were thrilled that the expedition members got to experience the natural predation activity that makes Seal Island so famous. The Great White Trail is a trip designed to take in all 3 Great white shark locations in South Africa. Starting in False Bay the focus is to view natural predatory events and then moving along to Mossel Bay and Gansbaai this time of the year provides excellent cage diving opportunities.
At Seal Island we saw hunting events in various degrees of spectacular-ness (is that even a word?) but we also had good sightings of sharks around the boat. On our last day we had an extremely obliging and relaxed male that stayed with us for most of the morning. The weather was perfect and the flat, glassy sea made the encounter with this shark very special. The predation events are always a highlight to see but for me nothing beats a perfect day with a slow, relaxed shark gently cruising around the boat…. That is when one really connects with this amazing animal!
The whole Great White Trail group was made up of some serious shark and nature lovers so it was fantastic to be able to share this with them. Although weather did not allow them to get out in Gansbaai the 3 days in Mossel Bay was very successful with high shark numbers around the boat. We already can’t wait for the 2015 Expedition!