August & September 2008 Shark Bytes
Posted on Tuesday, 30 September 2008
This update is a little late so my apologies. I am going to update you on our shark news for August and September so you may need to find a quiet moment to enjoy hearing about the sharks.
In July I mentioned that the predatory activity was great down on years gone by and we were wondering if it would be happening at all this year. True to form days after this comment the tell-tale signs of intense predatory predation stared to show.
On one particularly miserable Sunday morning we had to delay our departure time due to pelting rain. When we eventually arrived at Seal Island a large shark breaching out of the water in pursuit of a seal made it immediately evident that the sharks were in hunting mode.
I think we recorded a total of 18 events that morning and on top of this we seemed to be close enough to may events that we were able to see the entire event from the initial breaches to the seal eventually evading, or not.
On one particular event a large shark breaching as high as I have ever seen a shark breach. It completely missed the seal but the launch itself must have been a good 2 meters clear of the water, indeed an impressive sight.
We also observed a good number of prolonged chases. The rain was torrential and the wind moderate so each turn was made even more dramatic as the spray was intensified by the elements.
I was so enthralled by what we were seeing I spent the entire morning standing in the pouring rain, and quite frankly I hardly noticed!
Having been at Seal island for the last 9 seasons I can honestly say that it is possible for us to get a feel for the cycle of the behavior that takes place, or is about to take place. In the following days we could feel the build up and with a few good weather days predicted preceding a cold front we felt something big could potential take place.
Still we were not quite prepared for a record breaking day that lay ahead.
Immediately on arrival a number of events were in progress and this did not stop the entire morning. At one time we witnessed 5 separate events going on within seconds of each other and more than once we had 3 events simultaneously.
By the end of the morning we recorded 45 separate natural predatory events between a Great white shark and a cape fur seal.
Without actually being here and seeing this it is difficult to describe what it is like to be part of a natural history event such as this. I know I went into complete sensory overload and not only where Chris & I exhausted by the end of it, but our crew and guests as well. It was very difficult to take it all in and to try and remember what exactly we saw.
This is now the highest number of events we have ever recorded in a morning at Seal Island. To try and comprehend how special this is I think I should point out that the next busiest Great white shark predatory spot is considered to be The Farrollon Islands off San Francisco. Scientists here record in the region of 40 events per season. That’s per season, not per day, week or month!
Of course the sharks here are feeding on much larger Northern Elephant seals, and the intense hunting behavior that we witnessed on this morning was something unique.
So, naturally some would ask what made this morning so special. We believe that a number of crucial factors all came together. There was a very high concentration of great white sharks at Seal Island at the time and as there was an approaching cold front a large number of young cape fur seals were returning back to Seal Island, giving the sharks plenty of opportunity.
The sea conditions were perfect flat with a lot of sunlight so this made spotting the events from our point of view a lot easier and although we did miss some events I think we were close to being accurate, if only under recording by a few.
I also think that with a high number of sharks present in a relatively small area the competition for food must be extremely high and this may force the sharks to hunt at any given opportunity, whether their chances of success are fair or not.
You might also wonder about 5 events taking place at one time. Again, just our opinion on this is that the sharks rely heavily on sound and vibration to pick up on the seals.
A small group of seals may be attacked by one shark and consequently be split up. The noise from this initial attack will attract other sharks to this area that will then in turn most likely pick up on the other seals. Often these simultaneous events happen close to each other and I think this further strengthens the above argument.
Well, science and my opinions aside...this was an incredible natural history event that I was very privileged to witness and all present on the boat that day admired and respected both shark and seal in a brutal battle for survival.