Apex Celebrates 2000th Trip Milestone
Posted on Saturday, 15 February 2014
It all began on a wintery day back in August 1996 when Chris witnessed his first ever breaching Great White Shark at Seal Island. Nearly eighteen years ago he would not have guessed at the wildlife history that would take place around this tiny 400m long Island located in the middle of False Bay and a mere five kilometres from the closest beach. Seal Island was to become one of the most famous places on earth for Great White sharks, their specular breaching behaviour and the most intense spot in the world for Great White shark predatory behaviour.
As we approach our 2000th trip to Seal Island I thought it would be a great opportunity to reflect on some interesting facts and highlights from the last eighteen years. Chris has kept data from day one at Seal Island and our crew and team continue this routine even when we are not at sea. Daily climatic and environmental conditions are recorded, comprehensive data points are noted for each predatory event and shark identification info is recorded for any shark that comes up to White Pointer 2.
At the end of the 2013 shark season we reached a grand total of 9,071 predatory events by Great White sharks on Cape Fur seals. This is truly a remarkable data set and the most comprehensive in the world for Great White shark natural predation.
The overall success rate of the sharks is now at 47%, but interestingly there is a noticeable decline in success over the past five years and this is down from 51%. Our most intense predatory day took place on 4 August 2012 where a total of 47 events were recorded over a five hour period.
The largest shark was seen in June 1997 and was conservatively estimated at a truly massive 6m.
Historically January to April was considered low season months but in the past three years we are suddenly seeing good numbers of sharks during this time. Perhaps this is due to lack of normal summer food availability such as small shark species which previously were abundant. The sharks are thus having to come back to the island earlier as their normal food inshore is too scarce.
Our data clearly shows gender segregation in certain areas around the island and the really large sharks seem most common between April and early June.
The average size of the sharks we have seen remains 3.4m down just slightly from the 3.55m for the first ten years. Approximately 10% of all sharks we saw between 1996 and 2005 were 4.0m or more, and today this figure is about 7.5%. We are seeing fewer sharks per trip for the past eight years than we did in the first ten years. This might also be due to the fact that we spend more time now focusing on natural predation.