June 2010
The action picks up from where we left off last month with the winter sharks still coming thick and fast. The weather is definitely starting to feel a little more like winter in the early mornings, with the water temp holding at around 15 C (don’t worry we have 7mm thick wetsuits!) The underwater visibility also remains good. On most of our trips throughout June we have been able to see the rocky reef systems on the ocean floor that our White Sharks naturally patrol looking for a meal. We are seeing on average around 8 different sharks per trip. Nemo the shark we introduced you to last month seems to have migrated off for the time being as she hasn’t been sighted yet during the month of June. No doubt she will be back soon, as this shark when looking at our records is regularly sighted throughout the winter period. There is another shark in the area though that shares the same name as “Nemo” only the crew put the word “Big” before her name. Ladies and Gentlemen White Shark Projects would like to proudly introduce to one of our favourite sharks “Big Nemo”. She is one of the most easily identifiable sharks that we get in the area. She is a +/-3m female shark with her left pectoral fin completely missing and her dorsal fin has a great big whole right through the centre of it like a bullet hole. Big Nemo was originally tagged in Mossel Bay further up the East coast in 2003(according to a very reliable local scientific source). It is more than likely that at some point during her migration along the coast she either bit a baited hook and became entangled in a steel trace, or she got herself stuck in a net and had to power herself free. The result was that the research tag was ripped out from her dorsal and she lost her left pectoral fin. It greatly upsets the crew when we see any shark around the boat that has been damaged as a result of human interference. Big Nemo as the name suggests doesn’t seem to be significantly disadvantaged by the absence of her left pectoral. It would seem that she has adapted rather well as she continues to grow on average around +/- 30cm per year (which is the average growth rate for the majority of the great white sharks we observe). The pectoral fins purpose is similar to the wings you would find on a plane, they are also used to signal and communicate to other sharks. Next time you’re in a moving car (and it is safe to do so!) place your hand flat outside the window so there is minimal wind resistance against it. If you tilt your hand up the air pressure underneath your hand is greater than air pressure above it meaning you generate “lift” and your hand goes up. If you do the opposite and you tilt your hand down the pressure on top of your hand is greater than it is underneath it and you get “down force” and your hand goes down. The shark’s pectoral fins allow the animal to ascend and descend through the water column with that powerful tail providing the propulsion.

 Big Nemo’s behaviour around the boat does suggest that she has had to adapt her hunting/scavenging strategy. The majority of our sharks approach the bait and the boat in a calm, curious and inquisitive manor. Not Big Nemo though. Her tactic to hit the target in the water is to come from deep and as fast as possible often exploding out of the water allowing us to see her distinctive fins! Due to the hydrodynamic instability caused by the lack of her left pectoral fin, she has a tendency to “roll” to the right. It doesn’t matter how good the visibility is or how many spotters we have she always seems to decipher the puzzle and to be quicker than we are! On the 5^th of June she used the boat as cover, approaching in the opposite direction from the chum line and took the bait once again at full speed. Approximately 10 minutes passed whilst we were able to work with other sharks before Big Nemo returned and decided she wasn’t finished. This time she approached from the port bow again from deep and again at full speed exploding out of the water like a submarine, biting the bait before crashing back into the cold Southern Atlantic water. Phil Donolan  a bar owner from Queensland Australia was in the right place at the right time to catch this fantastic shot of Big Nemo.  As you can see from the photograph Big Nemo is rolling slightly to the right as she hits her target. No doubt she will continue to keep us on our toes as the month of June progresses!

On the 7^th of June we were running an exclusive trip for our White Shark Project Volunteers, we had anchored South of Geyser rock (which is home to our cape fur seals) as there was a mild 12 knot NW wind present, allowing us to use the island as cover to give better working conditions. We had a fantastic trip with 9 different sharks spotted ranging from 2.5m to 3m in length 7 of them being identified as male. The highlight of the trip however was the crew and the volunteers being able to observe our 1^st successful 100% natural predation of the winter 2010 season! As it was overcast Gerald our skipper was sat on the fly deck spotting for sharks giving the bait handler some much needed help when he shouted “PREDATION!!!!!” What followed next was 3 minutes of exhilarating action as the game of seal versus a 2.5-3m shark unfolded less than 30 m off the port stern! To even observe this from a distance is such luck! We fortunately were in the right place at the right time! It is always difficult to know who to support when you see a natural predation taking place. Half of you wants to see the seal escape and the other half wants you to see the most beautiful and efficient marine predator demonstrate how its finely evolved senses and physiology allow it to predate on such a difficult agile meal. The seal porpoised desperately in all directions. It firstly headed towards our boat before then trying to acrobatically jump in a different direction, trying anything to gain an advantage. One can only imagine the explosive game of cat and mouse that was taking place beneath the waves. The seal tried on at least 6 occasions to jump and make an incredibly tight turn, attempting to get on the tail of the pursuing hungry shark so that it could out manoeuvre its pursuer. One photo we captured you can see the white shark breaching with its jaw fully protruded missing the seal by inches! You can also see the seal is looking over its front right flipper in the direction of the gaping mouth knowing it is in a fight for its life, and above a seagull hangs ominously wondering if it too is about to get a meal. The predation continued with the seal still desperately trying out manoeuvre the shark, and then nothing. Nothing, no more white foam, no more shark bursting from the Ocean’s surface, no more seal coming up for air and porpoising. For around 30 seconds the action completely stopped. We assumed that the seal had managed to get away or that the shark had given up and gone elsewhere, all eyes were scanning the water, that was until our skipper Gerald stated “yeah the shark got him”. We could see roughly in the area the action had been taking place a large pool of crimson blood forming on the Ocean’s surface. The decisive hit must have taken place beneath the waves, as must the consumption of the seal. After a further few minutes the only evidence that a predation had taken place was the racket made by squabbling seagulls as they fought each other for scraps of seal. Shark  1-0 Seal.

13^th-15^th June. As with last month’s shark activity we had another cold front move through resulting in high wind speeds and swells of around 6m. As a result we did not go to sea, as our skippers do not under any circumstances take chances. The safety of our clients and the crew always come before taking people to go to see the beautiful great white sharks, as stated in last month’s shark activity we would rather cancel and have you come out with us when it is safe to do so!!