Posted 20 August 2008 - 05:40 AM
As with most sharks, the sixgills present more of a thrill than a threat. The species is not known to attack humans, but their size (up to 15ft) and varied diet suggest that they should be treated with caution. Obviously, when you introduce bait into the equation – as was the case with our dives – the shark's behaviour shifts up a gear. In this case, the sharks became extremely bold and inquisitive; the larger individuals were completely unafraid of divers and tried to enter the cage. The Hydrus team has gone to extraordinary lengths to make this a safe encounter, but warns divers that in a few cases the cage has taken some punishment.
From my own experience, one of the most surprising physical aspects of this shark is its flexibility: its movement through the water is serpentine, and they have an ability to turn round 180 degrees in a speedy, fluid lunge. Tweaking their tails would be a really bad idea.
Interestingly, the related broadnose sevengill shark Notorhynchus cepedianus has been known to behave aggressively toward humans in unprovoked scenarios, and human remains have been found inside one specimen. As for the sixgills, they are iconic ambassadors for the deep water environment, and I consider it a rare privilege to have observed them in relatively shallow water.