While in Port Lincoln I partook in the cage dives with the great whites that they do 5 hrs boat ride out in the islands there. It was interesting talking to the boat tour operators that have been there for decades and their take of the shark issues (this was three years ago), this is what they said when quizzed about the boom in population....
- In the 80's the white sharks were protected with out an actual population survey being done to establish if they were endangered/threatened/etc.
- The great whites need to be 5m long to breed and that happens at about 20 years of age. The initially protected sharks are breeding for the past 15 years and the baby sharks from those protected ones are now breeding (compounding interest any one?)
- They used to think the sharks needed to eat a mammal a week to maintain metabolic activity. They now know by tracking tagged sharks that they will do a loop from the Neptune Islands in south aust, to perth, to exmouth, back to perth, across to south Africa, back to Neptune Islands in south aust. They do that loop TWICE PER YEAR and need to eat a mammal a day to keep that level of metabolic activity. So that is a seal (who's food is being over fished) or another mammal.
- Over the 20 years they had operated it went from one boat taking half hour to get a shark on the boat to 5 boats with 5 sharks on it before the anchor hits the ground. Perhaps they are training sharks to interact with people or perhaps the sharks food is dwindling and they are hungry as F.
I never agreed with the shark diving tours but figured if they were shut down I would like to of tried it. I had hoped that when the sharks attacked the cage you would have some prewarning that a freight train with teeth was about to hit you but above the surface, not a ripple. You'd lose your leg before you could brown ink your self to get away. I had also hoped they would be beautiful intelligent high order predators like when I've swam with hammer heads however they were like big dumb cows thrashing about with their mouth open to take anything that stayed in its path.
I certainly haven't been diving in the past few years and honestly when we had a rope around one of the props on the boat last I wasn't the first one to volunteer to dive under the boat to cut the rope away.