I would hazard a guess and say since the 1960's and 70's the Australian population has grown almost double. This could simply mean there is a lot more people in the water all around Australia and a lot more of them have boats now. A lot more people travel to the more remote dive locations and their is a lot more noise and urine in the water at the local beaches now. There are a lot of surf spots I don't frequent now because the crowds are just huge.
