Hi Folk.
Thanks for thinking about the problem...............
You ask if some research has been done, well
The Marine Living Resources Act was written by some bright fellows, and the law requires a 300m radius (unless of course you obtain a permit which allows you to get closer)
I said that over the past 7 years - read that again, 7 years - I have been, together with FF and numerous instructors who have worked for us, proven without a question of doubt, that all whales we have harassed by orbiting for too long or by orbiting too low, have gone 'tail up, together with their calves and mid-wives', and gone deep, really deep, not to surface for as long as we have cared to remain and wait.
Dolphins on the other hand, who swim gracefully, get all panicky and dart all over each other in a frantic effort to get away from the microlight shadow. If the shadow does not pass over the school, then they just all dive down, usually at the signal of one or two of them, who 'slap' the water with their tail. They also remain deep for a long, long time before re-surfacing.
Some dolphin school do not seem to mind, whereas others go crazy in their effort to 'escape'.
I have never known dolphins to mind a boat. They actually come alongside and swim in the bow-wave. The dolphin watching rubber-duck actually just parks beyond backline sometimes, and waits for the dolphins. They come to the boat.
So it is safe to assume that it is not the sound that bothers them. It has something to do with this huge creature passing overhead.
So, I feel qualified to make the statements I have, based on my observations over the past 7 years and thousands of tourist flights I have
personally made along this stretch of coastline.
The reason I made these observations, was because the director of the Marine Living Resources personally phoned me and asked for my help in bringing the above mentioned behaviour of these mammals to the attention of local pilots.
The total number of Whales on our eastern coast does not seem to have diminished, only the number coming back to the coastline between Umhlanga Rocks and Tinley Manor. There are still hundreds of whales giving birth along the Transkei Coast, and further North. They have just stopped coming here.
I do not know the answer, but given the above observations over the past 7 years, I would say to anyone asking "Go figure".
If my style of writing seems aggressive, I am sorry. I do not mean to come across that way.
Just trying to share my views with the readers..............