Although chumming is done with a natural food source, I still can't think of it as being natural.

IMHO, we're taking their natural food stuff and utilising it in an unnatural way. The scent path isn't coming from a dead carcass, it's coming from a bucket on the back of a boat. We're doing this to manipulate their actions so as we can get what we want from them, we use the chum to get them to perform on demand. So yes, whilst the food stuff we're using is natural, as is their reaction to it, the event itself is completely human generated to satisfy human wishes.

I spent a few months diving in French Polynesia, in both the tuamotous and society islands. Shark populations there are high, shark sightings happened on pretty much every dive. We encountered plenty of black reef tip and white tip reefs, along with black tips and greys and a scattering of others. Sharks would tend to be inquisitive but stand off'ish, ie. they'd check you out but keep a respectful distance. I then did a dive in Morea where sharks were regularly fed by dive centres (I say were, I believe the practice has now been banned in the Society Islands), the minute the boat stopped the sharks, black tip reef, white tips reef and black tips were there circling, we almost hit them as we got in the water, they were bugging us the whole way down. The same species of shark, displaying completely different characeteristics. Interestingly, when we dropped in the water away from the regular feeding site the sharks didn't pay us too much attention. Only one experience to base my viewpoint on, however it would imply that those sharks in the feeding area were showing a conditioned response.

Again, to make it clear, I'm not saying shark feeding should be banned, it is just not something I will support, either by going on one myself or by recommending it anyone else who cares to ask for my opinion.

Just as a foot note, I've been in the water with a wide variety of sharks and never felt threatened. However if I saw a dead whale carcass with sharks having a good munch, I think I would develop a very dibilatating case of hydrophobia