Feeding takes two distinct forms. They may chase and hunt their prey or simply clean up dead fish in the form of carrion. It's not recommended for divers to be close when sharks are hunting frenetically. Things get a bit out of hand but when sharks sense there is carrion to be had they are less rushed and far less competitive.
Some years ago I was on an extended trip on a liveaboard dive boat down in the Sudan. All the passengers excitedly talked about the prospect of seeing sharks but as the trip developed it was obvious that there was a distinct possibility they were going to be disappointed. When we got to Sh'ab Rumi, a reef famous for shark encounters, they were equally saddened to come back from the first dive without a shark sighting.
I determined to do something about it. During the second dive, about six or so grey reef sharks swam round us in a relaxed manner. All the passengers were thrilled and returned to the boat excitedly talking about the experience. On the third dive some of them noticed what I had done and later complained to the captain. They protested that I was feeding the sharks.
Not actually feeding them, I had taken with me on the dive a screw-top jar with a bit of dead fish inside it. From time to time I released some of the dead fish smell into the current to lure the sharks up from the depths.
During the heated debate that followed I asked them if they wanted to see sharks or not and explained that the sharks were not going to turn up out of curiosity for air-bubbling divers but might be drawn by the idea of a risk-free meal as represented the smell of a dead fish.
The fact of the matter is that whenever you see any close-up photograph or television footage of sharks it has been achieved with the help of some bait. Different species of shark have different diets. Reef sharks eat reef fish whereas pelagic sharks eat pelagic prey. Great hammerheads for example feed on stingrays they hunt for hiding buried under the sand. It's no good offering the wrong bait.
There are organized shark-feed dives in many different parts of the world, particularly in the Bahamas, Cuba, Fiji and French Polynesia. People pay a lot of money to witness a shark feeder doing his job and in turn get in close proximity to these otherwise discreet predators. Sharks live a long time and are careful what they eat. They are also careful not to damage each other during these feeds. They know the difference between the opportunity to eat carrion and the competitive nature needed when hunting live prey. I have photographed many different species of shark with the aid of a local expert who knows what particular bait to offer.
Nevertheless there are those within the diving fraternity that are vehemently opposed to the idea of staged feeds. They believe that it teaches sharks to associate people with food although statistics prove otherwise. One dive centre in the Bahamas has seen more than 60,000 people enjoy the spectacle without a single client getting injured while holidaymakers frequent the water off those beaches without any ill effect.
People might tell you they had a close encounter with an oceanic white-tip shark without the aid of bait when in fact they were the bait. Oceanic white-tips are ocean-roving scavengers that cruise the oceans perpetually seeking a meal. They investigate anything floating at or near the surface and they approach divers simply to find out if they would make easy pickings, turning away when they decide they will not.
These animals have learned to follow freighters along the busy sea-lanes of the Red Sea because the galley waste is usually tossed off the stern of these ships. Big liveaboards make the same sorts of sounds with their engines and generators and the same tantalizing splashing sounds coming from the sterns ring the dinner bell for the sharks at dive sites where deep open water abuts the reef. These sharks are in feeding mode.
Take it from me, if you want a shark to get close enough to you for a good photograph, food or the promise of a free meal will need to be involved!