The popularity of cage diving and swimming with sharks is at the focus of a booming tourist industry. A common practice is to chum the water with pieces of fish to attract the sharks. These practices may make sharks more accustomed to people in their environment and to associate human activity with food; a potentially dangerous situation. By drawing bait on a wire towards the cage, tour operators lure the shark to the cage, possibly striking it, exacerbating this problem. Other operators draw the bait away from the cage, causing the shark to swim past the divers. At present, hang baits are illegal off Isla Guadalupe and reputable dive operators do not use them. Operators in South Africa and Australia continue to use hang baits and pinniped decoys. In South Australia, playing rock music recordings underwater, including the AC/DC album "Back in Black" has also been used experimentally to attract sharks. Companies object to being blamed for shark bite incidents, pointing out that lightning tends to strike humans more often than sharks bite humans. Their position is that further research needs to be done before banning practices such as chumming, which may alter natural behaviour. One compromise is to only use chum in areas where whites actively patrol anyway, well away from human leisure areas. Also, responsible dive operators do not feed sharks. Only sharks that are willing to scavenge follow the chum trail and if they find no food at the end then the shark soon swims off and does not associate chum with a meal. It has been suggested that government licensing strategies may help enforce these responsible tourism. The shark tourist industry has some financial leverage in conserving this animal. A single set of great white jaws can fetch up to £20,000. That is a fraction of the tourism value of a live shark; tourism is a more sustainable economic activity than shark fishing. For example, the dive industry in Gansbaai, South Africa consists of six boat operators with each boat guiding 30 people each day. With fees between £50 and £150 per person, a single live shark that visits each boat can create anywhere between £9,000 and £27,000 of revenue daily.