Jimmy Hall’s controversial shark tour company,
Hawai’i Shark Encounters, charges $100 per person,
and takes passengers of any age and dive experience.
Boats leave Oahu’s North Shore daily and cruise three
miles out of state water boundaries. The crew loads
“victims,” as they’re jokingly called, into cages with
Plexiglas windows and as many as 30 sharks come to
swim around them. Hall’s website says sharks are drawn
to the surface by the sound of the boat engine—but
he doesn’t mention that the main attraction is the fish
scraps regularly used as chum.
Critics say chumming attracts the predators close to
  shore, scaring beachgoers and changing sharks’ innate
  behavior. An advisory panel that oversees fishing in
  federal waters around Hawai’i approved a proposal last
  October that would ban shark feeding by commercial
  tour operators.  
Operators like Hall moved three miles out into federal
  waters when Hawai’i had passed similar measures
  for state waters after people complained about seeing
  sharks on the North Shore. But residents got more up
  in arms when they heard that Hall planned to expand
  his fleet from four to six boats. Now the fishing advisory
  panel is considering banning shark feeding in all
  federal waters from three to 200 miles off Hawai’i, but
  there is the question whether it has jurisdiction over
  shark-viewing tourists. One of its senior scientists said it may take “several years” before the council can come
up with a recommendation because of the cost and
amount of research involved.
Shark expert John Naughton, a marine biologist
  with National Oceanic and Atmospheric
  Administration, doubts sharks follow boats back to
  shore since they can’t keep up for long at speeds of
  20 miles an hour. “They may follow the boats for a
  while but then they’ll just drift off and go back to their
  normal haunts,” he told a Hawaii TV news station last
  summer. Naughton studied Hall’s shark operation and
  believes it uses no more chum than the average fisherman.
  He also said sharks are not being conditioned
  to swim towards land, only to Hall’s boat, and that the
  increased shark sightings is because there are more
  sharks and more people in the water to see them.  
However, other scientists and fishing industry members
  warn of tours’ impact on sharks and their habitat.
  “The animals are going to be affected in the sense that
  their behavior is going to be changed,” said Robert
  Hueter, director of Mote Marine Laboratory’s Center
  for Shark Research in Sarasota, Florida. He thinks tours
  can also cause health hazards because bringing sharks
  together in abnormal densities could spread pathogens
  and infections. But he is not opposed to shark diving per
  se. “As long as tours are well controlled and show concern
  for the animals, it should help fuel shark conservation.”