Three women donned scuba masks and jumped into the waters off Oahu's North Shore, floating inside a submerged cage as about a dozen sharks glided toward bloody fish scraps tossed into the water by a tour company.
Tourist Kim Duniec said the experience of coming eye-to-eye with sharks was exhilarating. "Their eyes were scary, but they were still graceful, absolutely beautiful," the Beaver Dam, Wis., woman said.
Shark tours like this have become a popular visitor attraction in Hawaii, but a movement is gaining momentum to shut them down.
Some Native Hawaiians consider sharks to be ancestral gods and view feeding them for entertainment to be disrespectful of their culture. Surfers and environmentalists fear the tours will teach sharks to associate people with food — leading to an increase in attacks — while disrupting the ocean's ecological balance. Federal fisheries regulators, meanwhile, are investigating the tours on the grounds that they are illegally feeding sharks.
The anti-shark tour movement ignited when residents noticed a large metal cage mounted on a boat at a marina in front of a popular Hawaii Kai restaurant in March. They remembered Oahu's two shark tours used similar contraptions on the North Shore. The location of the tours helped fuel the opposition — Hawaii Kai is an affluent bedroom community on the other side of Oahu.
Within weeks, some 400 residents overwhelmingly hostile to shark tours, jammed a local elementary school cafeteria for a town hall meeting. State lawmakers left vowing to draft legislation to shut down the tours. State and federal regulators asked those present to report suspected violations of shark feeding rules. The shark tour on Hawaii Kai soon shut down, but the others remain.
Randy Honebrink, a shark expert with Hawaii's Aquatic Resources Division, said the state has always opposed the tours out of the concern they may prompt sharks to start linking humans with food.
But there are also broader potential environmental hazards, especially because sharks sit at the top of the food chain.
George Burgess, a University of Florida shark researcher, said shark populations are likely to increase in areas where tours feed sharks daily. An inflated shark population might consume more prey, depleting other marine life, Burgess said. Or a tour site may lure so many sharks that apex predators may decline in other areas.
Among many Native Hawaiians, the issue is primarily about honoring their culture.
Sharks are featured prominently in Hawaiian folklore, and have played a major role in the lives of Native Hawaiians for centuries.
Some Hawaiian families eat sharks. Others believe their ancestors appear as sharks, chasing fish into nets or guiding canoes safely back to shore. In these cases, sharks are considered ancestral gods, or aumakua, and people give them offerings of bananas and awa, a drink.
"The disrespect of the aumakua, that's what hurts us the most," said Leighton Tseu, a Native Hawaiian who considers sharks ancestral gods.
Other coastal communities around the world have struggled with shark tours as well.
Environmentalists have criticized South African cage-diving tours that lure great white sharks with bait. In the Bahamas last year, a shark fatally bit an Australian tourist on a tour that didn't use cages or protective gear.
Florida bans shark feeding in state waters, as does Hawaii.
Federal law — which governs waters between 3 miles to 200 miles from the coast — prohibits feeding sharks off Hawaii and Pacific island territories like American Samoa. Exceptions are made if fishermen are baiting sharks to harvest them or if the feeding is part of government-funded research.
Michael Tosatto, deputy regional administrator for the National Marine Fisheries Service in Honolulu, said his agency has launched a probe into Oahu's two tours.
"I can't necessarily give you a lot of details about ongoing investigations other than to say that yes, we are investigating these companies and how they operate, and again, hope to address the violations that they're committing," Tosatto said.
Joe Pavsek, owner of Hawaii's original shark tour, North Shore Shark Adventures, said his operation is legal.
"If you read the law, you'll understand that I'm not breaking any laws," he said in an interview. He didn't offer further explanation.
The former private investigator said he started his tour in 2001 after two decades of taking friends and family to see sharks off Haleiwa.
A rival company, Hawaii Shark Encounters, started several years later in the same area off Oahu's North Shore. The mostly rural district is popular with big wave surfers and tourists who drive up from Waikiki to watch green sea turtles lounging on the beach.
Pavsek said his tours take people to waters where crab fishermen have unintentionally been attracting sharks for 40 years by tossing unused bait overboard.
"We don't have to feed the sharks if we don't want to. We do it for the customers," Pavsek said.
Pavsek said the tours aren't altering shark behavior, citing research by Carl Meyer, a Hawaii Institute of Marine Biology scientist, who says sharks at North Shore tour site maintain their seasonal breeding and migration cycles. The sharks aren't permanently attached to the feeding site, Meyer said in a recent presentation to state lawmakers.
Meyer's research also shows most sharks at the Haleiwa site are of the Galapagos and sandbar variety, species rarely documented as having attacked humans. Tiger sharks, which are responsible for a large share of Hawaii shark attacks, account for 2 percent of the tour site's sharks.