Sharks under siege
Scientists, sport divers at Farallones disagree on how much human attention great whites can stand while feeding
Monday, May 7, 2001
 
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Sport diving has become so popular in the Gulf of the Farallones National Marine Sanctuary that scientists are complaining that gawking tourists are scaring sharks away, undermining crucial research.
A local adventure recreation company started offering "cage dives" in the sanctuary about three years ago, luring customers with the promise of close-up views of great white sharks at their daily routines of devouring sea lions and seals.
The peak of the season is in late summer and early fall, when the sharks patrol elephant seal and sea lion rookeries at the Farallon Islands. Boatloads of five or six divers - each paying close to $1,000 for a full-day trip - haunt the islands, submerging in protective cages once a kill is under way.
But scientists are taking a dim view of the diving adventures, saying they muck up sensitive research projects. Some shark researchers plan to petition sanctuary managers to impose tough controls on sport dives.
"They're bad news," said Scot Anderson, a field biologist with the Point Reyes Bird Observatory who has been conducting field studies on Farallones sharks for 13 years.
"Last year they completely disrupted our research," said Anderson. "Out of seven feeding events, they drove away sharks on three of them. They were out there between 20 and 30 days last year, and it's really inhibiting our work."
During the past 15 years, researchers have developed new techniques for attracting, videotaping and monitoring the region's relatively abundant sharks - including use of surfboard-size lures and special telemetry tags that relay data on the sharks' behavior and migratory patterns.
The work has helped change perceptions of the formidable ocean predators.
They are not, it turns out, insensate organic killing machines. Rather, they're sophisticated hunters that are supremely aware of their environment, employing subtle strategies to capture their preferred prey.
Shark researchers say their work is sensitive to disruption, particularly when a "feeding event" is under way. That's when great whites kill and eat marine mammals, displays that are both visually spectacular and a source of invaluable data.
The companies that offer the dives object to being portrayed as despoilers, saying they are sensitive to both the requirements of the research teams and the physical well-being of the sharks.
They intend to continue offering diving trips to the Farallones, they say, arguing that they have a legal right to do so. Also, they maintain, the tourist business ultimately increases environmental awareness by providing average people the opportunity to see the ocean's fiercest piscine predator in its natural realm.
"We are not driving the sharks away," said Lawrence Groth, the owner of Golden Gate Expeditions, a company that co-sponsors the Farallones dives with San Francisco's Absolute Adventures.
"The sharks come up to my boat," said Groth. "We tried to give Scot every opportunity to talk to us last year, to say, ÔThis is what I'm doing, so please do what you're doing a little different.' He ignored me the entire season."
Bruce Watkins, a diver and underwater photographer who has accompanied Groth to the Farallones, said divers have no more impact on the sharks than the scientists.
"I once saw (the scientists) respond to a feeding event at a high rate of speed and they actually hit the shark," said Watkins. "But the shark kept right on feeding. (Sport divers) should be able to film the events the scientists are researching. The two activities are compatible."
Point Reyes Bird Observatory biologist Peter Pyle, who has led the shark research project at the Farallones, said the scientists go out of their way to keep their distance.
"We do everything to ensure that we are not harming or disturbing the sharks," he said. "Our study is well-known for the lack of chumming and other activities that may change the behavior of sharks."
Pyle said he is not attempting to put anyone out of business. But he said researchers are concerned that recent success by Groth and his partners might attract more commercial operators, "creating an environment that is harmful to the sharks and that will prohibit us from continuing meaningful research."
Pyle said he will insist on enforcement of two sanctuary regulations that apply to recreational divers: a prohibition against floating decoys without a permit from the California Department of Fish and Game, and a requirement that boats stay 100 meters from any vessel displaying a research symbol, three black balls in a triangle.
In the past, sport divers have used surfboard decoys to lure sharks, and have closely approached feeding events monitored by scientists.
Sean Van Sommeran, executive director of the Pelagic Shark Research Foundation, a Santa Cruz organization that contributes to shark studies around A-o Nuevo Island, said researchers aren't opposed to recreational viewing.
"The Oceanic Society has been conducting educational, noncommercial viewing trips for years, and that's fine," said Van Sommeran, who recently hosted a discussion of the issue under the auspices of the Gulf of the Farallones National Marine Sanctuary.
"What we are concerned about is the unrestricted pursuit and approach of sharks during predatory events," said Van Sommeran. "Great white sharks are a protected species under state law, the animals they feed on are federally protected, and the Gulf of the Farallones is a designated sanctuary. We're simply urging the implementation of guidelines and standards of conduct."
Watkins said the researchers are upset because "they've had (the Farallones) to themselves for so long, it's kind of like their private playground. They've enjoyed an exclusive monopoly on the filming (of great white shark feeding events), and they don't want to give that up."
The issue will be resolved one way or the other in a coming sanctuary management plan review.
Ed Ueber, the manager for the Farallones sanctuary, the adjacent Cordell Bank National Marine Sanctuary and the northern half of the Monterey Bay Marine Sanctuary, said the review will include public input and scientific testimony.
A new management plan for the Farallones should be in place by the end of 2003, said Ueber. It may or may not ban recreational cage diving, depending on the findings of sanctuary staffers.
"The comments we have heard indicate (the divers) may be interfering with research needed to protect great white sharks," said Ueber. "We will have to consider that - but until the evidence is collected, they can keep diving out there, as long as they don't violate current rules."
E-mail Glen Martin at glenmartin@sfchronicle.com.