doc_text: U.S. tour operators are planning to send a record 4,000 or more travelers to Antarctica, prompting calls for strict government regulation to protect penguins, other wildlife and the very fate of the frozen continent.
  "The number of tourists visiting Antarctica has more than tripled in the past five years," said Bruce Manheim, a Washington activist of the Environmental Defense Fund who calls existing controls inadequate.
  Antarctica has become a "hot" travel destination for the 1990s, beckoning older Americans seeking more adventure than Europe and hoping to see a fragile frontierland visited by only a privileged few in their youth.
  They are fueling fresh growth in the adventure travel industry, an estimated $1.3 billion-a-year phenomenon.
  About 800 American tourists traveled to Antarctica in 1988, 3,000 in 1989, and tour operators expect at least 4,000 in the December-February summer season.
  Manheim says it could reach 5,000.
  "There's clearly a trend toward these type of expeditionary visits to remote places in the world," said Manheim.
  He filed an appeal Tuesday with the government urging more regulation.
  "We are not trying to prohibit tourists from going to Antarctica, we just think tourism is something that has to be regulated carefully," he said.
  Concern began mounting after the January 1989 grounding of the Argentine naval ship Bahia Paraiso in which an estimated 175,000 gallons leaked into marine habitats, killing seals, penguins and other marine life.
  The vessel remains at the site off Palmer Station with some oil in its tanks.
  Particularly worrisome to critics are the plans of Ocean Cruise Lines of Fort Lauderdale to send the largest cruise ship in years to Antarctica, the 460-passenger Ocean Princess.
  Rates begin at $3,895 per person for a double-occupancy cabin on its three wine-and-caviar cruises, which are selling briskly.
  The first round trip from Buenos Aires, Argentina, begins Dec. 22.
  Manheim's appeal is urging the government to place strict controls on helicopter flights near wildlife sites, guidelines on tourist observation of penguins and seals, and coordination of cruise ship visits to breeding grounds.
  He said ships had made repeated tourist visits to the same wildlife sites, disrupting the breeding of seals, penguins and other birds.
  "A year after Antarctica's most significant environmental disaster, we still don't have regulations to prevent similar catastrophes," said Manheim.
  The U.S. government responds that effective regulations are already in place.
  "We have tried, and we believed we have dealt succesfully with the explosion of Antarctica tourism," said Jack Talmadge of the National Science Foundation, which regulates U.S. activities in Antarctica.
  Talmadge said the NSF has issued tourist regulations, established a mechanism for assessing fines for violations and taken steps to limit visits to U.S. research stations.
  He said the tour operators are also cooperating with the NSF to minimize the impact of tourism, including giving advance notice of ship visits.
  Although 16 nations fly flags in Antactica and seven claim slices of it, no nation holds title to the continent, which is larger than the United States and Mexico combined.
  Military flights and small ships carrying about 100 tourists have been frequent modes of travel to Antarctica since the first tourists visited in 1958.
  Now, the Chilean government has opened a spartan hotel at its Teniente Marsh Station on King George island, and LanChile airlines began commercial flights to that Antarctic stop last year.
  Australian entrepreneurs have proposed a five-story hotel, airstrip and hovercraft dock.
  The Canada-based Adventure Network currently flies tourists to one South Pole station.
  But the bulk of the tourists are Americans brought in by U.S.-based operators.
  Conservationists say the United States should therefore take the lead in adopting a model regulatory policy.
  "Antarctica tourism originates almost exclusively in the United States, and therefore we have the responsibility to regulate our tourism if we are to push for regulation at an international level," said Manheim.
  Operators of the Ocean Cruise Lines said there is no cause for alarm.
  "The tourist visiting Antarctica is a determined environmentalist, an avid lover of wildlife, and I can assure you that no tourist _ not one _ has hurt or killed a bird or animal," said Lars Eric Lindblad, an Antarctic travel pioneer who will lecture aboard the Ocean Princess.
  James Barnes, with Friends of the Earth in Washington, concludes that the travelers may leave their footprints, but they often return home more committed environmentalists _
  "Ambassadors of Antarctica."
  Nonetheless, he said, "The scale of these activities is growing at such a pace that it does provide cause for concern."
summary_text: "The number of tourist visiting Antarctica has more than tripled in the past five years," said Bruce Manheim, a Washington activist with the Environmental Defense Fund who calls existing controls to protect Antarctic wildlife inadequate.
  Manheim's appeal seeks strict controls on helicopter flights near wildlife sites, guidelines on tourist observation of wildlife, and coordination of cruise ship visits to breeding grounds.
  Because most tourists to Antarctica are Americans, conservations believe the U.S. should take the lead in adopting a model regulatory policy.
  The U.S. government responds that effective regulations are already in place.
  The National Science Foundation regulates U.S. activities in Antarctica.