Hamburg, Oct 22 (DPA) The Antarctic wilderness is attracting a growing number of tourists keen to experience the icy landscape, yet their presence is posing new risks to this unique marine environment.In 1992 around 6,000 nature-lovers made the long journey south. But the number rose to 46,000 last season - a clear sign of the boom in travel to the area surrounding the South Pole: It also marks an increase in the number of shipping operators offering cruises to the Antarctic peninsula during the five-month period from November to March.

The region which was once almost the sole preserve of research ships, is experiencing an onslaught of tourists and there have been calls for new guidelines which would impose more stringent controls on the number of vessels visiting.

The voluntary International Association of Antarctica Tour Operators (IAATO), which was set up in 1991, has already stipulated how many ships a year will visit the peninsula and where they must dock.

The aim is to limit the adverse impact on the environment by ensuring that remote bays are not besieged by too many boats on a given day. Tour organisers are required to give prior notice of visits and no more than 100 passengers at a time are allowed to set foot on the continent at any given landing. They are permitted to stay for a maximum of four hours before resuming their onward voyage.

The IAATO issued permission last season to 61 cruise ships or to nearly twice as many as five years ago when 35 such permits were issued.

“Most of the ships opt sensibly for the ice-free passage,” said Johannes Zurnieden, who is deputy president of the German Travel Federation (DRV) in Berlin. As managing director of a Bonn-based travel company, Phoenix Reisen, he also has a personal stake in the tourism business. Most of the vessels visit the northern part of the peninsula “and that is enough to get the flavour of the Antarctic,” maintains the expert.

Vessels with more than 500 passengers on board are prohibited from landing, something which should be borne in mind by those eager to sample the genuine atmosphere of an Antarctic expedition.

Princess Cruises currently deploys the largest ships in the Antarctic. Last year, the Golden Princess with 2,600 passengers and 1,100 crew was underway on sightseeing trips in the region and this year the voyages will be staged using its sister ship, the Star Princess.

Bearing in mind the regulations, travellers on these ships would be well-advised to take along a high-powered telescope if they want to take in the grandeur of the landscape.

“When it comes to tonnage there is a degree of insensibility,” said Sebastian Ahrens, managing director of Hapag-Lloyd Cruises in Hamburg. Hapag-Lloyd helped set up the IAATO but would now prefer operators to be strictly regulated rather than rely on voluntary compliance.

“If you cruise along certain parts of the Norwegian coast, the authorities keep a very close watch, but for the Antarctic no clearly defined rules apply.”

The strain on the delicate ecosystems of the Antarctic grows with every visitor who sets foot on the territory even though the guidelines are usually adhered to. The shoes of visitors are disinfected before and after they land and they are obliged to maintain a distance of least five metres to penguins and other animals.

Under the IAATO code of conduct, ships visiting Antarctica must be powered by diesel rather than the heavy fuel oils normally used by many vessels and water and waste may not be discharged into Antarctic waters.

“These criteria represent absolute minimum standards which must be enforced in the area,” said Caroline Schacht of the Worldwide Fund for Nature (WWF) in Hamburg. “Unfortunately, far too many shipping lines have not signed the treaty,” said the marine biologist.

Many of the cruise ships deployed in the Antarctic have no ice-strengthening and this can minimise the enjoyment for passengers whose captains decide to play things safe. “As soon as there is any ice around, the vessels without ice-strengthened hulls move out quickly,” said Benjamin Krumpen of Phoenix Reisen.

Only the genuine icebreakers can venture further, ships like the polar-class icebreaker Kapitan Khlebnikov which was built in Finland in 1981 to survive the rigours of northern Siberia.

The potential dangers of a cruise in the world’s most southerly waters were highlighted by the fate of the Canadian cruise ship Explorer which sank last winter 15 hours after colliding with an iceberg 1,000 km from Cape Horn. Another vessel came to the aid of the stricken tourist ship and both passengers and crew were winched to safety.

A number of shipping lines have already reacted to the Antarctic overcrowding. Norway’s Hurtigruten is sending the MS Fram to the penguins for 2008/09 but not its sister ship MS Nordnorge. Speaking in Hamburg, the company’s managing director Bernd Stolzenberg said the move was in response to the “increasingly difficult Antarctic market.”