A hi-tech study, largely conducted in Bermuda, is shedding new light on the behavioural patterns of Atlantic marlins while providing key evidence to promote conservation of the majestic billfish worldwide.

Both white and blue marlin numbers have plummeted in the Atlantic largely as a result of accidental kills at the hands of long-line commercial fishing equipment intended for tuna and swordfish, said Fisheries officer Dr. Brian Luckhurst.

As marlin have little commercial value in the Western world, the fish were dying needlessly at near critical rates.

These rates will have to be slashed by 60 percent to halt the decline of stocks according to scientists.

But conservation efforts were given considerable boost by findings from a ongoing study Dr. Luckhurst is conducting in conjunction with two American scientists - Dr. John Graves and Dr. Eric Prince.

Working in the waters off Bermuda since 1999, the scientists found that eight of nine blue marlin accidentally caught can survive if unhooked from the equipment and released.

The scientists used a satellite tagging system to track the progress of marlin caught and released with the help of a number of local fishermen.

In addition to the encouragingly high survival rate, the study found the marlin shot off in variety of directions and travelled 167 kilometres on average within five days of being hooked off Bermuda.

Dr. Luckhurst explained that the satellite tags - used for the first time ever on marlin during the study - were computer programmed to drop off the fish after five days.

Attached to high-density foam buoys, the tags rise to the surface of the water and then transmit information to the scientists via passing satellites.

Within 24 hours of the tag "popping-up" to the surface, the scientists received data on geographical location, water depth and temperature in their e-mail accounts.

The data has been ground-breaking as previously marlin had only been tracked acoustically - a method plagued by limitations.

Since the initial study, the scientists have increased the numbers of marlin tagged each year and extended the time lag before the tags detach from the fish, Dr. Luckhurst said.

Last year, 22 blue marlin were tracked with the satellite tags which cost between $3,500 and $4,000 each.

The fish have demonstrated similarly high survival rates after being hooked and travel up to 1,400 miles within 30 to 40 days of release.

Even foul-hooked marlin (when the hook is embedded in an area other than the jaw) and those that required resuscitation showed encouraging survival rates, according to the research.

Dr. Luckhurst said this is one of the most important findings from the study. "These are pretty tough fish," he said. "They are able to withstand a fair amount of abuse."

Fishermen who inadvertently hook marlin and find the fish are bleeding, should still release the fish, Dr. Luckhurst said.

"If you see blood, release it anyway," he said. "We now have well documented evidence the fish can survive."

The scientists published their original findings in the journal Fishery Bulletin and a follow up article is planned for later this year.

One of the biggest surprises has been the distances the marlins travel and the manner they disperse in all directions.

"We really had no idea," Dr. Luckhurst said. "They are going all over the ocean. It is really extraordinary."

In addition to providing key evidence to support conservation, the study also has important economic spin-offs to the sport fishing industries in Bermuda, the United States and the Caribbean.

"It generates enormous amounts of money into the economies of countries which offer (sport fishing)," Dr. Luckhurst said.

Preserving the stocks of marlin will keep the industry alive for years to come.

Dr. Luckhurst said Bermuda now has about a 95 percent release rate for marlin and the conservation ethic has become the norm in local waters.

Since the initial study, 31 countries have signed on to a convention for mandatory release of marlins.

The mandate is to remain in place until 2005 and it is hoped it will reduce landings of blue marlin by 50 percent.