DATE: Monday, March 17, 1997                TAG: 9703170052

SECTION: FRONT                   PAGE: A1   EDITION: FINAL 

SOURCE: BY LANE DeGREGORY, STAFF WRITER 

                                            LENGTH:  158 lines

OUTER BANKS BLUEFIN LURE RESEARCHERS TAGS TRACK THE FAMED TUNA'S SWIMMING, SPAWNING PATTERNS.

During a 28-hour span, the 6-year-old bluefin tuna tagged just off Cape Hatteras dove 200 feet to the bottom of the sea, swam north near Diamond Shoals Light Tower, then made a beeline south to the wreck of the ironclad Monitor and ended up off the southern tip of Ocracoke Island.

The 6-foot-long, 230-pound fish covered about 60 miles in little over a day, the high-tech tag showed.

More than 120 bluefin are wearing the tags now as a result of a program designed to help scientists track their every turn.

The unprecedented tagging project conducted in the Atlantic off Hatteras Island this month is the largest research study ever made on one of the world's most sought-after fish.

Results of the $650,000 study could have international implications on how to manage the species.

Hundreds of anglers from around the world have arrived on the southern Outer Banks to hook some of the thousands of bluefin tuna that have been swimming along the Gulf Stream. They say it offers the most exciting fishing found anywhere.

The state-of-the-art tagging project has shone a global spotlight on usually sleepy Hatteras Island. Everyone from television icon Dan Rather to reporters from The New York Times, National Geographic and National Public Radio are scheduled to visit the isolated barrier island village this week to cover the tuna study. Hotels, restaurants and marinas that usually shut down for the winter are pulling in more profits this month than they did during peak tourist season last July.

``Bluefin tuna are a very political fish,'' said biologist Barbara Block, a Stanford University professor who is heading the tagging series. ``We've found a scientific mecca for bluefin tuna. It just happens to be off Cape Hatteras in the winter.''

Living up to 30 years, weighing as much as 1,500 pounds and growing more than 7 feet long, bluefin tuna are some of the largest fish found in any ocean - and can be the most lucrative catch in the world. A single fish sells for as much as $60,000 at Japanese sushi markets. And nations quarrel over quotas for protecting the coveted tuna.

Four winters ago, schools of bluefin began showing up off North Carolina's southern Outer Banks. Thousands of giant tuna were lingering between 10 and 20 miles offshore, biting at every bait tossed overboard. Charter boat captains, who usually tied their vessels to the docks from October through March, couldn't keep up with the offshore bookings.

Scientists soon headed to the isolated area. Last year, they implanted 10 tracking tags in giant bluefin tuna off Hatteras. This month, two dozen biologists, fish surgeons and fisheries management specialists from across the country have tagged another 110 tuna with three types of tracking devices.

They are trying to figure out where bluefin tuna swim, when and where they spawn and how deep they go. They say data gathered from a single tag could tell them more about the famous fish than the last century of research has yielded. If their work off the Outer Banks proves the same fish that swim along Carolina also make it to the Mediterranean, international allocations of bluefin tuna catches could be changed forever.

``We don't understand at all who these fish are or what they're doing here,'' tuna technician Doug Fudge said Thursday. ``They've only been here for a few short years. This huge population with strange behavior is showing up now in a place no one ever expected them to be.''

A biologist at the Tuna Research and Conservation Center of the Monterey Bay Aquarium in California, Fudge was one of five scientists aboard Capt. Bob Eakes' surgery boat, The Bullfrog, Thursday who set out across man-sized waves to implant archival tags in tuna.

Anglers from other boats - who pay $800 to $1,000 a day to charter a vessel for six people - voluntarily transfer bluefin they catch to the surgery boats. The captain of the fishing boat throws the surgery boat captain a tennis ball tied to the line that is hooked in the fish. The surgery boat captain pulls the fish through the water, alongside his boat. Then four people lift the beast aboard, put it on a towel, cover its eyes with a wet cloth and stick a hose in its gill to keep water pumping through its body.

Fish Surgeon Tom Williams, also of the Monterey Bay Aquarium, gives the fish a physical. If it is healthy, and at least 6 feet long, he makes an inch-long incision into the bluefin's belly. He inserts the archival tag, puts in two stitches, which will drop out in a couple months, and hooks a green spaghetti-sized tag on each of the fish's shoulders.

Three minutes after it has been brought aboard, the tuna is off the boat, back in the ocean, swimming away.

``It's like a pit stop at the Indy 500,'' Fudge said of the tagging process. ``Move 'em in, hook 'em up, and let 'em go.''

About the size of a fat cigar, with a 4-inch-long plastic, metal-tipped antenna trailing outside the fish, these $1,500 archival tags were designed by Washington state scientist Roger Hill especially for the Hatteras Island tuna study. The battery-operated devices turn on every two minutes to mark the tuna's location, depth, and the water temperature. The tags will collect data for about three years - and store it for up to 22 more.

If anglers catch a tuna with one of these archival tags, they're asked to contact the National Marine Fisheries Service - or radio one of two surgery boats at sea off the Outer Banks all month. The other surgery boat is called The Raptor and, like The Bullfrog, was donated by its captain for the series. The Bullfrog is from Buxton and The Raptor is from Florida.

Federal officials are offering a $1,000 reward for the retrieval of fish with these tags. And Block is offering an additional $1,000. But since the National Marine Fisheries Service closed the angling category of bluefin tuna March 2, only scientists have been allowed to keep the big fish. Fishermen who capture tagged tuna, however, can still receive the reward. They just have to hand over the tuna.

Another type of tag being used is the acoustic tracking tag that was inserted into the 6-year-old tuna off Cape Hatteras two weeks ago. These short-term devices emit a continual signal so boats can follow the fish across the ocean, measuring its speed, distance and diving patterns.

That young tuna swam about eight miles an hour through the Atlantic. ``That's fast for a fish - real fast,'' Block said. ``And that fish obviously survived the tagging.''

Pop-up tags also are being tried in tuna this month. The new technology, which costs $1,800 per tag, was funded by the Packard Foundation and the National Marine Fisheries Service. It lasts up to four months in the fish, then pops up in the ocean and emits a satellite signal showing its location. That way, scientists can tell where the fish swam - and what the water around it was like - without having to recapture the fish.

This week, Block and other surgeons plan to implant 40 satellite tags in giant bluefins off Hatteras. The tags are set to pop up in May through July. Since that's the peak bluefin breeding season in the Gulf of Mexico and the Mediterranean, scientists say they'll be able to tell where the Carolina schools are spawning.

``The most exciting thing about this tagging series so far is knowing that the tags work. The operation is going smoothly and quickly,'' Williams said. ``And the fish are doing fine.''

National Marine Fisheries Service scientists have been tagging tuna with orange tags for more than 40 years. During the last four years, recreational anglers have tagged more bluefin tuna off Hatteras than the total that had been tagged around the world before. Two tuna tagged off the Outer Banks in 1994 and 1995 were recaptured last year in the Adriatic Sea and off the coast of Spain.

``That shows there's some mixing of the Eastern and Western tuna stocks,'' said Dr. Eric Prince of the National Marine Fisheries Service's Miami Tuna Tagging Center. ``And this year, 70 tagged tuna have been recaptured off Hatteras already. About 25 percent of those tuna were tagged off the Outer Banks last winter. That shows the same tuna are coming back to the same spot at the same time of year. Others that have been recaptured were tagged off New England last summer.''

Block said bluefin aren't native to the waters off the Outer Banks.

``Hatteras is just on a flyway,'' she said last week from a rental cottage in Hatteras Village, after spending an exhausting day tagging tuna on the very rough ocean. ``These big bluefin, the 350- to 500-pounders, are just passing by on their way to breed in the Gulf. The medium fish, in the 200- to 300-pound range, seem to be sticking around here for a bit, though.

``The major point we want to solve is the relationship of these Hatteras tuna to all the ther bluefin around the world.

``There's no where else you can do this work - or ever have been able to,'' Block said of the tuna tagging project. ``We've had fantastic cooperation from the local community, and, especially, the anglers. At least 27 boats have transferred fish to us so far. And we've handled 150 tuna for tagging. Fish have ranged from 225 to 575 pounds and from 4 to 10 years old. ILLUSTRATION: Color photo by Drew Wilson/The Virginian-Pilot

Color Map/VP

The Tuna's Track off Cape Hatteras, N.C. KEYWORDS: BLUEFIN TUNA NORTH CAROLINA TAGGING PROJECT

TRACKING PROGRAM

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