GLOUCESTER — Devin Zelck was fast asleep on the deck of the boat Dogbar at 7 a.m. last Friday when the big fish took the bait.

"I woke up to my dad's screaming, 'We're on, we're on!," she said.

Ten hours later, the 18-year-old from Hamilton reeled in a 700-pound giant bluefin, a remarkable catch for an experienced fisherman never mind a teenager landing her first tuna.

Jim Alvarez, the captain of the boat who, along with Zelck's father, helped the teen haul in the massive fish, said it was the biggest tuna he has caught in his 10-year career.

"That's a good way to start off her career," Alvarez said. "She's a tough cookie."

Devin Zelck said she had gone tuna-fishing with her father Steve, a commercial fisherman out of Gloucester, several times but had always came up empty. They headed out at 5 a.m. last Friday on the Dogbar for what was supposed to be a short, half-day trip.

The boat dropped anchor about five miles off-shore when the tuna grabbed one of its lines. Alvarez, who described tuna-fishing as "hours of boredom punctuated by complete insanity," said the next few minutes were "complete pandemonium."

Devin jumped up out of her slumber to pull the other lines out of the water. Steve was on the rod. Alvarez started the boat and got it going in the right direction.

Steve Zelck said the average fight with a giant tuna is 2 1/2 hours. This one lasted 10. "That was obviously a heavyweight bout," he said.

The giant bluefin dragged the Dogbar nine miles, out to Jeffreys Ledge in the Gulf of Maine. Devin and her dad took turns on the line, reeling in the fish and then letting it run in what Steve described as a "tug of war."

"After an hour we realized this fish was not going to give up," Devin said. "It was tiring. I'm only 18. I'm definitely not the strongest. It was definitely challenging for me."

"It takes everything you've got," her father added. "I've still got blisters on my hand."

Finally, when the fish got close enough to the boat, Alvarez threw a harpoon and stuck the bluefin in the middle of its back. Steve Zelck said a fish usually rolls over and dies at that point, but this one took off about 200 feet.

"That tells you how mean it was," he said.

Devin was on the line at the time and cranked the rod to get the fish to the surface. Alvarez and her father got a rope around the tuna's tail and hauled it aboard.

The fish measured 106 inches long and weighed more than 700 pounds, according to the men. They took it to a fish broker in Gloucester and hope to get about $10 per pound.

For Steve Zelck, it was actually his second-biggest tuna. He was 13 years old when he and his high school history teacher landed a 1,000-plus-pound tuna, he said.

"That's what got me into this," he said.

Devin, a Hamilton-Wenham Regional High School graduate who will be a freshman at Endicott College in the fall, said credit should go to her father and Alvarez. But Alvarez made clear it was Devin who deserves the most acclaim.

"She's the star," he said.

Staff writer Paul Leighton can be reached at 978-338-2675 or pleighton@salemnews.com.