Sightings | Alumni Profile

Tagging Giants for Research
Barbara Block Takes on One of the World's Premier Conservation Challenges by Pursuing the 'Most Majestic Fish in the Sea'

by Monte Basgall

At 5 a.m. on cold January mornings, Duke alumna Barbara Block and her fellow giant bluefin tuna taggers are already out on the choppy water off Morehead City, as they have been every year except one since 1996. Under a joint program with North Carolina sport fishermen, called “Tag-A-Giant,” her close-knit teams of students and scientists have been able over this interval to intrude in one of the most exciting rituals in big game angling—all in the interest of research.

By being allowed to surgically implant electronic monitoring instruments into freshly caught specimens of some of the biggest and most commercially valuable fish—then letting the animals loose—Stanford’s Charles & Elizabeth Prothro Professor in Marine Sciences and her fellow investigators have immeasurably advanced what is known about the far ranging, and interestingly warm-blooded, marine species.

Block’s wintertime North Carolina visits—to attach more electronic tags to more giant bluefins—also return her to the Duke Marine Laboratory, where she did field work while earning her 1986 doctorate in zoology from Duke.

In fact, her visits “are absolutely one of the premier events of the winter here,” says Duke Marine Lab Director Michael K. Orbach. “Barb is such an effervescent and well-known scientist, and her surgery teams are such great folks that everyone immensely enjoys having them. We provide her with office space and support for her whole tagging team. Many of our students work with her. I will work with her on everything from relations with local fishermen to periodically helping out on the field team.

"She’s got an incredible amount of energy, and she’s willing to spend it because she feels so strongly that the bluefin tuna situation is probably one of the world’s premier conservation challenges.”

In a 1999 interview at the Beaufort marine lab, Block called the bluefins “the most majestic fish in the sea,” and “the pinnacle of bony fish evolution.” Giant Atlantic bluefins can live 25 years, weigh 1,500 pounds and grow 10 feet long. As a result of tag program data, science now knows that bluefins can dive at least 4,500 feet deep and make immense journeys to and from the Mediterranean coastlines of Sicily and Tunisia and the waters off North Carolina, Massachusetts and Newfoundland. Block’s research also has identified breeding grounds for western Atlantic bluefins in the Mediterranean and the Gulf of Mexico.

“Why are we still going to Beaufort in January?” she asks. “It’s because every year our tracks are getting better. We’re seeing that the animals that might be doing one thing one year are doing something completely different the second and third years. The implantable archival tags have the potential to record tracks of five years. So we can watch an adolescent tuna that we tagged in Carolina make a decision as it matures about where to breed. And the strange aspect of the Carolina fishery has been that we’re seeing as many fish breed in Europe as breed in the Gulf of Mexico.”.

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