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Paul Bentzen, professor

A day in the life

Paul Bentzen, professor

Paul Bentzen_Marine Gene Probe_35921 (214x214)

The technology right now is advancing at such an incredible rate, it’s hard to know what we’ll be doing in a few years. We can look at thousands of genes to find out how fish stocks might evolve in response to fishing pressure—it would have been science fiction a decade ago.

Using fish DNA to explore diversity and conservation


Evolution, ecology, and conservation: three pillars of Paul Bentzen’s teaching and research. Dr. Bentzen, professor in Dalhousie’s Marine Biology and Biology Departments, discovered his interests—particularly as they apply to fishes—while doing his PhD in the 1980s. “It was exciting to try the brand new DNA technologies just developing then,” he explains.

Compared to the technologies now in use, technologies of the 1980s were “like candles compared to today’s LED lights,” Dr. Bentzen laughs. “What we can do now was unimaginable before, in terms of DNA sequencing information and the kinds of questions we can ask and answer.”

Questions he’s asking now: “How much dispersal is there between fish populations? What populations should we be managing?”

This also matters in terms of evolution: “We need to understand local adaptations: what are they, and what populations have them? This also relates to conservation and biodiversity at the species level—we know we should protect species, but we also have to think about protecting diversity within species, to anticipate future change.”

Though he’s fascinated with fishes, Dr. Bentzen is rarely on a boat. “I wish I was, sometimes,” he says somewhat wistfully. “But my students gather samples from all over the Atlantic, and sometimes the Pacific and Arctic oceans.”

His students bring those samples back to his Marine Gene Probe lab. This summer, they “collected sticklebacks in coastal areas, to research population genetics on them and their parasites. Parasites go along with the fishes, so they should tell similar stories in terms of population structures,” he explains. “But because they have shorter generation times, they may show a magnified view of evolution.”

For his third-year Molecular Ecology course, Dr. Bentzen sometimes gives students unusual homework: “One year, I had them take DNA samples of seafood from restaurants and supermarkets to see if the labels matched the DNA,” he smiles.

“Don’t ever waste money on red snapper,” he says, explaining that samples from several sushi restaurants turned out to be tilapia. “And sometimes salmon gets labelled ‘wild Pacific’ when it’s farmed Atlantic.”

In Dr. Bentzen’s view, such basic skills in using DNA technology are essential to students considering a future in marine biology or biology. “You need to understand how DNA technology can help answer questions about conservation and management—and it’s really fascinating stuff.”