Excellent Swimmer, Great Personality

Charismatic characters: two of the clownfish Peter Buston and his students are studying in the CAS prof’s laboratory. Photos by Kalman Zabarsky

Fish may be smarter than you think. When stuck on an angler’s line, striped bass have been known to wrap the line around a rock to shear it when the fisherman reels it in. Octopi and squid have been taught to open jars. Now a BU biologist says our piscine friends don’t just have brains; they have personality.

After observing clownfish, those endearing protagonists of Finding Nemo, Peter Buston, a College of Arts & Sciences assistant professor, has concluded that Disney was right about the orange and white fish not being funny—but they are positively charismatic.

“There will be some very aggressive individuals,” he says, “and some much more social individuals” that are not aggressive. Buston and his students also observed adventuresome fish, who will swim further from their sea anemones (the tentacled host animal in which clownfish live for protection from predators) for longer periods. One barometer of personality is that behavior is consistent over time, and these animals are nothing if not consistent. “The individuals who didn’t travel very far on one day were the individuals who also didn’t travel very far the next day,” he says. “Individuals that are really active are consistently very active.”

Buston isn’t taking Nemo’s word for these personality quirks. He and his students, working through the Undergraduate Research Opportunities Program, which offers BU undergrads the opportunity to participate in research projects with a faculty mentor, trained video cameras on seven pairs of (not romantically involved) clownfish in 30-gallon tanks at the biology department. (Clownfish don’t wander far from their anemones in the wild, so the constraints of a tank, even a big one, don’t impede accurate observation.) They taped them for 10-minute intervals twice a day for three days. The cameras captured whether the fish left their anemone and how far they traveled, the time spent outside of the anemone, and how they acted with each other.

“This is uncharted territory,” says Curran Uppaluri (CAS’13), one of Buston’s student assistants, who says he joined the project because it enabled him to follow a hypothesis through to a “full-fledged experiment with telling results.

“Also,” he says, “it didn’t hurt that the clownfish were excessively adorable.”

Research conducted elsewhere has found distinctive traits among many marine animals—for example, eels and groupers are cooperative souls, known to help one another hunt prey. For Buston, the bigger question is why a variety of personalities in a single species is maintained by natural selection. After all, if evolution suggests that certain traits are better suited to adapt an individual to his or her environment and will be passed on, what can be good about varying traits?

His next research will try “to understand if different personalities do better in different contexts.” For instance, boldness in venturing far is helpful if a fish needs to find new food supplies, but when a predator is prowling around your anemone, discretion could be the better part of valor.

These further studies will require lots of fish, about 180, and lots of time—“30 or more years,” Buston says. “So assuming that I were to get tenure, then I would be working with them until I retire.”