Fisheries ecologist Lisa Kerr has been at the Portland-based Gulf of Maine Research Institute for four years, researching fisheries with the aim of improving sustainability management and understanding the ecosystem as a whole, as well as how it might be changing. She is the expert on all things cod and bluefin tuna. We called her up to talk science and in the process learned about her mother’s cool summertime rule, how the Bahamas played a role in her career and what the inner ear bone reveals about fish.
WHEN DID YOU KNOW? Kerr grew up in Hingham, Massachusetts, and did her undergraduate work at Tufts, where in her sophomore year, “I really caught the science bug and decided if I could figure out a way to do this I would.” Small wonder: She got to go on a tropical field ecology course on a private island in the Bahamas with a field station. It was only two weeks, but “I just loved it.” That, she concedes, was one of the more glamorous scientific trips she took, but when she went back to Tufts, she got involved in working in marine labs. “A lot of microscope work.” She also co-authored her first paper with one of her professors, on the bioenergetics of marine worms. That would be? Basically, “how much they eat and excrete.” She got hooked on the publishing side of science.
SHARK TANK: After Tufts, Kerr went back to the Bahamas, where she spent six months at a shark research lab. “Tagging and tracking lemon sharks, doing shark dives and things like that.” Kerr was ready then to go to graduate school at Cal State’s Moss Landing Marine Laboratories. She lived in Monterey, California, “a great place to do marine science. Those kind of epic kelp forests and sea life.” After getting her master’s, she crossed the country again to get her Ph.D. at the University of Maryland, working at the Chesapeake Biological Laboratory. Her specialty was understanding population structure in fish groups. She focused on white perch, which in that region spawn in fresh water and then move into higher salinity waters.
HOME SWEET HOME: From there, Kerr did a post-doctoral program at the University of Massachusetts Dartmouth. “I really wanted to get back to New England,” she says. “This is the ocean environment I grew up with, and I feel most invested in making a difference here.” Was there lots of beach time growing up on the South Shore in Hingham? Yes, but there were also summers in Cape Cod, with a mother who’d tell Kerr and her two brothers, after they made the trek to the Cape, ” ‘We don’t cross the bridge again until you guys have to go back to school.’ She was adamant.” There were tide pools and days on the beach, and “you just wore your bathing suit the whole time.”
WARM WATERS: The move to Maine to work at the Gulf of Maine Research Institute was welcome, although the actual Maine water? “It is still a little hard for me to get in. I still go down to the Cape sometimes to get my fix of swimming.”
BLACK BOX: At GMRI, Kerr uses tools she developed during her post-doctoral work, including looking at the otolith – the inner ear bone of a fish – for clues. “It’s essentially like a black-box recorder for the fish,” Kerr explains. “It records all this information. When you count the rings, it’s like tree rings, you can count the age of this fish.” It’s also possible to learn where the fish came from. “If you were born in a certain estuary, you kind of have this fingerprint in the bone about where that was.” With the bluefin tuna, a species she works with frequently, a fish spawned in the Gulf of Mexico is likely to return there to spawn, even if has wandered all the way across the Atlantic. “It’s pretty phenomenal.” The origin of the fish comes into play when the fishery is being managed. “The way we manage bluefin is they have drawn a line down the middle of the Atlantic. But the fish, of course, ignore this line, and we know that bluefin migrate all over the place. Some of my work is around, how do we manage the fish if they are ignoring our line?” For instance, the bluefish tuna population from the Mediterranean is more abundant than the Gulf of Mexico population. “We are making sure that we don’t unintentionally over-exploit the Gulf of Mexico population.”
CLOSER TO COD: She also works a lot with cod in the Gulf of Maine, or rather, with the different groups of cod, i.e., the winter spawning and the spring spawning and then the Eastern Georges Bank species. There’s far more diversity than scientists used to know about. “Not all cod are created equal.” Those three groups spawn at different times, for instance. “Cods are hedging their bets. You don’t want to put all of your eggs in one basket, so to speak. We compare it sometimes to an investment portfolio,” Kerr says. “Some of my research is on understanding where fish move and how these populations mix with each other.” And calculating to see which one, if any, can bring back the fishery. While much of her work involves mathematical modeling and computers, she does relish a chance to get out in the field whenever possible. For the last couple of years, that’s meant going out on a cod project with a commercial fisherman. “A big part of what we do at GMRI is really trying to engage with fishing partners. The fishermen have been in these waters for 30 years. They know where these fish are.”
ON THE PLATE: She’d like to see the groundfish population rebound. “A couple of the flounder stocks are not doing so well,” for instance. With all that she knows, does Kerr feel OK about eating fish? “I enjoy seafood, I eat seafood, I hope other people enjoy seafood. Something people really don’t know is that the U.S. has some of the best-managed fisheries in the world. That doesn’t always get as much press as I think it deserves.” As you wish.
Mary Pols can be contacted at 791-6456 or at: