On the Tail of a Tuna
Tracking bluefin with the Marine Science Research Station
The premiere of Wicked Tuna, a National Geographic reality fishing series filmed out of Gloucester, has prompted new discussion and controversy over whether the practice of fishing bluefin tuna is sustainable.
Views differ among conservation groups, scientists, and fishermen about how many bluefin there are in the world, so that is where the UMass Amherst Marine Science Research Station, directed by marine biologist Molly Lutcavage, steps in.
Lutcavage’s lab, the Large Pelagics Research Center (LPRC) housed at the Marine Station in Gloucester, has developed an innovative, humane way to help track the movements and distribution of bluefin tuna.
Lutcavage and colleagues track bluefin with satellite tags to give the most accurate view of their migration patterns and behavior. The LPRC also uses sonar and aerial surveys to count the fish without ever having to catch them.
Population counts in traditional tuna “tour dates” might be down, even though eyewitness reports by fishermen suggest otherwise. The reason for the discrepancy, says Lutcavage, is that most estimates of fish populations are based on “catch statistics”: how many of a species show up in a fishing net. “Basically,” she quips, “if you don’t catch it, it doesn’t exist.” If fish shift their migration patterns so that fewer of them are in an accustomed location, their population level can appear to be down. Therefore, catch statistics alone make an unreliable source for a highly migratory fish like bluefin tuna.
Lutcavage’s team of researchers tags bluefin with small electronic data loggers when the fish are “tiny” (adults can grow to 1200 pounds) to track their wide-ranging migration patterns from growth to maturity. These tags remain on the fish for up to a year recording depth and temperature. Then they pop off to transmit the data and the location of the fish through satellites to the research station.
LPRC scientists are learning where bluefin tuna spawn, and their peregrinations to different parts of the Atlantic Ocean through their life cycle.
Both the fishing industry and conservation advocates value sustainability. Lutcavage hopes her data will help support beneficial policy decisions, and she asserts that science doesn’t take sides: “Our aim is to be honest brokers of scientific information.”