Sensors aid fish census

Researchers at MIT have found a new way of looking beneath the ocean surface that could help definitively determine whether fish populations are shrinking.

A remote sensor system developed by Associate Professor Nicholas Makris of mechanical engineering, along with others at MIT, Northeastern University and the Naval Research Laboratory, allows scientists to track enormous fish populations, or shoals, as well as small schools, over a 10,000-square-kilometre area, an improvement over conventional technology that can survey only about 100 square metres at a time.

"We're able to see for the first time what a large group of fish looks like," said Makris, who compared the dramatic improvement to the difference between seeing everything on a television screen and seeing only one pixel.

The new sensor system could allow government agencies to figure out what's really happening to fish populations, which many environmentalists and scientists believe are in rapid decline.

"The world's fish stocks are being depleted at a horrible rate," said Makris, who attributed declining populations to overfishing, a problem that has been abetted by inaccurate fish counts. "One of the reasons (for the inaccurate counts) is the darkness in the ocean. You don't know what's going on."