"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, described in the Feb. 3 issue of Science, 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."