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Control and exposed fish are simultaneously videotaped in multiple test arenas. The analog video (see sample movie below) is then digitized and processed prior tracking the individual fish. Tracked fish are evaluated by determining changes in their x,y coordinate positions through time (see sample fish path below movie), and a variety of questions can be asked about their movement relative to exposure to certain stressors.

This movie is a processed digitized video clip of 5 mummichogs (Fundulus heteroclitus) swimming in an experimental vessel. Once the video has been digitized, edited, and tracked using commercially available software, the data is then transformed into relevant variables by computer software developed at the Aquatic Pathobiology Center. Variables calculated by the software include: total distance traveled, velocity, angular change, fractal dimension, NND (nearest neighbor distance), NNA (nearest neighbor angle), school area, polarity (direction of travel of each individual in relation to the entire school), and interactions between individuals.