Abstract
The common snook, Cenfropomus undecimalis, is a largely tropical species ranging from North Carolina to Brazil (Rivas, 1986). It is a highly-prized gamefish in Florida, where considerable effort has been expended toward culture. In this study, daily swimming activity of juvenile snook was examined in the laboratory using photoelectric techniques. Patterns of locomotion are described with respect to periodicity phase and ecological implications. Swimming velocities are estimated in an attempt to quantify routine activity.