This thesis evaluated responses by migratory spawning phase sea lampreys to trap lighting in the laboratory and field with the aim of improving trapping as' a method of sea lamprey control. It was hypothesized that lit traps would catch more sea lampreys than unlit traps because light would improve: attraction to, entrance into and retention in traps. Trap lighting improved trapping success in the laboratory by attracting sea lampreys to trap entrances. Light was not found to improve attraction to, entrance into, or retention inside traps in the field. This difference in behaviour possibly occurred because light cannot attract sea lampreys over large distances (more than a few feet). Overall, I conclude that the implications of trap lighting for sea lamprey control are limited and weak.