FORAGING SUCCESS OF LARGEMOUTH BASS AT DIFFERENT LIGHT INTENSITIES - IMPLICATIONS FOR TIME AND DEPTH OF FEEDING

Laboratory feeding trials were conducted to determine how light intens ity affects foraging success by the visual piscivore, the largemouth b ass (Micropterus salmoides). Foraging success was greater than 95% at light levels ranging from low intensity daylight (2.43 x 10(2) lx) to moonlight (3 x 10(-3) lx), but declined significantly to 62% at starli ght (2 x 10(-4) lx) and near 0% in total darkness. Over a range of low to high water clarities (0.5, 2.0, and 4.0 m Secchi depth), estimated depth limits for feeding during the day ranged between 5.5 to 44 m an d from 1.6 to 13 m at night during a full moon. At starlight, light in tensity rapidly attenuated to a level below the feeding threshold with in 0.5 m of the surface at all water clarities. The depth of the water column available for feeding in low clarity water (0.5 m Secchi) was 67 and 75% less than at moderate (2.0 m Secchi) and high (4.0 m Secchi ) water clarities. The findings illustrate how differences in the ligh t environment can have important ramifications for predator-prey inter actions.