Foraging success of largemouth bass at different light intensities: implications for time and depth of feeding |
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Authors: | T E McMahon S H Holanov † |
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Institution: | Arizona Cooperative Fishery Research Unit, School of Renewable Natural Resources, University of Arizona, Tucson, Arizona 85721, U.S.A. |
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Abstract: | Laboratory feeding trials were conducted to determine how light intensity affects foraging success by the visual piscivore, the largemouth bass ( Micropterus salmoides ). Foraging success was greater than 95% at light levels ranging from low intensity daylight (2.43 × 102 lx) to moonlight (3 × 10−3 lx), but declined significantly to 62% at starlight (2 × 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 and from 1.6 to 13 m at night during a full moon. At starlight, light intensity rapidly attenuated to a level below the feeding threshold within 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 light environment can have important ramifications for predator-prey interactions. |
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Keywords: | Micropterus largemouth bass foraging light intensity |
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