| Abstrakt: |
The times and patterns of feeding of 1,366 bluegill in two heated reservoirs of Texas were studied by the “points” method for over a year. Fish were collected on alternate hours from an electric power plant discharge canal and an open-water station in each reservoir over 24-hour periods. Both average index of fullness of the stomachs and average points per fish showed a similar diel pattern of feeding. The fish were largely diurnal feeders with a nocturnal component. The stomachs contained least food during the period from 0200 h to 0800 h. Feeding increased after sunrise, and the fish showed a minor peak by 0900-1000 h and a major peak by 1800-1900 h. A gradual decline in food volume began after 1900 h and continued until 2200 h, followed by a sharp decline at 2300 h. A diverse range of food organisms was consumed by the fish during the daylight hours. Planktonic crustaceans and nonaquatic organisms were rarely found in the stomachs of the fish taken at night. In the discharge-canal fish, 75% fullness of the stomachs occurred by 0900 h, but in fish from the open waters, comparable stomach fullness did not occur until 1400-1600 h. |
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