Some Effects Of Supplemental Feeding And Controlled Fishing In Largemouth Bass-Bluegill Populations

The effects of supplemental feeding and controlled fishing in sUPPlementally fed largemouth bass-bluegill populations were studied in one control pond and two treatment ponds. The ponds were stocked in March and April, 1963. One treatment and the control pond were drained in October, 1964. The objective of this phase of the study was to determine the effects of supplemental feeding on growth rate, condition index, and survival of bluegill, and on population balance and total production. A second phase of the experiment, restricting the harvest in a given time interval on a 3.5-acre pond, was begun in 1964 and terminated in October, 1967. Bluegill in all ponds grew at comparable rates for the first 6 months after stocking. Seven months after stocking, bluegill in the treatment ponds were significantly heavier than those in the control pond. However, length-weight computations indicated that differences in condition indices between treatment and control ponds began to develop in the fifth month when the bluegill were in the 4-inch group. The two treatment pond populations were still expanding when the first phase of this study was terminated after 19 months of culture, but the control pond population had become. static (Le., no reproduction) by that time. When the control pond and treatment pond were drained in 1964, no significant difference between survivals of originally stocked bluegill in these ponds was found. The difference between total bluegill productions in those two ponds was 308 pounds per acre after 19 months. The difference between standing crops in the control pond at draining in 1964 and in the treatment pond drained in 1967 was 768 pounds. This difference was considered to be approximately equal to difference in carrying capacity between these two ponds since both populations were static when the ponds were drained. Total production per acre in the fished treatment pond for the 4-year period was 2307 pounds including 2194 pounds of forage fish. The pond had a standing crop of 1129 pounds when drained. Conversion (S) of the 8766 pounds of feed used to produce the 2194 pounds of forage fish was 4.0 at a cost of $0.22 per pound. Fishing success for the 4-year period averaged approximately 60 percent better than in 20 Alabama state-owned fertilized lakes over a 14-year period.

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