BASS POPULATION AND RATE OF CATCH 



At Ridge Lake, experiments in largemouth bass management have been in progress 

 since 1941. This 18-acre artificial impoundment, which is about 7 miles south of Charleston, 

 is opened to the public for fishing under a permit system developed to allow a complete in- 

 ventory of all fish caught. In the early spring of every other year the lake is drained, and 

 the fish are taken from the lake, counted, and weighed. Some water is then allowed to col- 

 lect behind the dam, and fish (bass and sometimes other species) large enough to be caught 

 by anglers are marked and returned to the lake. The lake basin usually is full again by the 

 opening of the bass season in June. 



In 1949, the Icike was drained in March and a population of bass and bluegills was 

 removed and censused. Following the census, 1,027 marked bass were returned to the lake, 

 but the bluegils were not. Rainfall was subnormal during the spring months of 1949, and by 

 June 1 the water level of the lake was up only to the ll-acre contour. Thus, all of the larger 

 bass that had developed in 18 acres of water were concentrated in an ll-acre lake; the popu- 

 lation density per acre was about 93 bass weighing 73 pounds. Also, one of the important 

 sources of bass food, the bluegill population, had been eliminated. Conditions seemed op- 

 timum for excellent bass fishing. 



In test fishing operations from June 1 to June 14, Natural History Suryey personnel 

 caught 50 bass weighing 52.5 pounds in 1 7 hours, 45 minutes. This catch gave a calculated 

 average rate of one bass per 24 minutes of fishing or 1 pound of bass per 18 minutes. The 

 lake was opened to public fishing on June 15. Once a concentration of fishermen appeared on 

 the lake, the bass quickly became wary, and the catch rate dropped from a high rate early in 

 the first day of public fishing to a much lower rate before the end of the day. The rate for 

 the day was only one bass per 2.3 hours. The catch rates for the second to fifth days, in- 

 clusive, were one bass per 5.6, 14.3, 10.0, and 11.1 hours, respectively. Fishing improved 

 somewhat during July, but never was better than an average of one fish per 5 hours for any 

 week. 



The reduced rate of catch which began at Ridge Lake before the end of the first 

 day of the open season, after less than 10 man-hours of fishing per acre, is believed to rep- 

 resent a normal response of bass to intensive fishing. A marked drop in catch rate has 

 occurred before the end of the first day of fishing in every year of fishing at Ridge Lcike and 



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