Changes in Shad and Largemouth Bass Dynamics and Sport Fishery Following a Disease-caused Fish Kill

During spring and summer 1986, a massive disease-caused fish kill occurred on Lake Walter F. George, Georgia, which resulted in significant and longlasting changes in the fish populations of this reservoir. Prior to the fish kill, populations of both threadfin (Dowsoma petenense) and gizzard shad (D. cepedianum) were dominated by intermediate- and harvestable-size fish. Anglers reported largemouth bass (Micropterus salmoides) fishing was poor, and age analysis indicated poor recruitment for several years. Following the fish kill, shad populations were dominated by large numbers of fingerlings, and standing crops of intermediateand harvestable-size shad were much reduced. Large numbers of largemouth bass were recruited to the fishery the year following the fish kill, and recruitment remained good for 8 of the 9 years following the kill. Electrofishing catch of largemouth bass >20 cm total length increased from an average of 26.7 fish/hour for 5 years prior to the fish kill to an average of 63.7 fish/hour from 1987 through 1995. Total harvest of largemouth bass, as estimated by creel surveys, increased 2-4 fold following the kill. Directed catch rates for all sizes of largemouth bass increased from 0.24 fish/hour in 1984 to 0.51 fish/hour in 1987 and remained above 0.40 fish/hour through 1991. By 1989, the 1986, 1987, and 1988 year classes represented 79.9% of the largemouth bass population by number.

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