Population Characteristics of White Bass and an Evaluation of Minimum Length Limits in Kentucky Lake, Tennessee

Relatively few studies have been conducted for white bass (Morone chrysops) populations in large river impoundments. Our study focused on population characteristics of white bass in Kentucky Lake, a mainstem impoundment of the Tennessee River. A total of 994 fish were collected using electrofishing during April 2006 and 2007 to evaluate age, growth, and mortality. Kentucky Lake white bass exhibited relatively fast growth compared to previously studied populations. Females were already larger than males by age-1 and continued to grow faster than males; both genders were sexually mature by age-2 when complete recruitment to the fishery occurred. Mortality did not differ between males and females and the pooled annual mortality rate (A) was 45%-46% each year. Beverton-Holt equilibrium yield models were used to evaluate the potential for minimum-length limits (MLL; 254 mm [no MLL], 279 mm, 305 mm, and 305 mm) to increase yield and harvest potential in the population. Yield models were run at two conditional natural mortalities (0.35 and 0.45) and varying exploitation. These models did not predict appreciable changes in yield or number of fish available for harvest across MLLs. Although Kentucky Lake white bass grew rapidly, a MLL for white bass was not recommended because the models predicted only nominal benefits. Future evaluations of size limit feasibility should include a concurrent exploitation study to better determine the relative influence of natural and fishing mortalities in the yield models.

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