A Comparison of Gill Netting and Electrofishing as Sampling Techniques for White Bass in Missouri's Large Reservoirs

Abstract

I compared fall gill netting with spring electrofishing to determine which method best represented the population abundance and size structure of white bass Morone chrysops in two Missouri reservoirs. Gill nets caught all ages and sizes of white bass, and both sexes were equally represented. Median catch rates were variable but were usually less than 10 fish/gill-net day. Mean annual electrofishing catch rates peaked after mid-April and ranged from about 50–180 fish/h. Electrofishing did not reflect the size structure because it caught primarily male white bass (about 90% of the sample), which are smaller than females of the same age, and the catch rates of immature (age-1) fish were low (usually < 10 fish/h). The catch rates of the two methods were not related to each other, but both appeared to reflect large changes in population abundance. The age frequencies of the sexes and the relative differences in year-class strength were similar with both methods. I recommend fall gill netting for sampling white bass in Missouri reservoirs because all ages and both sexes were represented in the samples, which resulted in earlier assessments of recruitment and better assessments of size structure.