Variation in Gonad Development, Growth, and Condition of White Bass in Fall River Reservoir, Kansas

Abstract

White bass Morone chrysops were sampled monthly from March 1996 to August 1997 in Fall River Reservoir, Kansas, to document the temporal variation in gonad development, growth, and condition. Both females and males reached sexual maturity at age 2. Mean egg diameter varied temporally, with the largest egg diameters occurring from March through May. Age structure was skewed toward younger ages, with 91% of the females and 94% of the males sampled being less than age 5. Growth in length and weight varied between sexes; females grew faster in both length and weight than males. Mean length and weight varied temporally by sex and year-class. The highest specific growth in length and weight occurred during the summer and fall. During late winter and spring, fish lost up to 7% of the growth in weight from the previous year. The variation in the gonadosomatic index (GSI) for females paralleled that in egg diameter, with the highest GSI values occurring in spring. The decline in weight during late winter and spring, coupled with the increase in GSI, indicated that somatic growth decreased during the spring. Relative weight was variable among seasons and was correlated with length only during the summer. The variation in growth and condition were best explained by the abundance of age-0 gizzard shad Dorosoma cepedianum. These data characterize the highly dynamic nature of gonad development, growth, and condition of white bass in a Kansas reservoir.