Age, Growth, Reproduction and Population Structure of the Striped Shiner (Luxilus Chrysocephalus) and Duskystripe Shiner (Luxilus Pilsbryi) in the James River, Missouri

The purpose of this study was to estimate age for the striped shiner (Luxilus chrysocephalus) and the duskystripe shiner (Luxilus pilsbryi) using asterisci otoliths, scales, and length-frequency data. Monthly samples of both species were obtained from the headwater reaches of the James River in southwest Missouri from February 1998 to January 1999. Total samples were 242 L. chrysocephalus and 322 L. pilsbryi. Otolith ages were validated using marginal increment analysis. A single opaque region was formed in otoliths during the month of May in L. chrysocephalus and the months of June and July in L. pilsbryi. The agreement between otolith age and scale age was 96% for L. chrysocephalus and 82% for L. pilsbryi. Estimated ages ranged from 0 to 6 years for both species. Males of both species were found to have faster growth rates and larger maximum sizes than females, but in both species the oldest individuals were females. Gonadosomatic Index (GSI) data suggested that both species spawn during May and June. Otoliths are a more reliable estimator of yearly age than scales for both species, suggesting that ages may be underestimated for shiners in other studies