Relationship between hatch date and first-summer growth of five species of prairie-stream cyprinids

Stream fishes often exhibit a bet-hedging multiple spawning reproductive strategy. In many species, the reproductive season lasts several months. This exposes young fishes to varying environmental conditions that may differentially affect growth. We studied the effect of hatch date on first-summer growth among members of a prairie-stream fish assemblage. The reproductive season in both years of the study was protracted, lasting from April through August. Due to intermittent stream-discharge, there were two distinct periods during which most species successfully reproduced. In general, growth rate was greater among individuals with an early hatch date than among those with a later hatch date. Multiple regression models indicated that hatch date was related to growth in all study species with one exception (red shiner, Cyprinella lutrensis). The results of this study provide evidence that young-of-the-year of multiple spawning stream-fish species that are spawned late in the season may grow at a slower rate than young spawned earlier in the season.