Influence of Stream Flows and Stock Size on Recruitment of Arctic Grayling (Thymallus arcticus) in the Chena River, Alaska

Abstract

The hypothesis that recruitment of Arctic grayling (Thymallus arcticus) in the Chena River is influenced by stream flows and stock size was tested using population data collected from 1976 through 1990. Recruitment may be influenced by stream flows during the initial weeks of life of Arctic grayling, namely during spawning, emergence, and the larval stage. Using correlation and regression analyses, stream flow during the time-frame was found to be a significant descriptor of variability in recruitment (r = −0.751, P = 0.005). Although stream flows were implicated in recruitment variation, creation of an environment-dependent, stock–recruitment model was not possible because estimates of measurement error were lacking, because of bias due to the relation between residuals and subsequent stock size, and because of the presumed autocorrelation of stock size. An alternative analysis was conducted to investigate the influence of stock size on recruitment when stream flows were thought to minimally affect recru...