Estimation of potential annual fecundity, as measured by a determinate fecundity method, relative to fish size (log-log transformation).

The size-specific estimate decreases once a fish shows evidence of spawning (see text). The four sampling events and associated correlation coefficients are: A) pre-spawning fish in the lower river (April 30–May 6, r = 0.36, n = 25, P = 0.08), B) pre-spawning fish collected at Hadley Falls Power Station (May 12, r = 0.65, n = 20, P = 0.002), C) spawning fish collected at Hadley Falls and Cabot Power Stations (May 12–13, r = 0.63, n = 11, P = 0.04), and D) spawning fish collected at Hadley Falls and Vernon Power Stations (May 19–20, r = 0.41, n = 10, P = 0.2). Individual fish are plotted as dots, the predictive regression is a blue line, and the 95% confidence limits are enclosed in solid gray.