SynopsisThe effect of constant incubation temperatures (between lo" C and 26" C) on the developmental rates was found to fit a similar exponential relationship in both the lake and white sturgeon embryos and larvae. Although the lake sturgeon had an overall slower rate of development than the white sturgeon, no statistically significant difference was detected in the slopes of the exponential equations describing the effect of temperature on developmental rate. The effect of these incub'ation temperatures on embryonic survival also did not differ between these two species. Both species exhibited optimal survival between 14-17" C and incipient mortalities occurred at 20" C. Temperatures above 20" C were lethal for white sturgeon embryos. No effect of low incubation temperature on survival was evident from this study. A comparison of these North American species with Eurasian acipenserids suggests that all the Isturgeon that have been examined exhibit a similar influence of incubation temperature on developmental rate.