Effects of temperature on egg production and early life stages of the fountain darter

Studies were conducted to determine the effects of water temperature on egg and larval production, larval survival, and juvenile growth of the endange red fountain darter Etheostoma fonticola. Adult fish were exposed to water temperatures of 14, 17, 20, 23 (control), 25, 27, and 29 degrees C for 33 d . Egg production was significantly higher (P less than or equal to 0.05) fo r fish held at 14, 17, 20, 23, and 25 degrees C than for fish held at 27 an d 29 degrees C. Percent hatch was significantly higher (P less than or equa l to 0.05) at 17, 20, and 23 degrees C than at 14, 25, 27, and 29 degrees C . Larval production was significantly higher (P less than or equal to 0.05) at 14, 17, 20, and 23 degrees C than at 25, 27, and 29 degrees C. Estimate d low and high temperatures to produce 50% mortality of larvae (24-72 h old ) over a 24-h period were 3.8 and 31.9 degrees C, respectively. Low surviva l and substantial variation in growth of controls prevented a meaningful as sessment of temperature effects on juvenile growth.