Temperature and pH-Related Mortality of Red Drum Larvae in Fertilized Culture Ponds

Abstract Survival of larval red drum Sciaenops ocellatus (36 h posthatch) stocked into fertilized culture ponds was monitored to determine the effects of temperature and pH. In 108 pond trials, larvae were stocked at pH values ranging from 8.5 to 10.8 and temperatures ranging from 19.8°C to 30.8°C. Fish were acclimated for 15–25 min before stocking. Culture ponds were stocked only when temperature, dissolved oxygen, and salinity were conducive to survival. In addition to pH and temperature, ponds were monitored for dissolved oxygen and salinity over a 3-d period before sampling. Pond stocking success was based on the results of ichthyoplankton tows where less than 50 larvae/tow was considered failure and 50 or more larvae/tow was considered success. Ponds with a maximum pH of 9.4 and above had reduced survival (<50% stocking success). Survival increased with increasing water temperature. Elevated pH levels and low water temperatures in fertilized culture ponds can reduce survival of red drum larvae. Stock...