The effects of temperature and salinity on egg development and settlement of the ascidian Herdmania momus were investigated. Adult specimens were collected from the Dodu Yacht facility in Jeju Island, Korea (33°30′30.54″N, 126°27′55.46″E) in August 2018. Egg development and larval settlement were observed and recorded at 8 h intervals using a stereomicroscope, under nine temperature (10, 13, 16, 19, 22, 25, 28, 31, and 34°C), and four salinity regimens (28, 30, 32, and 34 psu). The highest hatching rate (82.8±7%) was observed at 32 psu and 25°C and the lowest hatching rate (1.0±2%) was at 34 psu and 13°C. The developmental rate (0.222±0.0994) was highest at 28 psu and 28°C, and lowest (0.016±0.008) at 30 psu and 13°C. The highest settlement success rate (77.1±5%) was at 32 psu and 25°C and the lowest (0.1±1.0%) was at 30 psu, and 13°C. The rate of settlement (0.080±0.000) was highest at 28 psu and 28°C, and lowest (0.013±0.000) at 30 psu and 13°C. Both hatching and settlement success rates increased as temperature increased and tended to decrease beyond an optimal temperature range. Herdmania momus preferred 30-34 psu salinity and 22-25°C temperature. This study provides baseline information about the life history of H. momus, and important data to control the damage caused by the increase in number and distribution of this invasive ascidian.

Abstract
INTRODUCTION
MATERIALS AND METHODS
    1. Collection and rearing of Herdmania momus
    2. Artificial fertilization and egg development
    3. Egg hatching and larval settlement test
    4. Data analysis
RESULTS
    1. Hatching rate of eggs
    2. Egg development to larval stage
    3. Settlement success rate of larvae
    4. Rate of settlement of larvae
DISCUSSION
REFERENCES

• Juun Park(Institute of Marine Life Resources, Sahmyook University)
• Yun-Sik Lee(Institute of Marine Life Resources, Sahmyook University/OJeong Resilience Institute, Korea University)
• Donghyun Kim(Institute of Marine Life Resources, Sahmyook University)
• Sook Shin(Institute of Marine Life Resources, Sahmyook University/Department of Animal Biotechnology and Resources, College of Science and Technology, Sahmyook University) Corresponding author