Preliminary study of passive acoustic monitoring of finless porpoises Neophocaena asiaeorientalis around the Southwest offshore wind farm in Korea

Due to the accelerated development and transformation of coastal waters by humans, damage to marine mammals is a concern. To understand how coastal development may affect marine mammals, it is essential to determine their distribution characteristics. In this study, the appearance of finless porpoises was confirmed by passive acoustic monitoring around the Southwest offshore wind farm in July, 2020. Although there were no visual observation results of finless porpoises in the research area, the clicks measured in the offshore wind farm were verified by comparing with acoustic characteristics of the clicks measured in the area with a high detection rate. During the experimental period, clicks of finless porpoises were recorded for ten consecutive days, and Clicks per Porpoise Positive Minute (CPPM) was 40.7 clicks min-1, Porpoise Positive Minutes (PPM) was 9.7 %, Encounter duration and waiting time were 18.2 min and 94.9 min respectively. This study provides information on the appearance of them in the Southwest offshore wind farm and this result may help to monitor the impact of marine mammals from wind farm operation.