드론을 이용한 새만금 방조제 외해역에서 상괭이의 단기간 출현양상 및 공간분포 변화 연구 = Short-term Changes in Appearance and Distribution Patterns of Finless Porpoises (Neophocaena Asiaeorientalis) Outside the Saemangeum Dike using Unmanned Aerial Vehicles

다국어 초록 (Multilingual Abstract)

Spatial distribution of finless porpoises (Neophocaena asiaeorientalis) was investigated with respect to the operation of water sluices. A total of 28 times of hourly observations using drones, covering 4 km2 in each flight outside of the Saemangeum dike, were performed for 4-6 hours per day in consecutive two days in March, April, and May 2022, respectively. During the entire study period, porpoises were observed in a total of 1570 times, covering 77% of survey area with appearance of the porpoise at least one time. Porpoises were most frequently observed and widely distributed in April, e.g., 7 times/4km2 in March, 81 times/4km2 in April, and 71 times/4km2 in May, and Spatial extent was reached to 5% in March, 25% in April, and 19% in May. Number of appearance and spatial extent of porpoises were significantly greater when the gate was open than those when the gate was closed. Temporal appearance of porpoises reached highest in one hour before the gate was open, and then decreased. The porpoises gathered in area of 1 km2 near the water gate when the gate began to be open. This study reported the first case that finless porpoises happened to change their behavior in terms of the gate operation of Saemangeum dike, and further causality studies are necessary to link gate operations to porpoise behaviors.