Comparison of stationary acoustic monitoring and visual observation of finless porpoises

• DOI: 10.1121/1.3021302
• Publication Date: 2009-01-21T23:26:14Z
• Authors: Satoko Kimura; Tomonari Akamatsu; Kexiong Wang; Ding Wang; Songhai Li; Shouyue Dong; Nobuaki Arai
• Keywords: Animal Communication; 0103 physical sciences; Visual Perception; Animals; Observation; Acoustics; Porpoises; 14. Life underwater; 01 natural sciences

The detection performance regarding stationary acoustic monitoring of Yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis was compared to visual observations. Three stereo data loggers (A-tag) were placed at different locations near the confluence Poyang Lake and River, China. presence number determined acoustically visually during each 1-min time bin. On average, detected 81.7±9.7% entire effective observation time, while animals confirmed 12.7±11.0% time. Acoustic indicated areas high low porpoise densities that consistent with direction movement monitored using beams, which agreed observations all locations. methods could determine group sizes up five ten individuals, respectively. While method had advantage probability, it tended underestimate size due limited resolution sound source bearing angles. proved be a practical useful alternative observations, especially in density for long-term monitoring.