Detections of biological sounds and mapping of acoustic presence of marine organisms

Abstract

Many species of marine organisms have been known to produce sounds, which represents species or family characteristics. Passive acoustic monitoring is widely applied for the monitoring of presence and distribution of marine mammals since the species-specific sound characteristics are well identified. In the present study, sounds of damselfish, silver croaker as well as biosonar sounds of high frequency cetacean and impulse sounds potentially produced by snapping shrimp were extracted from towed and fixed passive acoustic monitoring systems off Japanese waters. Results show the scattered spots of damsel fish in a coral reef and dense aggregation of silver croakers in specific area. Acoustic distribution of silver croakers and finless porpoises was similar each other that suggested co-existence of prey and predator in highly productive area due to river discharge. Pulse sounds distribution was different from others. Towed passive acoustic monitoring provided snap shot acoustic distributions of multiple species. Day-by-day change of acoustic distribution recorded by fixed passive acoustic monitoring systems could be used for the adaptive management of marine organisms.