Estimating target strength and physical characteristics of gas-bearing mesopelagic fish from wideband in situ echoes using a viscous-elastic scattering model.

摘要: Wideband (38 and 50–260 kHz) target strength of organisms were measured in situ using a towed platform mesopelagic (200–1000 m depth) layers. Organisms with gas-inclusion are strong scatterers sound acoustically distinct from lacking one. In the zone, some fish species physonect siphonophores have gas-inclusion. Trawl multinet biological sampling as well photographic evidence indicate that study area (eastern mid-Atlantic Ocean) majority gas-bearing fish. Subsequently, two-layer viscous-elastic spherical gas backscattering model, physical characteristics such gas-bladder features body flesh properties deduced signal individual Acoustic techniques non-extractive, can be used for monitoring quantification marine time- cost-effective manner, suit studies which is logistically challenging. Vessel-mounted acoustics, widely epipelagic studies, has limitations deep inaccessible to high-frequency (≳100 kHz) acoustic pulses transmitted surface due absorption. Therefore, equipped wideband acoustics several utilized dense scattering layers containing mixed species.