Target strengths of two abundant mesopelagic fish species

• DOI: 10.1121/1.4906177
• Publication Date: 2015-02-18T18:00:37Z
• Authors: Ben Scoulding; Dezhang Chu; Egil Ona; Paul. G. Fernandes
• Keywords: Mesopelagic zone; Target strength

Mesopelagic fish of the Myctophidae and Sternoptychidae families dominate biomass oceanic deep scattering layers and, therefore, have important ecological roles within these ecosystems. Interest in commercial exploitation is growing, so development techniques for estimating their abundance, distribution ultimately, sustainable are essential. The acoustic backscattering characteristics two size classes Maurolicus muelleri Benthosema glaciale reported here based on swimbladder morphology derived from digitized soft x-ray images, empirical (in situ) measurements target strength (TS) an survey a Norwegian Sea. A model gas-filled prolate spheroid was used to predict theoretical TS both species across frequency range between 0 250 kHz. Sensitivity analyses modeling parameters indicate that rather sensitive viscosity, volume ratio, tilt, which can result substantial changes TS. Theoretical predictions close resonance were good agreement (±2 dB) with mean situ areas acoustically surveyed spatially temporally consistent trawl information species.