"Characterization of sound scattering layers in the Bay of Biscay using broadband acoustics, nets and video" acoustics and biological Data

Sound scattering layers (SSLs) are observed over a broad range of spatio-temporal scales and geographical areas. SSLs represent a large biomass, likely involved in the biological carbon pump and the structure of marine trophic webs. Yet, the taxonomic composition remains largely unknown for many SSLs. To investigate the challenges of SSL sampling, we performed a survey in a small study area in the Northern Bay of Biscay (France) by combining broadband and narrowband acoustics, net sampling, imagery and video recordings. In order to identify organisms contributing to the observed SSLs, we compared measured frequency spectra to forward predicted spectra derived from biological data. This dataset comprises the echo-integrated broadband acoustic data (in Sv(f)), the nets position and depth, and the abundance and the size of the catched organisms acquired during a specific operation of SSLs sampling during PELGAS 2016. The acoustic data have been echo-integrated by cells of 5 ping in horizontal and 1.5 meter in vertical. The biological data comes from video counting, direct measurement, ZooCAM or ZooScan plankton imagerie tools; they were generally identify at a low taxonomic level, but sufficient for the modelisation of their acoustics backscattering. More detail of the biological/acoustical data acquisition and processing can be find in Blanluet et al., (under review). This dataset was used in Blanluet et al..