Synchronised acoustic and optical measurements of bluefin tuna: from cage monitoring and catch control, in the way to sonar biomass estimates

Abstract

Ventral measurements offer a wide spectrum of automation possibilities of BFT biomass estimations in cages and transfers - A synchronized stereoscopic video+echosounder system allows to asign biometrical data of bluefin tuna to a particular track in an echogram. - Ventral TS (partial TS, operationally defined) correlates with bluefin tuna length. - Partial TS vs Log(L) linear adjustments allow to predict tuna length from "blind" acoustic measurements even with single beam. Ongoing works and needs: -Measurements with broadband (chirped) echosounders and pulse compression technique from different aspects (new multibeam sonar campaings) - Better understanding of bluefin tuna structures contributions through measurements and numerical simulations (better knowledge of BFT anatomy and physiology, 3D biometrics, numerical simulations of TS) - New transfer tests to improve feasibility and technology/methodology cross-checking