Influence of fish backbone model geometrical features on the numerical target strength of swimbladdered fish

[EN] The method of fundamental solutions has been applied to evaluate the influence of fish models geometrical features on the target strength (TS) directivity and TS frequency response of swimbladdered fish. Simplified models were considered for two fish species: gilt-head sea bream (Sparus aurata, Linnaeus 1758) and Atlantic salmon (Salmo salar, Linnaeus 1758), and different geometrical details of their morphology were studied, such as backbone presence, and its curvature or the inclusion of vertebrae modulation. Swimbladder shape and tilt, together with the inclusion of backbone (and its realistic curvature) for dorsal measurements were the most important features for proper estimation of mean TS. The estimation of mean TS is considered including the effect of fish tilt, the echosounder frequency, and the fish-to-transducer distance.
This work received funding from ACUSTUNA project ref. CTM2015-70446-R (MINECO/ERDF, EU). LG acknowledges the support by FCT-Fundacao para a Ciencia e a Tecnologia, I.P., within the scope of the research unit "Institute for sustainability and innovation in structural engineering-ISISE" (UIDP/04029/2020) and of Regional Operational Programme CENTRO2020, within the scope of the project CENTRO-01-0145-FEDER000006 (SUSpENsE). IP-A and VE acknowledge the financial support of Generalitat Valenciana by grants BEST/2018/119 and BEST/2019/008.