2025_programme: Characterisation of aggregated Baltic herring – technique for assessment of possible vessel avoidance reaction
- Day: June 16, Monday
Location / Time: C. THALIA at 18:20-18:40
- Last minutes changes: -
- Session: 10. New frontiers in fisheries acoustics: applications, analysis, decision and management tools
Organiser(s): Victor Espinosa
Chairperson(s): Victor Espinosa
- Lecture: Characterisation of aggregated Baltic herring – technique for assessment of possible vessel avoidance reaction
Paper ID: 2303
Author(s): Aleksander Żytko, Natalia Gorska, Dezhang Chu, Beata Schmidt
Presenter: Natalia Gorska
Abstract: The orientation of herring individuals significantly influences their backscattering properties, which are crucial for accurate hydroacoustic biomass assessments. Vessel-induced avoidance reactions may alter fish orientation distributions during biomass measurements, as observed in many species. However, according to our best knowledge, there is a gap in information regarding the orientation of aggregated Baltic herring as well as its reaction on the approaching vessel during the biomass estimation campaigns. \nTo address this gap, we developed an inverse method for assessing the orientation of aggregated Baltic herring. The method compares histograms of herring target strength (TS) obtained numerically for the different fish orientation distributions with TS data collected during routine hydroacoustic biomass assessments in the frame of Baltic International Acoustic Survey (BIAS) cruises. This technique incorporates a novel backscattering model, improving the accuracy of backscattering predictions for Baltic herring. \nThe orientation distributions for herring escaping from the vessel during the herring biomass estimation have been defined. The approach provides a more detailed interpretation of acoustic data, facilitates the characterization of Baltic herring, and enables the assessment of herring responses to passing research vessels.
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- Corresponding author: Mr Aleksander Żytko
Affiliation: Institute of Oceanology PAS
Country: Poland
