2025_programme: Uncrewed Surface Vehicles and fisheries acoustics: The Norwegian case

• Day: June 17, Tuesday
    Location / Time: B. ERATO at 10:10 - 10:30
• Last minutes changes: -
• Session: 25. Unmanned vehicles for underwater acoustic surveillance and monitoring
  Organiser(s): Alain Maguer
  Chairperson(s): Alain Maguer
• Lecture: Uncrewed Surface Vehicles and fisheries acoustics: The Norwegian case
  Paper ID: 2367
  Author(s): Nils Olav Handegard, Leif Edvard Bildøy, Espen Johnsen
  Presenter: Nils Olav Handegard
  Abstract: The Institute of Marine Research in Norway has started the transition from research vessel (RV) based monitoring of pelagic fish to utilizing uncrewed surface vehicles (USVs). Echosounders are used as the standard sensor for measuring fish abundance, and USVs can be instrumented with these sensors to collect the acoustic data. This reduces cost and allow us to increase the spatial and temporal coverage compared to conventional RVs. USVs are also less invasive and do not affect the natural fish behaviour to the same extent as an RVs.\nIn this presentation we detail how IMR envision to integrate USVs in their monitoring programs. Two different surveys are being used as test cases: The coastal sprat survey and the North Sea sandeel survey. \nThe ability to withstand prevailing weather conditions are important, both in terms of data quality and survivability. The maximum achievable signal-to-noise ratio is determined by the noise level of the platform and the acoustic properties of the target species, and determines the realistic depth ranges to reliably use echosounders quantitatively. This is especially relevant when using motorized vehicles since the engine is often located close to the sensors, making them more vulnerable to noise compared to wave, sail or buoyancy driven platforms. Data volumes may be large, especially when operating the echo sounders across a wide frequency range. Currently available bandwidths for data telemetry prevents us from transmitting the raw data. Data compression algorithms and target classification algorithms exist, and we are working on methods to deploy these on the USV and to telemeter the results to land-based remote operating centres.\nBiological sampling is currently the main bottleneck for a complete transition to autonomous operations. Samples are needed to estimate biological parameters based on age, maturity, and sample lengths. Currently USVs are not capable of taking physical samples, and traditional trawl sampling is still required. However, fisheries sampling can be used if the gear selectivity and target cohort do not deviate substantially from similar data from RVs.\nA remote operating centre has also been established to manage USV operations and ensure compliance with legal requirements.\n
• Corresponding author: Dr Nils Olav Handegard
  Affiliation: Institute of Marine Research
  Country: Norway