Hydroacoustic Autonomous boat for Remote fish detection in LakE (HARLE), an unmanned autonomous surface vehicle to monitor fish populations in lakes

Abstract

To evaluate the aquatic ecosystem's quality and ensure the sustainable management of fisheries, it is important to monitor fish populations. Hydroacoustics uses sound waves to noninvasively scan and gather information on waterbodies including fish abundance and distribution. Unmanned surface vehicles (USV) have been increasingly used in marine and freshwater environments to enable data collection. We provide a detailed description of a new USV called Hydroacoustic Autonomous boat for Remote fish detection in LakE (HARLE), which is devoted to hydroacoustic studies in freshwater. The USV is electrically powered and equipped with the most modern fishery scientific echosounder, suitable for broadband applications, the EK80 (SIMRAD). The USV was used for a conventional hydroacoustic survey in a peri-alpine lake to investigate its potential to monitor fish populations in lakes. In the lower layer of the lake where there were numerous targets and comparisons were possible, hydroacoustic metrics and fish biomass values (kg ha −1 ) from the SIMRAD EK80 on board the USV and EK60 on board the research vessel were similar. We showed that the HARLE has great potential to be used as a tool for fish monitoring and hydroacoustic survey in freshwater.

Global historical trends and drivers of submerged aquatic vegetation quantities in lakes

“…Additionally, these techniques are best suited in turbid waters as in these conditions, only reasonable SAV detection is achieved from object‐based image analysis and optic sensors are typically blind at only 1‐ or 2‐m depth (de Grandpré et al, 2022; Krause et al, 2021; Rowan & Kalacska, 2021). Sonar technology is also becoming more accessible including the use of unmanned boats (e.g., Goulon et al, 2021), with improved recreational‐grade sonars and automatic cloud‐based postprocessing (Buscombe, 2017; Helminen et al, 2019; Howell & Richardson, 2019) that will allow for greater aerial coverage, faster sampling, and reduced cost. Both optical and acoustic remote techniques are increasingly being used for the monitoring of seagrass changes (Gumusay et al, 2019; Veettil et al, 2020), and learning from these practices may help fast‐track their application to inland waters.…”

Combining quadrat, rake, and echosounding to estimate submerged aquatic vegetation biomass at the ecosystem scale

“…Recent echosounders also provide information on substrate type that can increase accuracy when applying our two‐step calibration approach (Munday et al 2013; Helminen et al 2019). New technological development in hydroacoustic autonomous boats (Goulon et al 2021) are further promising to reduce sampling time and increase sampling frequency. To confirm that the intercalibration we provide can be generalized, comparison of biomass techniques should additionally be conducted in other environments and using a diversity of apparatus such as different tools to sample SAV from the surface or echosounder frequencies.…”

Optimisation d’une méthode non intrusive de l’étude des populations de poissons en lac : l’hydro-acoustique

“…On peut ainsi obtenir des observations dans des zones difficiles à atteindre, répéter les acquisitions pour accroître le nombre d'informations, tant sur le plan spatial que temporel. Avec la collaboration de la société CT2MC, dans le cadre d'un projet financé par l'ADEME 3 , l'UMR CARRTEL a conçu un engin entièrement autonome appelé HARLE : Hydroacoustic Autonomous boat for Remote fish detection in LakE (Goulon et al, 2021). L'engin est alimenté électriquement et équipé de la dernière génération de sondeurs scientifiques (EK80).…”