A novel upward-looking hydroacoustic method for improving pelagic fish surveys

0479879 - BC 2018 RIV GB eng J - Journal Article
Baran, Roman - Jůza, Tomáš - Tušer, Michal - Balk, Helge - Blabolil, Petr - Čech, Martin - Draštík, Vladislav - Frouzová, Jaroslava - Jayasinghe, Asanka D. - Koliada, Ievgen - Mrkvička, Tomáš - Muška, Milan - Ricard, Daniel - Sajdlová, Zuzana - Vejřík, Lukáš - Kubečka, Jan
A novel upward-looking hydroacoustic method for improving pelagic fish surveys.
Scientific Reports. Roč. 7, JUL (2017), č. článku 4823. ISSN 2045-2322. E-ISSN 2045-2322
R&D Projects: GA MŠMT(CZ) EE2.3.20.0204; GA MŠMT(CZ) EE2.3.30.0032
Institutional support: RVO:60077344
Keywords : horizontal acoustic surveys * target-strength * vertical-distribution * spatial-distribution * in-situ
OECD category: Marine biology, freshwater biology, limnology
Impact factor: 4.122, year: 2017

For ethical reasons and animal welfare, it is becoming increasingly more important to carry out ecological surveys with a non-invasive approach. Information about fish distribution and abundance in the upper water column is often fundamental. However, this information is extremely hard to obtain using classical hydroacoustic methods. We developed a rigid frame system for pushing upward looking transducers of the scientific echo sounder (38 and 120 kHz) in front of the research vessel. The efficiency of the new approach for monitoring juvenile fish at night was investigated by comparing the results with a quantitative fry trawl in the Rimov Reservoir in the Czech Republic. The experimental setup enabled comparisons for the 0-3 m and 3-6 m depth layers, which are utilized by almost all juvenile fish in summer. No statistically significant differences in the estimated abundance of juveniles were found between the two sampling methods. The comparison of abundance estimates gathered by the two frequencies were also not significantly different. The predicted mean lengths from acoustic sampling and the trawl catches differed by less than 10 mm in all comparisons. Results suggest that mobile hydroacoustic upward-looking systems can fill the methodological gap in non-invasive surveying of surface fishes.
Permanent Link: http://hdl.handle.net/11104/0275801