Performance of a Low Cost Single Beam Echosounder: In Situ Trials in a Shallow Water Coral Reef Habitat with Verification by Video
Betanzos, A.; Martin, H.A.; Valle, S.; Schneider, P.; Hernandez, J.L.; Brehmer, P.; Tizol, R.; Linares, E.O.; Guillard, J.; Hermand, J.-P. (2015). Performance of a Low Cost Single Beam Echosounder: In Situ Trials in a Shallow Water Coral Reef Habitat with Verification by Video, in: 2015 IEEE/OES Acoustics in Underwater Geosciences Symposium. pp. 3. https://dx.doi.org/10.1109/RIOAcoustics.2015.7473629 In: (2015). 2015 IEEE/OES Acoustics in Underwater Geosciences Symposium. Institute of Electrical and Electronics Engineers: [s.l.]. ISBN 978-1-4673-7019-6. , more |
| Available in | Authors | | Document type: Conference paper
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| Keyword | | | Author keywords | echosounder; hydroacoustics; Simrad EK15; Biosonics DT-X; aggregation;spawning; video; coral reef; Cuba |
| Authors | | Top | - Betanzos, A.
- Martin, H.A.
- Valle, S.
- Schneider, P.
| - Hernandez, J.L.
- Brehmer, P.
- Tizol, R.
| - Linares, E.O.
- Guillard, J.
- Hermand, J.-P., more
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| Abstract | In a context of potential overexploitation of fisheries resources in the Sabana-Camaguey Archipelago (Cuba), the Cuban national authorities have expressed the need to collect more in situ information on fish of commercial interest in spawning areas. A newly developed low cost single-beam scientific echosounder has been recently acquired by the Cuban Fisheries Research Centre (CIP). In this work, we provide first results of a comparative analysis carried out in the Sabana-Camaguey Archipelago (Cuba), with the aim to evaluate the suitability of this type of echosounder as a tool for assessing fish aggregations in shallow waters. To this end, data acquired with the single-beam Simrad EK15 (200 kHz) have been compared with data acquired with a split-beam Biosonics DT-X (208 kHz), the latter representing the standard system for comparison. Both systems were calibrated following standard procedures and data have been analysed using Echoview software. The additional use of CCTV underwater video ("drop cam") allowed real-time monitoring of fish present in the study area. Identification of fish species was possible due to the low water turbidity in the coral habitat and was performed using either video images or observations by divers. Fish schools and spawning aggregations of Lutjanidae such as lane snapper (Lutjanus synagris) were observed. Target strength (TS) of individual fish was determined by using split-beam data of individuals from the edge of the school. Additionally, existing knowledge of TS of some major tropical fish species in Cuban waters provided the possibility to apply the regressions of TS versus size of fish and compare sizes with information available from fishermen in the area. A first synthesis of information available from all these different sources suggests the suitability of low-cost scientific echosounders as a tool to obtain valuable data on spawning aggregations on the Cuban shelf to depths of about 50 m. The use of a video system simultaneously with hydroacoustic methods in clear and shallow waters proves to be a useful ground-truth tool to improve the reliability of this kind of assessments. |
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