The application of CW and FM sonar technology to detect a decrease in air in the swim bladder of Atlantic salmon, measurements and modeling
Salmon lice and poor surface conditions are challenging for salmon aquaculture. A new innovative preventative solution is to submerge the cages below the sea surface to avoid the surface-dwelling infestation of lice larvae. However, the physostomous salmon require daily surface access, or the swim b...
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The University of Bergen
2022
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ftunivbergen:oai:bora.uib.no:11250/3000819 2023-05-15T15:32:57+02:00 The application of CW and FM sonar technology to detect a decrease in air in the swim bladder of Atlantic salmon, measurements and modeling Rong, Maren Forstrønen 2022-06-22T22:00:28Z application/pdf https://hdl.handle.net/11250/3000819 eng eng The University of Bergen https://hdl.handle.net/11250/3000819 Copyright the Author. All rights reserved salmon submerged cages Acoustics aquaculture broadband and narrowband signals 752999 Master thesis 2022 ftunivbergen 2023-03-14T17:44:00Z Salmon lice and poor surface conditions are challenging for salmon aquaculture. A new innovative preventative solution is to submerge the cages below the sea surface to avoid the surface-dwelling infestation of lice larvae. However, the physostomous salmon require daily surface access, or the swim bladder will deflate. The ensues negative buoyancy leads to increased swimming speed, and over a prolonged time (2-3 weeks), the appetite and growth rate may be reduced, resulting in poor welfare. For 28 days, 500 salmon were placed in a cage submerged to 1 m depth, preventing the salmon from reaching the sea surface and refilling the swim bladder. Beneath the cage, three EK80 scientific wide-band echo sounders with 70, 120, and 200 kHz split-beam transducers were deployed to study the acoustic backscatter over time. From the backscattered signals, parameters such as the target strength (TS), volume backscattering strength (S_V), the frequency response of both TS and S_V, and the swimming speed could be calculated. These parameters are studied to determine the first to indicate an insufficient air level based on signal type and frequency. The results show an increase in swimming speed and a decrease in both TS and S_V values. From the measured daily TS values from both FM and CW signals, the decrease appeared to begin from day 6 of submergence. As the air in the bladder diminished, the ratio between the values from the three echo sounders increased, which was evident from TS and S_V measurements, and the frequency responses. The swimming speed acquired from the acoustical recordings decreased from day 5, but the speeds were unexpectedly high. These findings may be used to develop automatic alarms that detect low swim bladder inflations or poor welfare and provide new fundamental knowledge about backscattering from salmon. Masteroppgave i havteknologi HTEK399 MAMN-HTEK 5MAMN-HTEK Master Thesis Atlantic salmon University of Bergen: Bergen Open Research Archive (BORA-UiB) |
institution |
Open Polar |
collection |
University of Bergen: Bergen Open Research Archive (BORA-UiB) |
op_collection_id |
ftunivbergen |
language |
English |
topic |
salmon submerged cages Acoustics aquaculture broadband and narrowband signals 752999 |
spellingShingle |
salmon submerged cages Acoustics aquaculture broadband and narrowband signals 752999 Rong, Maren Forstrønen The application of CW and FM sonar technology to detect a decrease in air in the swim bladder of Atlantic salmon, measurements and modeling |
topic_facet |
salmon submerged cages Acoustics aquaculture broadband and narrowband signals 752999 |
description |
Salmon lice and poor surface conditions are challenging for salmon aquaculture. A new innovative preventative solution is to submerge the cages below the sea surface to avoid the surface-dwelling infestation of lice larvae. However, the physostomous salmon require daily surface access, or the swim bladder will deflate. The ensues negative buoyancy leads to increased swimming speed, and over a prolonged time (2-3 weeks), the appetite and growth rate may be reduced, resulting in poor welfare. For 28 days, 500 salmon were placed in a cage submerged to 1 m depth, preventing the salmon from reaching the sea surface and refilling the swim bladder. Beneath the cage, three EK80 scientific wide-band echo sounders with 70, 120, and 200 kHz split-beam transducers were deployed to study the acoustic backscatter over time. From the backscattered signals, parameters such as the target strength (TS), volume backscattering strength (S_V), the frequency response of both TS and S_V, and the swimming speed could be calculated. These parameters are studied to determine the first to indicate an insufficient air level based on signal type and frequency. The results show an increase in swimming speed and a decrease in both TS and S_V values. From the measured daily TS values from both FM and CW signals, the decrease appeared to begin from day 6 of submergence. As the air in the bladder diminished, the ratio between the values from the three echo sounders increased, which was evident from TS and S_V measurements, and the frequency responses. The swimming speed acquired from the acoustical recordings decreased from day 5, but the speeds were unexpectedly high. These findings may be used to develop automatic alarms that detect low swim bladder inflations or poor welfare and provide new fundamental knowledge about backscattering from salmon. Masteroppgave i havteknologi HTEK399 MAMN-HTEK 5MAMN-HTEK |
format |
Master Thesis |
author |
Rong, Maren Forstrønen |
author_facet |
Rong, Maren Forstrønen |
author_sort |
Rong, Maren Forstrønen |
title |
The application of CW and FM sonar technology to detect a decrease in air in the swim bladder of Atlantic salmon, measurements and modeling |
title_short |
The application of CW and FM sonar technology to detect a decrease in air in the swim bladder of Atlantic salmon, measurements and modeling |
title_full |
The application of CW and FM sonar technology to detect a decrease in air in the swim bladder of Atlantic salmon, measurements and modeling |
title_fullStr |
The application of CW and FM sonar technology to detect a decrease in air in the swim bladder of Atlantic salmon, measurements and modeling |
title_full_unstemmed |
The application of CW and FM sonar technology to detect a decrease in air in the swim bladder of Atlantic salmon, measurements and modeling |
title_sort |
application of cw and fm sonar technology to detect a decrease in air in the swim bladder of atlantic salmon, measurements and modeling |
publisher |
The University of Bergen |
publishDate |
2022 |
url |
https://hdl.handle.net/11250/3000819 |
genre |
Atlantic salmon |
genre_facet |
Atlantic salmon |
op_relation |
https://hdl.handle.net/11250/3000819 |
op_rights |
Copyright the Author. All rights reserved |
_version_ |
1766363431155269632 |