# Species identification of fish shoals combining multibeam and split-beam echosounders with visual observations from diving [résumé]

Viviane David, Corentin Minart, Anne Mouget, Yannick Perrot, Pierre Thiriet, Éric Feunteun, Adrien Cheminée, Loïc Le Goff, Anthony Acou,

Patrice Brehmer

► To cite this version:

Viviane David, Corentin Minart, Anne Mouget, Yannick Perrot, Pierre Thiriet, et al.. Species iden-
tification of fish shoals combining multibeam and split-beam echosounders with visual observations
from diving [résumé]. ICES Scientifics Reports, 2022, 4 (54), pp.45-46. mnhn-04153959v2

HAL Id: mnhn-04153959

https://mnhn.hal.science/mnhn-04153959v2

Submitted on 14 Feb 2024

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# Species identification of fish shoals combining multibeam and split-beam echosounders with visual observations from diving [résumé]

Viviane David, Corentin Minart, Anne Mouget, Yannick Perrot, Pierre D Thiriet, Éric Feunteun, Adrien Cheminée, Loïc Le Goff, Anthony Acou, Patrice Brehmer

<figure><img src="image_1.png" /></figure>

## To cite this version:

Viviane David, Corentin Minart, Anne Mouget, Yannick Perrot, Pierre D Thiriet, et al. Species identification of fish shoals combining multibeam and split-beam echosounders with visual observations from diving [résumé]. ICES Scientifics Reports, 2022, 4 (54), pp.45-46. mnhn-04153959v2

HAL Id: mnhn-04153959

https://mnhn.hal.science/mnhn-04153959v2

Submitted on 14 Feb 2024

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Public Domain
pandemic, limits on personnel; furthermore, they struggle to get close to certain habitats, partic-
ularly man-made marine structures such as oil and gas platforms and offshore windfarms. Here
we present experience of an uncrewed surface vehicle (USV) survey of these habitats. We focus
on some of the challenges and benefits of the USV and describe how it was operated remotely
from the desk of navigators and sensor operators. Notable benefits include, in-situ calibration,
getting very close to certain platforms, surveying straight through an offshore windfarm, and
obtaining ancillary data such as regular 360° imagery for seabird detection. Challenges include
the lack of alternative evidence for the acoustic data, acoustic noise at longer ranges and some-
what limited survey range. However, these challenges are not unsurmountable, so prospects
for USV applications look good.

Recognizing the Influence of Turbulence-Induced Entrained Air When Monitoring for Risk to Fish at Ocean Energy Installations

Louise P. McGarry<fnref n="1" />, Haley A. Viehman<fnref n="2" />, Jessica Douglas<fnref n="1" />, and Daniel J. Hasselman<fnref n="1" />

For those tidal energy installations where it is required to quantify the potential risk to fish posed
by the introduction of energy conversion devices into the habitat, scientific hydroacoustic echo-
sounders provide quantifiable, stratified sampling of the whole water column with sufficiently
high resolution in time and space. However, the impressive currents that are favourable to en-
ergy development are often turbulent and result in air entrainment into the water column. En-
trained air limits the use of acoustic-based sampling systems to only those portions of the water
column not contaminated with entrained air. To help regulators and developers recognize the
potential implications to the understanding of fish presence, distribution, and abundance in
ocean energy sites, we undertook a study of the proportion of water column obfuscated by en-
trained air as a function of tide direction, current speed, and season. Our findings demonstrate
that site-specific localized hydrodynamics and seasonal winds can have a major impact on the
observable portion of the water column. This information is critical for determining an optimal
data collection site, establishing reasonable monitoring goals in dialogue with regulators, devel-
opers, and stakeholders, and for identifying periods of time when active acoustic technologies
may not be an effective tool for monitoring.

Species identification of fish shoals combining multibeam and split-beam echo-
sounders with visual observations from diving

Viviane David<fnref n="1" />,<fnref n="2" />*, Corentin Minart<fnref n="1" />,<fnref n="2" />, Anne Mouget<fnref n="3" />,<fnref n="4" />, Yannick Perrot<fnref n="2" />, Pierre Thiriet<fnref n="1" />, Eric Feun-
teun<fnref n="3" />,<fnref n="4" />, Adrien Cheminée⁵, Loïc Le Goff<fnref n="1" />, Anthony Acou<fnref n="1" />, Patrice Brehmer<fnref n="2" />

<footnote n="1">¹Fundy Ocean Research Centre for Energy (FORCE), 75 Alderney Drive, Dartmouth, Nova Scotia B2Y 2N7 Canada, louise.mcgarry@fundyforce.ca, jessica.douglas@fundyforce.ca, dan.hasselman@fundyforce.ca</footnote>

<footnote n="2">²Echoview Software Pty Ltd., GPO Box 1387, Hobart, Tasmania 7001, Australia, haley.viehman@echoview.com</footnote>

<footnote n="1">¹ *PatriNat* (OFB, CNRS, MNHN) – *Centre de d'expertise et de données sur la nature* – *Station Marine de Dinard, CRESCO, 38 rue de Port Blanc, Dinard, France*</footnote>

<footnote n="2">²IRD, Univ Brest, CNRS, Ifremer, UMR Lemar, Plouzané, France</footnote>

<footnote n="3">³ Laboratoire BOREA (Museum National d'Histoire Naturelle, CNRS, Sorbonne Université, IRD, Uni-
Caen, Univ Antilles Guadeloupe), 57 rue de cuvier, 75005 Paris, France</footnote>

<footnote n="4">⁴ Station Marine de Dinard, CRESCO, 38, rue du port Blanc, 35800 Dinard, France</footnote>
pandemic, limits on personnel; furthermore, they struggle to get close to certain habitats, partic-
ularly man-made marine structures such as oil and gas platforms and offshore windfarms. Here
we present experience of an uncrewed surface vehicle (USV) survey of these habitats. We focus
on some of the challenges and benefits of the USV and describe how it was operated remotely
from the desk of navigators and sensor operators. Notable benefits include, in-situ calibration,
getting very close to certain platforms, surveying straight through an offshore windfarm, and
obtaining ancillary data such as regular 360° imagery for seabird detection. Challenges include
the lack of alternative evidence for the acoustic data, acoustic noise at longer ranges and some-
what limited survey range. However, these challenges are not unsurmountable, so prospects
for USV applications look good.

Recognizing the Influence of Turbulence-Induced Entrained Air When Monitoring for Risk to Fish at Ocean Energy Installations

Louise P. McGarry<fnref n="1" />, Haley A. Viehman<fnref n="2" />, Jessica Douglas<fnref n="1" />, and Daniel J. Hasselman<fnref n="1" />

For those tidal energy installations where it is required to quantify the potential risk to fish posed
by the introduction of energy conversion devices into the habitat, scientific hydroacoustic echo-
sounders provide quantifiable, stratified sampling of the whole water column with sufficiently
high resolution in time and space. However, the impressive currents that are favourable to en-
ergy development are often turbulent and result in air entrainment into the water column. En-
trained air limits the use of acoustic-based sampling systems to only those portions of the water
column not contaminated with entrained air. To help regulators and developers recognize the
potential implications to the understanding of fish presence, distribution, and abundance in
ocean energy sites, we undertook a study of the proportion of water column obfuscated by en-
trained air as a function of tide direction, current speed, and season. Our findings demonstrate
that site-specific localized hydrodynamics and seasonal winds can have a major impact on the
observable portion of the water column. This information is critical for determining an optimal
data collection site, establishing reasonable monitoring goals in dialogue with regulators, devel-
opers, and stakeholders, and for identifying periods of time when active acoustic technologies
may not be an effective tool for monitoring.

Species identification of fish shoals combining multibeam and split-beam echo-
sounders with visual observations from diving

Viviane David<fnref n="1" />,<fnref n="2" />*, Corentin Minart<fnref n="1" />,<fnref n="2" />, Anne Mouget<fnref n="3" />,<fnref n="4" />, Yannick Perrot<fnref n="2" />, Pierre Thiriet<fnref n="1" />, Eric Feun-
teun<fnref n="3" />,<fnref n="4" />, Adrien Cheminée⁵, Loïc Le Goff<fnref n="1" />, Anthony Acou<fnref n="1" />, Patrice Brehmer<fnref n="2" />

<footnote n="1">¹Fundy Ocean Research Centre for Energy (FORCE), 75 Alderney Drive, Dartmouth, Nova Scotia B2Y 2N7 Canada, louise.mcgarry@fundyforce.ca, jessica.douglas@fundyforce.ca, dan.hasselman@fundyforce.ca</footnote>

<footnote n="2">²Echoview Software Pty Ltd., GPO Box 1387, Hobart, Tasmania 7001, Australia, haley.viehman@echoview.com</footnote>

<footnote n="1">¹ *PatriNat* (OFB, CNRS, MNHN) – *Centre de d'expertise et de données sur la nature* – *Station Marine de Dinard, CRESCO, 38 rue de Port Blanc, Dinard, France*</footnote>

<footnote n="2">²IRD, Univ Brest, CNRS, Ifremer, UMR Lemar, Plouzané, France</footnote>

<footnote n="3">³ Laboratoire BOREA (Museum National d'Histoire Naturelle, CNRS, Sorbonne Université, IRD, Uni-
Caen, Univ Antilles Guadeloupe), 57 rue de cuvier, 75005 Paris, France</footnote>

<footnote n="4">⁴ Station Marine de Dinard, CRESCO, 38, rue du port Blanc, 35800 Dinard, France</footnote>
⁵ *Septentrion Environnement, Campus Nature Provence, 89 Tra. Paragon, 13008, Marseille, France*

One challenge of acoustic observations of marine organisms is the identification of species, particularly in shallow waters where high diversity occurs. We deployed combining split-beam EK80 (70, 120 and 200 kHz) and M3 multibeam (500 kHz) echosounders to detect monospecific fish shoals in coastal shallow waters (5-60 m). Innovative protocols for the specific allocation were tested, using (i) a scuba divers census on fish shoals and (ii) a towed scuba diver. Stereoscopic video system was also used to assess fish length and abundance and compare with the visual estimations of divers. Several independent replicates of monospecific shoals from 5 fish species were obtained. The combined use of the echosounders allows to have complementary morphologic, acoustic and spatial descriptors to correctly discriminate the shoals. In addition, as the stereoscopic system has shown to provide precise measurements of individuals and could overcome the visual diver observations, our results suggest that a system equipped with cameras like a remotely controlled towed instrumentation platform could be used in a near future for ground trust in shallow and clear waters.

## Using histogram equalization to visualize acoustic and ancillary data

M. Peña<fnref n="1" />

¹Instituto Español de Oceanografía, Muelle de Poiente s/n Palma, Spain, marian.pena@ieo.es

Echogram visualization and processing is one of the most time-consuming tasks for fisheries acousticians. Analyzing target species or features is often based on experience while visualization settings are inherited from colleagues or established for standardization purposes within international efforts. Acoustic data is often visualized with a standard minimum threshold for Sv that varies with target species. For instance, small pelagic fishes are often visualized in European waters from - 60 dB re 1 m2 m-3 while echograms of the mesopelagic zone (200-1000 m depth) usually employ a -90 or -80 dB re 1 m2 m-3 minimum threshold. However, numerical volume density changes greatly with depth (particularly beyond the shelf), time of the day and season, and thus setting an incorrect threshold may mask part of the population at some times or areas. Following on Blackwell et al. (2019) that showed the best colormaps to be employed in fisheries acoustics, this presentation focus on further parameters (general thresholds and location of the color limits) of the colorbar. Most colormaps employ linear relationship between data and color, where every color represents a similar range of values. This can hide interesting features in only one or two colors. Histogram equalization is a non-linear interpolation technique that locates thresholds and color limits at the quantiles of the image data. Examples using acoustic and ancillary data will be shown to highlight the benefits of this technique. While no definite conclusion is provided, some food for thought on the influence of the number of colors employed will also be provided.

## Target classification of individual zooplankton in ex-situ broadband acoustic data using supervised machine learning

C. McGowan-Yallop<fnref n="1" />, K. Last<fnref n="2" />, F. Cottier<fnref n="3" />, S. Fielding<fnref n="4" /> and A.S. Brierley⁵

<footnote n="1">¹Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK, chelsey.mcgowan-yallop@sams.ac.uk,</footnote>

<footnote n="2">²Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK, kim.last@sams.ac.uk,</footnote>

<footnote n="3">³Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK, finlo.cottier@sams.ac.uk,</footnote>

<footnote n="4">⁴British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK, sof@bas.ac.uk,</footnote>
⁵ *Septentrion Environnement, Campus Nature Provence, 89 Tra. Paragon, 13008, Marseille, France*

One challenge of acoustic observations of marine organisms is the identification of species, particularly in shallow waters where high diversity occurs. We deployed combining split-beam EK80 (70, 120 and 200 kHz) and M3 multibeam (500 kHz) echosounders to detect monospecific fish shoals in coastal shallow waters (5-60 m). Innovative protocols for the specific allocation were tested, using (i) a scuba divers census on fish shoals and (ii) a towed scuba diver. Stereoscopic video system was also used to assess fish length and abundance and compare with the visual estimations of divers. Several independent replicates of monospecific shoals from 5 fish species were obtained. The combined use of the echosounders allows to have complementary morphologic, acoustic and spatial descriptors to correctly discriminate the shoals. In addition, as the stereoscopic system has shown to provide precise measurements of individuals and could overcome the visual diver observations, our results suggest that a system equipped with cameras like a remotely controlled towed instrumentation platform could be used in a near future for ground trust in shallow and clear waters.

## Using histogram equalization to visualize acoustic and ancillary data

M. Peña<fnref n="1" />

¹Instituto Español de Oceanografía, Muelle de Poiente s/n Palma, Spain, marian.pena@ieo.es

Echogram visualization and processing is one of the most time-consuming tasks for fisheries acousticians. Analyzing target species or features is often based on experience while visualization settings are inherited from colleagues or established for standardization purposes within international efforts. Acoustic data is often visualized with a standard minimum threshold for Sv that varies with target species. For instance, small pelagic fishes are often visualized in European waters from - 60 dB re 1 m2 m-3 while echograms of the mesopelagic zone (200-1000 m depth) usually employ a -90 or -80 dB re 1 m2 m-3 minimum threshold. However, numerical volume density changes greatly with depth (particularly beyond the shelf), time of the day and season, and thus setting an incorrect threshold may mask part of the population at some times or areas. Following on Blackwell et al. (2019) that showed the best colormaps to be employed in fisheries acoustics, this presentation focus on further parameters (general thresholds and location of the color limits) of the colorbar. Most colormaps employ linear relationship between data and color, where every color represents a similar range of values. This can hide interesting features in only one or two colors. Histogram equalization is a non-linear interpolation technique that locates thresholds and color limits at the quantiles of the image data. Examples using acoustic and ancillary data will be shown to highlight the benefits of this technique. While no definite conclusion is provided, some food for thought on the influence of the number of colors employed will also be provided.

## Target classification of individual zooplankton in ex-situ broadband acoustic data using supervised machine learning

C. McGowan-Yallop<fnref n="1" />, K. Last<fnref n="2" />, F. Cottier<fnref n="3" />, S. Fielding<fnref n="4" /> and A.S. Brierley⁵

<footnote n="1">¹Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK, chelsey.mcgowan-yallop@sams.ac.uk,</footnote>

<footnote n="2">²Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK, kim.last@sams.ac.uk,</footnote>

<footnote n="3">³Scottish Association for Marine Science, Oban, Argyll, PA37 1QA, UK, finlo.cottier@sams.ac.uk,</footnote>

<footnote n="4">⁴British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK, sof@bas.ac.uk,</footnote>
WORKING GROUP OF FISHERIES ACOUSTICS,
SCIENCE AND TECHNOLOGY (WGFAST)

VOLUME 4 | ISSUE 54

ICES SCIENTIFIC REPORTS

RAPPORTS

SCIENTIFIQUES DU CIEM

<figure><img src="image_1.png" /></figure>

ICES
CIEM

INTERNATIONAL COUNCIL FOR THE EXPLORATION OF THE SEA
CONSEIL INTERNATIONAL POUR L'EXPLORATION DE LA MER
WORKING GROUP OF FISHERIES ACOUSTICS,
SCIENCE AND TECHNOLOGY (WGFAST)

VOLUME 4 | ISSUE 54

ICES SCIENTIFIC REPORTS

RAPPORTS

SCIENTIFIQUES DU CIEM

<figure><img src="image_2.png" /></figure>

ICES
CIEM

INTERNATIONAL COUNCIL FOR THE EXPLORATION OF THE SEA
CONSEIL INTERNATIONAL POUR L'EXPLORATION DE LA MER
International Council for the Exploration of the Sea
Conseil International pour l'Exploration de la Mer

H.C. Andersens Boulevard 44-46

DK-1553 Copenhagen V

Denmark

Telephone (+45) 33 38 67 00

Telefax (+45) 33 93 42 15

www.ices.dk

info@ices.dk

ISSN number: 2618-1371

This document has been produced under the auspices of an ICES Expert Group or Committee. The
contents therein do not necessarily represent the view of the Council.

© 2022 International Council for the Exploration of the Sea

This work is licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0). For
citation of datasets or conditions for use of data to be included in other databases, please refer to ICES
data policy.

<figure><img src="image_2.png" /></figure>
International Council for the Exploration of the Sea
Conseil International pour l'Exploration de la Mer

H.C. Andersens Boulevard 44-46

DK-1553 Copenhagen V

Denmark

Telephone (+45) 33 38 67 00

Telefax (+45) 33 93 42 15

www.ices.dk

info@ices.dk

ISSN number: 2618-1371

This document has been produced under the auspices of an ICES Expert Group or Committee. The
contents therein do not necessarily represent the view of the Council.

© 2022 International Council for the Exploration of the Sea

This work is licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0). For
citation of datasets or conditions for use of data to be included in other databases, please refer to ICES
data policy.

<figure><img src="image_3.png" /></figure>
ICES Scientific Reports

Volume 4 | Issue 54

WORKING GROUP OF FISHERIES ACOUSTICS, SCIENCE AND TECHNOLOGY
(WGFAST)

Recommended format for purpose of citation:

ICES. 2022. Working Group of Fisheries Acoustics, Science and Technology (WGFAST).
ICES Scientific Reports. 4:54. 93 pp. https://doi.org/10.17895/ices.pub.20178464

Editor

Michael Jech

Author

Michael Jech
ICES Scientific Reports

Volume 4 | Issue 54

WORKING GROUP OF FISHERIES ACOUSTICS, SCIENCE AND TECHNOLOGY
(WGFAST)

Recommended format for purpose of citation:

ICES. 2022. Working Group of Fisheries Acoustics, Science and Technology (WGFAST).
ICES Scientific Reports. 4:54. 93 pp. https://doi.org/10.17895/ices.pub.20178464

Editor

Michael Jech

Author

Michael Jech