Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties
The oceanic mesopelagic zone, 200–1000 m below sea level, holds abundant small fishes that play central roles in ecosystem function. Global mesopelagic fish biomass estimates are increasingly derived using active acoustics, where echosounder-generated signals are emitted, reflected by pelagic organi...
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ftnerc:oai:nora.nerc.ac.uk:529957 2023-05-15T13:41:45+02:00 Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties Dornan, Tracey Fielding, Sophie Saunders, Ryan A. Genner, Martin J. 2022-01-26 text http://nora.nerc.ac.uk/id/eprint/529957/ https://nora.nerc.ac.uk/id/eprint/529957/1/rspb.2021.1781.pdf https://royalsocietypublishing.org/doi/10.1098/rspb.2021.1781 en eng Royal Society https://nora.nerc.ac.uk/id/eprint/529957/1/rspb.2021.1781.pdf Dornan, Tracey orcid:0000-0001-8265-286X Fielding, Sophie orcid:0000-0002-3152-4742 Saunders, Ryan A. orcid:0000-0002-1157-7222 Genner, Martin J. 2022 Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties. Proceedings of the Royal Society of London, B, 289 (1967). https://doi.org/10.1098/rspb.2021.1781 <https://doi.org/10.1098/rspb.2021.1781> cc_by_4 CC-BY Publication - Article PeerReviewed 2022 ftnerc https://doi.org/10.1098/rspb.2021.1781 2023-02-04T19:51:53Z The oceanic mesopelagic zone, 200–1000 m below sea level, holds abundant small fishes that play central roles in ecosystem function. Global mesopelagic fish biomass estimates are increasingly derived using active acoustics, where echosounder-generated signals are emitted, reflected by pelagic organisms and detected by transducers on vessels. Previous studies have interpreted a ubiquitous decline in acoustic reflectance towards the Antarctic continent as a reduction in mesopelagic fish biomass. Here, we use empirical data to estimate species-specific acoustic target strength for the dominant mesopelagic fish of the Scotia Sea in the Southern Ocean. We use these data, alongside estimates of fish relative abundance from net surveys, to interpret signals received in acoustic surveys and calculate mesopelagic biomass of the broader Southern Ocean. We estimate the Southern Ocean mesopelagic fish biomass to be approximately 274 million tonnes if Antarctic krill contribute to the acoustic signal, or 570 million tonnes if mesopelagic fish alone are responsible. These quantities are approximately 1.8 and 3.8 times greater than previous net-based biomass estimates. We also show a peak in fish biomass towards the seasonal ice-edge, corresponding to the preferred feeding grounds of penguins and seals, which may be at risk under future climate change scenarios. Our study provides new insights into the abundance and distributions of ecologically significant mesopelagic fish stocks across the Southern Ocean ecosystem. Article in Journal/Newspaper Antarc* Antarctic Antarctic Krill Scotia Sea Southern Ocean Natural Environment Research Council: NERC Open Research Archive Antarctic Scotia Sea Southern Ocean The Antarctic Proceedings of the Royal Society B: Biological Sciences 289 1967 |
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Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
language |
English |
description |
The oceanic mesopelagic zone, 200–1000 m below sea level, holds abundant small fishes that play central roles in ecosystem function. Global mesopelagic fish biomass estimates are increasingly derived using active acoustics, where echosounder-generated signals are emitted, reflected by pelagic organisms and detected by transducers on vessels. Previous studies have interpreted a ubiquitous decline in acoustic reflectance towards the Antarctic continent as a reduction in mesopelagic fish biomass. Here, we use empirical data to estimate species-specific acoustic target strength for the dominant mesopelagic fish of the Scotia Sea in the Southern Ocean. We use these data, alongside estimates of fish relative abundance from net surveys, to interpret signals received in acoustic surveys and calculate mesopelagic biomass of the broader Southern Ocean. We estimate the Southern Ocean mesopelagic fish biomass to be approximately 274 million tonnes if Antarctic krill contribute to the acoustic signal, or 570 million tonnes if mesopelagic fish alone are responsible. These quantities are approximately 1.8 and 3.8 times greater than previous net-based biomass estimates. We also show a peak in fish biomass towards the seasonal ice-edge, corresponding to the preferred feeding grounds of penguins and seals, which may be at risk under future climate change scenarios. Our study provides new insights into the abundance and distributions of ecologically significant mesopelagic fish stocks across the Southern Ocean ecosystem. |
format |
Article in Journal/Newspaper |
author |
Dornan, Tracey Fielding, Sophie Saunders, Ryan A. Genner, Martin J. |
spellingShingle |
Dornan, Tracey Fielding, Sophie Saunders, Ryan A. Genner, Martin J. Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties |
author_facet |
Dornan, Tracey Fielding, Sophie Saunders, Ryan A. Genner, Martin J. |
author_sort |
Dornan, Tracey |
title |
Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties |
title_short |
Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties |
title_full |
Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties |
title_fullStr |
Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties |
title_full_unstemmed |
Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties |
title_sort |
large mesopelagic fish biomass in the southern ocean resolved by acoustic properties |
publisher |
Royal Society |
publishDate |
2022 |
url |
http://nora.nerc.ac.uk/id/eprint/529957/ https://nora.nerc.ac.uk/id/eprint/529957/1/rspb.2021.1781.pdf https://royalsocietypublishing.org/doi/10.1098/rspb.2021.1781 |
geographic |
Antarctic Scotia Sea Southern Ocean The Antarctic |
geographic_facet |
Antarctic Scotia Sea Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctic Krill Scotia Sea Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Krill Scotia Sea Southern Ocean |
op_relation |
https://nora.nerc.ac.uk/id/eprint/529957/1/rspb.2021.1781.pdf Dornan, Tracey orcid:0000-0001-8265-286X Fielding, Sophie orcid:0000-0002-3152-4742 Saunders, Ryan A. orcid:0000-0002-1157-7222 Genner, Martin J. 2022 Large mesopelagic fish biomass in the Southern Ocean resolved by acoustic properties. Proceedings of the Royal Society of London, B, 289 (1967). https://doi.org/10.1098/rspb.2021.1781 <https://doi.org/10.1098/rspb.2021.1781> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1098/rspb.2021.1781 |
container_title |
Proceedings of the Royal Society B: Biological Sciences |
container_volume |
289 |
container_issue |
1967 |
_version_ |
1766157353772646400 |