The Barents Sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass
Abstract Sampling of euphausiids is difficult because of their intermediate size between macrozooplankton and micronekton. The Barents Sea is one of the few marine areas where there have been long-term studies of euphausiids. We have examined three monitoring datasets on euphausiids and consider lik...
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croxfordunivpr:10.1093/icesjms/fsw022 2024-05-19T07:38:08+00:00 The Barents Sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass Eriksen, Elena Skjoldal, Hein Rune Dolgov, Andrey V. Dalpadado, Padmini Orlova, Emma L. Prozorkevich, Dmitry V. 2016 http://dx.doi.org/10.1093/icesjms/fsw022 http://academic.oup.com/icesjms/article-pdf/73/6/1533/31231440/fsw022.pdf en eng Oxford University Press (OUP) ICES Journal of Marine Science volume 73, issue 6, page 1533-1544 ISSN 1095-9289 1054-3139 journal-article 2016 croxfordunivpr https://doi.org/10.1093/icesjms/fsw022 2024-05-02T09:29:00Z Abstract Sampling of euphausiids is difficult because of their intermediate size between macrozooplankton and micronekton. The Barents Sea is one of the few marine areas where there have been long-term studies of euphausiids. We have examined three monitoring datasets on euphausiids and consider likely sources of errors associated with the sampling. Results indicated a high degree of patchiness in the distribution of euphausiids, even at the largest scale of sampling with a pelagic trawl. This indicates that euphausiids may occur in large, but infrequent, swarms that have a low probability of being sampled by small nets. The mean biomass of euphausiids sampled with MOCNESS was 2 g wet weight m−2 integrated over the water column, which is an underestimate due to avoidance of large individuals. The mean biomass obtained with pelagic trawl in the upper 60 m of water at night during an autumn survey was 10 g wet weight m−2. The plankton net on bottom trawl collected mean and median density of euphausiids (0.1–0.2 g wet weight m−3) near bottom during a winter survey similar to the values found with pelagic trawl in the upper layer during autumn. The mean density for the autumn survey showed an increase from 2000 to 2011, while the winter survey showed generally a decrease from 2000–2007 to 2011. The increase in the autumn series coincided with a general warming trend presumably with a larger influx of euphausiids with Atlantic water, notably of Meganyctiphanes norvegica. In contrast, the decline during winter may reflect a decrease, particularly of Thysanoessa raschii in the southeastern Barents Sea in the most recent years. Improvements in sampling gears combined with more and better use of acoustical and optical technologies offer great promise for improved monitoring and quantification of the roles of euphausiids in the Barents Sea ecosystem. Article in Journal/Newspaper Barents Sea Meganyctiphanes norvegica Thysanoessa raschii Oxford University Press ICES Journal of Marine Science 73 6 1533 1544 |
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Open Polar |
collection |
Oxford University Press |
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croxfordunivpr |
language |
English |
description |
Abstract Sampling of euphausiids is difficult because of their intermediate size between macrozooplankton and micronekton. The Barents Sea is one of the few marine areas where there have been long-term studies of euphausiids. We have examined three monitoring datasets on euphausiids and consider likely sources of errors associated with the sampling. Results indicated a high degree of patchiness in the distribution of euphausiids, even at the largest scale of sampling with a pelagic trawl. This indicates that euphausiids may occur in large, but infrequent, swarms that have a low probability of being sampled by small nets. The mean biomass of euphausiids sampled with MOCNESS was 2 g wet weight m−2 integrated over the water column, which is an underestimate due to avoidance of large individuals. The mean biomass obtained with pelagic trawl in the upper 60 m of water at night during an autumn survey was 10 g wet weight m−2. The plankton net on bottom trawl collected mean and median density of euphausiids (0.1–0.2 g wet weight m−3) near bottom during a winter survey similar to the values found with pelagic trawl in the upper layer during autumn. The mean density for the autumn survey showed an increase from 2000 to 2011, while the winter survey showed generally a decrease from 2000–2007 to 2011. The increase in the autumn series coincided with a general warming trend presumably with a larger influx of euphausiids with Atlantic water, notably of Meganyctiphanes norvegica. In contrast, the decline during winter may reflect a decrease, particularly of Thysanoessa raschii in the southeastern Barents Sea in the most recent years. Improvements in sampling gears combined with more and better use of acoustical and optical technologies offer great promise for improved monitoring and quantification of the roles of euphausiids in the Barents Sea ecosystem. |
format |
Article in Journal/Newspaper |
author |
Eriksen, Elena Skjoldal, Hein Rune Dolgov, Andrey V. Dalpadado, Padmini Orlova, Emma L. Prozorkevich, Dmitry V. |
spellingShingle |
Eriksen, Elena Skjoldal, Hein Rune Dolgov, Andrey V. Dalpadado, Padmini Orlova, Emma L. Prozorkevich, Dmitry V. The Barents Sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass |
author_facet |
Eriksen, Elena Skjoldal, Hein Rune Dolgov, Andrey V. Dalpadado, Padmini Orlova, Emma L. Prozorkevich, Dmitry V. |
author_sort |
Eriksen, Elena |
title |
The Barents Sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass |
title_short |
The Barents Sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass |
title_full |
The Barents Sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass |
title_fullStr |
The Barents Sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass |
title_full_unstemmed |
The Barents Sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass |
title_sort |
barents sea euphausiids: methodological aspects of monitoring and estimation of abundance and biomass |
publisher |
Oxford University Press (OUP) |
publishDate |
2016 |
url |
http://dx.doi.org/10.1093/icesjms/fsw022 http://academic.oup.com/icesjms/article-pdf/73/6/1533/31231440/fsw022.pdf |
genre |
Barents Sea Meganyctiphanes norvegica Thysanoessa raschii |
genre_facet |
Barents Sea Meganyctiphanes norvegica Thysanoessa raschii |
op_source |
ICES Journal of Marine Science volume 73, issue 6, page 1533-1544 ISSN 1095-9289 1054-3139 |
op_doi |
https://doi.org/10.1093/icesjms/fsw022 |
container_title |
ICES Journal of Marine Science |
container_volume |
73 |
container_issue |
6 |
container_start_page |
1533 |
op_container_end_page |
1544 |
_version_ |
1799477533123543040 |