Seasonal abundance, population structure, sex ratio and gonad maturation of Metridia okhotensis Brodsky, 1950 in the Okhotsk Sea: analysis of samples collected by pumping up from deep water
In the Okhotsk Sea, the calanoid copepod Metridia okhotensis Brodsky, 1950 is the dominant component of zooplankton, accounting for 61% of the annual mean total pelagic copepods. Although this organism is important, little ecological information is available for M. okhotensis in the Okhotsk Sea beca...
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crbrillap:10.1163/15685403-00003516 2024-04-07T07:55:12+00:00 Seasonal abundance, population structure, sex ratio and gonad maturation of Metridia okhotensis Brodsky, 1950 in the Okhotsk Sea: analysis of samples collected by pumping up from deep water Arima, Daichi Yamaguchi, Atsushi Nobetsu, Takahiro Imai, Ichiro 2016 http://dx.doi.org/10.1163/15685403-00003516 https://brill.com/view/journals/cr/89/2/article-p151_3.xml https://data.brill.com/files/journals/15685403_089_02_s003_text.pdf unknown Brill Crustaceana volume 89, issue 2, page 151-161 ISSN 0011-216X 1568-5403 Animal Science and Zoology Aquatic Science journal-article 2016 crbrillap https://doi.org/10.1163/15685403-00003516 2024-03-08T00:28:06Z In the Okhotsk Sea, the calanoid copepod Metridia okhotensis Brodsky, 1950 is the dominant component of zooplankton, accounting for 61% of the annual mean total pelagic copepods. Although this organism is important, little ecological information is available for M. okhotensis in the Okhotsk Sea because of the ice cover during winter, which prevents the collection of seasonal samples in this region. Here, we report the seasonal changes in the population structure, sex ratio and female gonad maturation of M. okhotensis . The data are from samples collected using water pumped from a depth of 350 m off Rausu Harbour in the Okhotsk Sea at 2-week intervals over a 2.5-year period. Due to the mesh size of the strainer (420 μm), M. okhotensis was collected from C3 to adults. The sex ratio of C5 (female : male) was approximately 1 : 1 throughout the year. In contrast, the sex ratio of C6 (adult) showed a clear seasonality, with males (C6M) occurring only from December to May and females (C6F) dominating during the other seasons. The gonad maturation of C6F was scored using five categories, and their composition also showed clear seasonality. From January to April, gonads developed rapidly from stage I (immature) to V (spawning). During the other seasons, the majority of C6F had immature gonads. Based on these data, we conclude that this species likely has a diapause phase for C6F, with immature gonads, and C5M from June to November. Moulting from C5M to C6M began in December. Accompanying the occurrence of C6M, C6F were fertilized from December to January. C6F underwent gonad maturation from January to April and performed primary reproduction from April to May. Thereafter, M. okhotensis entered diapause from June to November. Article in Journal/Newspaper okhotsk sea Copepods Brill Okhotsk Crustaceana 89 2 151 161 |
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Animal Science and Zoology Aquatic Science |
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Animal Science and Zoology Aquatic Science Arima, Daichi Yamaguchi, Atsushi Nobetsu, Takahiro Imai, Ichiro Seasonal abundance, population structure, sex ratio and gonad maturation of Metridia okhotensis Brodsky, 1950 in the Okhotsk Sea: analysis of samples collected by pumping up from deep water |
topic_facet |
Animal Science and Zoology Aquatic Science |
description |
In the Okhotsk Sea, the calanoid copepod Metridia okhotensis Brodsky, 1950 is the dominant component of zooplankton, accounting for 61% of the annual mean total pelagic copepods. Although this organism is important, little ecological information is available for M. okhotensis in the Okhotsk Sea because of the ice cover during winter, which prevents the collection of seasonal samples in this region. Here, we report the seasonal changes in the population structure, sex ratio and female gonad maturation of M. okhotensis . The data are from samples collected using water pumped from a depth of 350 m off Rausu Harbour in the Okhotsk Sea at 2-week intervals over a 2.5-year period. Due to the mesh size of the strainer (420 μm), M. okhotensis was collected from C3 to adults. The sex ratio of C5 (female : male) was approximately 1 : 1 throughout the year. In contrast, the sex ratio of C6 (adult) showed a clear seasonality, with males (C6M) occurring only from December to May and females (C6F) dominating during the other seasons. The gonad maturation of C6F was scored using five categories, and their composition also showed clear seasonality. From January to April, gonads developed rapidly from stage I (immature) to V (spawning). During the other seasons, the majority of C6F had immature gonads. Based on these data, we conclude that this species likely has a diapause phase for C6F, with immature gonads, and C5M from June to November. Moulting from C5M to C6M began in December. Accompanying the occurrence of C6M, C6F were fertilized from December to January. C6F underwent gonad maturation from January to April and performed primary reproduction from April to May. Thereafter, M. okhotensis entered diapause from June to November. |
format |
Article in Journal/Newspaper |
author |
Arima, Daichi Yamaguchi, Atsushi Nobetsu, Takahiro Imai, Ichiro |
author_facet |
Arima, Daichi Yamaguchi, Atsushi Nobetsu, Takahiro Imai, Ichiro |
author_sort |
Arima, Daichi |
title |
Seasonal abundance, population structure, sex ratio and gonad maturation of Metridia okhotensis Brodsky, 1950 in the Okhotsk Sea: analysis of samples collected by pumping up from deep water |
title_short |
Seasonal abundance, population structure, sex ratio and gonad maturation of Metridia okhotensis Brodsky, 1950 in the Okhotsk Sea: analysis of samples collected by pumping up from deep water |
title_full |
Seasonal abundance, population structure, sex ratio and gonad maturation of Metridia okhotensis Brodsky, 1950 in the Okhotsk Sea: analysis of samples collected by pumping up from deep water |
title_fullStr |
Seasonal abundance, population structure, sex ratio and gonad maturation of Metridia okhotensis Brodsky, 1950 in the Okhotsk Sea: analysis of samples collected by pumping up from deep water |
title_full_unstemmed |
Seasonal abundance, population structure, sex ratio and gonad maturation of Metridia okhotensis Brodsky, 1950 in the Okhotsk Sea: analysis of samples collected by pumping up from deep water |
title_sort |
seasonal abundance, population structure, sex ratio and gonad maturation of metridia okhotensis brodsky, 1950 in the okhotsk sea: analysis of samples collected by pumping up from deep water |
publisher |
Brill |
publishDate |
2016 |
url |
http://dx.doi.org/10.1163/15685403-00003516 https://brill.com/view/journals/cr/89/2/article-p151_3.xml https://data.brill.com/files/journals/15685403_089_02_s003_text.pdf |
geographic |
Okhotsk |
geographic_facet |
Okhotsk |
genre |
okhotsk sea Copepods |
genre_facet |
okhotsk sea Copepods |
op_source |
Crustaceana volume 89, issue 2, page 151-161 ISSN 0011-216X 1568-5403 |
op_doi |
https://doi.org/10.1163/15685403-00003516 |
container_title |
Crustaceana |
container_volume |
89 |
container_issue |
2 |
container_start_page |
151 |
op_container_end_page |
161 |
_version_ |
1795672195523936256 |