Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region
As a basis for analyzing development of six large grazing copepods (Eucalanus bungii, Metridia pacifica, M. okhotensis, Neocalanus cristatus, N. flemingeri and N. plumchrus) in the Oyashio region, quasi-daily twin-NORPAC net (0.33 and 0.10 mm mesh) hauls were taken through the upper 150 m and 500 m...
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/43806 2023-05-15T15:44:01+02:00 Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region Yamaguchi, Atsushi Onishi, Yuka Omata, Aya Kawai, Momoka Kaneda, Mariko Ikeda, Tsutomu http://hdl.handle.net/2115/43806 https://doi.org/10.1016/j.dsr2.2010.03.012 eng eng Elsevier http://hdl.handle.net/2115/43806 Deep Sea Research Part II: Topical Studies in Oceanography, 57(17-18): 1679-1690 http://dx.doi.org/10.1016/j.dsr2.2010.03.012 Copepods Egg production Gut pigment Life cycle OECOS 452 article (author version) fthokunivhus https://doi.org/10.1016/j.dsr2.2010.03.012 2022-11-18T01:02:02Z As a basis for analyzing development of six large grazing copepods (Eucalanus bungii, Metridia pacifica, M. okhotensis, Neocalanus cristatus, N. flemingeri and N. plumchrus) in the Oyashio region, quasi-daily twin-NORPAC net (0.33 and 0.10 mm mesh) hauls were taken through the upper 150 m and 500 m at a station southwest of Hokkaido before (9-14 March) and after (6-30 April) the onset of the phytoplankton bloom in 2007. Based on additional fresh specimens collected from 0-150 m, egg production of E. bungii, M. pacifica and M. okhotensis, and gut pigments of late copepodid stages in each species were evaluated. Total zooplankton biomass was greater from 10 April onward by a factor of 2- to 8-fold the previous levels. This increase of the 0-150 m biomass was caused by development of Neocalanus spp. copepodids and upward migration of resting E. bungii. Egg production of E. bungii peaked on 18 April, while abundance of its nauplii and C1 peaked on 20 and 25 April, respectively. Sex ratio and C6-female gonad maturation index of E. bungii showed new recruitment to C6 during 20-30 April, likely derived from a population that over-wintered as C3 or C4. Egg production and hatchability of M. pacifica and M. okhotensis were highly variable and no temporal trend was detected. Comparison with field abundance data for Metridia spp. suggests that our estimates of egg production and hatchability are too low, despite care with experimental conditions. All the Neocalanus species utilize the bloom as energy for juvenile growth. Neocalanus cristatus developed from C2 through C4, and stage duration of C3 was estimated to be 24 days. Neocalanus flemingeri also developed from Cl through C3, and stage durations of C1 and C2 were estimated to be 7-9 days. Neocalanus plumchrus occurred in small numbers from mid-April onward. The stage duration estimates for Neocalanus spp. are similar to those reported from the high-nutrition southeastern Bering Sea shelf. Gut pigment variation clearly showed nocturnal feeding by Metridia spp., while no ... Article in Journal/Newspaper Bering Sea Copepods Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Bering Sea Oyashio ENVELOPE(157.000,157.000,50.000,50.000) Deep Sea Research Part II: Topical Studies in Oceanography 57 17-18 1679 1690 |
institution |
Open Polar |
collection |
Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
op_collection_id |
fthokunivhus |
language |
English |
topic |
Copepods Egg production Gut pigment Life cycle OECOS 452 |
spellingShingle |
Copepods Egg production Gut pigment Life cycle OECOS 452 Yamaguchi, Atsushi Onishi, Yuka Omata, Aya Kawai, Momoka Kaneda, Mariko Ikeda, Tsutomu Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region |
topic_facet |
Copepods Egg production Gut pigment Life cycle OECOS 452 |
description |
As a basis for analyzing development of six large grazing copepods (Eucalanus bungii, Metridia pacifica, M. okhotensis, Neocalanus cristatus, N. flemingeri and N. plumchrus) in the Oyashio region, quasi-daily twin-NORPAC net (0.33 and 0.10 mm mesh) hauls were taken through the upper 150 m and 500 m at a station southwest of Hokkaido before (9-14 March) and after (6-30 April) the onset of the phytoplankton bloom in 2007. Based on additional fresh specimens collected from 0-150 m, egg production of E. bungii, M. pacifica and M. okhotensis, and gut pigments of late copepodid stages in each species were evaluated. Total zooplankton biomass was greater from 10 April onward by a factor of 2- to 8-fold the previous levels. This increase of the 0-150 m biomass was caused by development of Neocalanus spp. copepodids and upward migration of resting E. bungii. Egg production of E. bungii peaked on 18 April, while abundance of its nauplii and C1 peaked on 20 and 25 April, respectively. Sex ratio and C6-female gonad maturation index of E. bungii showed new recruitment to C6 during 20-30 April, likely derived from a population that over-wintered as C3 or C4. Egg production and hatchability of M. pacifica and M. okhotensis were highly variable and no temporal trend was detected. Comparison with field abundance data for Metridia spp. suggests that our estimates of egg production and hatchability are too low, despite care with experimental conditions. All the Neocalanus species utilize the bloom as energy for juvenile growth. Neocalanus cristatus developed from C2 through C4, and stage duration of C3 was estimated to be 24 days. Neocalanus flemingeri also developed from Cl through C3, and stage durations of C1 and C2 were estimated to be 7-9 days. Neocalanus plumchrus occurred in small numbers from mid-April onward. The stage duration estimates for Neocalanus spp. are similar to those reported from the high-nutrition southeastern Bering Sea shelf. Gut pigment variation clearly showed nocturnal feeding by Metridia spp., while no ... |
format |
Article in Journal/Newspaper |
author |
Yamaguchi, Atsushi Onishi, Yuka Omata, Aya Kawai, Momoka Kaneda, Mariko Ikeda, Tsutomu |
author_facet |
Yamaguchi, Atsushi Onishi, Yuka Omata, Aya Kawai, Momoka Kaneda, Mariko Ikeda, Tsutomu |
author_sort |
Yamaguchi, Atsushi |
title |
Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region |
title_short |
Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region |
title_full |
Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region |
title_fullStr |
Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region |
title_full_unstemmed |
Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region |
title_sort |
population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the oyashio region |
publisher |
Elsevier |
url |
http://hdl.handle.net/2115/43806 https://doi.org/10.1016/j.dsr2.2010.03.012 |
long_lat |
ENVELOPE(157.000,157.000,50.000,50.000) |
geographic |
Bering Sea Oyashio |
geographic_facet |
Bering Sea Oyashio |
genre |
Bering Sea Copepods |
genre_facet |
Bering Sea Copepods |
op_relation |
http://hdl.handle.net/2115/43806 Deep Sea Research Part II: Topical Studies in Oceanography, 57(17-18): 1679-1690 http://dx.doi.org/10.1016/j.dsr2.2010.03.012 |
op_doi |
https://doi.org/10.1016/j.dsr2.2010.03.012 |
container_title |
Deep Sea Research Part II: Topical Studies in Oceanography |
container_volume |
57 |
container_issue |
17-18 |
container_start_page |
1679 |
op_container_end_page |
1690 |
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1766378232604524544 |