Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas
Thesis (M.S.) University of Alaska Fairbanks, 2020 Egg production and copepodite growth rates were measured for the calanoid copepods Pseudocalanus spp., Calanus marshallae/glacialis, and Metridia pacifica in the northern Bering and southern Chukchi Seas during June of 2017 and 2018. For all taxa, i...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/12317 2023-05-15T15:43:59+02:00 Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas Poje, Alexandra Hopcroft, Russ Coyle, Kenneth Danielson, Seth 2020-08 http://hdl.handle.net/11122/12317 en_US eng http://hdl.handle.net/11122/12317 Department of Oceanography Calanus marshallae Bering Sea Reproduction Chukchi Sea Calanus Metridinidae Pseudocalanidae Master of Science in Oceanography Thesis ms 2020 ftunivalaska 2023-02-23T21:37:53Z Thesis (M.S.) University of Alaska Fairbanks, 2020 Egg production and copepodite growth rates were measured for the calanoid copepods Pseudocalanus spp., Calanus marshallae/glacialis, and Metridia pacifica in the northern Bering and southern Chukchi Seas during June of 2017 and 2018. For all taxa, instantaneous growth rates generally decreased with increasing copepodite stage, though the differences between most stages was not significant. The growth rates for Pseudocalanus spp. averaged 0.03 ± 0.002 day⁻¹, Calanus spp. 0.09 ± 0.004 day⁻¹, and M. pacifica 0.05 ± 0.03 day⁻¹. Egg production rates increased with prosome length for all species, but when standardized to body weight this trend reversed. All Pseudocalanus species had similar weight-specific egg production (SEP): 0.18 ± 0.01 for P. acuspes, 0.15 ± 0.00 for P. newmani, and 0.11 ± 0.02 for P. minutus. The SEP for Calanus was considerably lower, 0.09 ± 0.01, while for M. pacifica it was 0.11 ± 0.01. These rates suggest considerable discrepancies between growth rates and egg production weights that we propose are due to differences in life history strategies. Pseudocalanus reproduce nearly year round, they appear to invest less in somatic growth, preferring to quickly reach their adult stage where they invest heavily into reproduction. Calanus spp. have 1 or possibly 2 generations per year in this region, they invest more into somatic growth in order to ensure their population is ready for a reproductive season timed to the spring phytoplankton bloom. The more omnivorous M. pacifica is also likely limited to 1 or 2 generations, although their ability to thrive on a wider range of food sources than Calanus seems to allow for relatively higher investment in reproduction and perhaps lower investment in somatic growth. Consistent with other studies, global growth models do not match our observations particularly well, likely because they are dominated by egg production estimates at lower latitudes. North Pacific Research Board Thesis Bering Sea Chukchi Chukchi Sea Alaska Copepods University of Alaska: ScholarWorks@UA Bering Sea Chukchi Sea Fairbanks Pacific |
institution |
Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
English |
topic |
Calanus marshallae Bering Sea Reproduction Chukchi Sea Calanus Metridinidae Pseudocalanidae Master of Science in Oceanography |
spellingShingle |
Calanus marshallae Bering Sea Reproduction Chukchi Sea Calanus Metridinidae Pseudocalanidae Master of Science in Oceanography Poje, Alexandra Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas |
topic_facet |
Calanus marshallae Bering Sea Reproduction Chukchi Sea Calanus Metridinidae Pseudocalanidae Master of Science in Oceanography |
description |
Thesis (M.S.) University of Alaska Fairbanks, 2020 Egg production and copepodite growth rates were measured for the calanoid copepods Pseudocalanus spp., Calanus marshallae/glacialis, and Metridia pacifica in the northern Bering and southern Chukchi Seas during June of 2017 and 2018. For all taxa, instantaneous growth rates generally decreased with increasing copepodite stage, though the differences between most stages was not significant. The growth rates for Pseudocalanus spp. averaged 0.03 ± 0.002 day⁻¹, Calanus spp. 0.09 ± 0.004 day⁻¹, and M. pacifica 0.05 ± 0.03 day⁻¹. Egg production rates increased with prosome length for all species, but when standardized to body weight this trend reversed. All Pseudocalanus species had similar weight-specific egg production (SEP): 0.18 ± 0.01 for P. acuspes, 0.15 ± 0.00 for P. newmani, and 0.11 ± 0.02 for P. minutus. The SEP for Calanus was considerably lower, 0.09 ± 0.01, while for M. pacifica it was 0.11 ± 0.01. These rates suggest considerable discrepancies between growth rates and egg production weights that we propose are due to differences in life history strategies. Pseudocalanus reproduce nearly year round, they appear to invest less in somatic growth, preferring to quickly reach their adult stage where they invest heavily into reproduction. Calanus spp. have 1 or possibly 2 generations per year in this region, they invest more into somatic growth in order to ensure their population is ready for a reproductive season timed to the spring phytoplankton bloom. The more omnivorous M. pacifica is also likely limited to 1 or 2 generations, although their ability to thrive on a wider range of food sources than Calanus seems to allow for relatively higher investment in reproduction and perhaps lower investment in somatic growth. Consistent with other studies, global growth models do not match our observations particularly well, likely because they are dominated by egg production estimates at lower latitudes. North Pacific Research Board |
author2 |
Hopcroft, Russ Coyle, Kenneth Danielson, Seth |
format |
Thesis |
author |
Poje, Alexandra |
author_facet |
Poje, Alexandra |
author_sort |
Poje, Alexandra |
title |
Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas |
title_short |
Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas |
title_full |
Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas |
title_fullStr |
Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas |
title_full_unstemmed |
Growth and reproductive rates of calanoid copepods in the northern Bering and southern Chukchi Seas |
title_sort |
growth and reproductive rates of calanoid copepods in the northern bering and southern chukchi seas |
publishDate |
2020 |
url |
http://hdl.handle.net/11122/12317 |
geographic |
Bering Sea Chukchi Sea Fairbanks Pacific |
geographic_facet |
Bering Sea Chukchi Sea Fairbanks Pacific |
genre |
Bering Sea Chukchi Chukchi Sea Alaska Copepods |
genre_facet |
Bering Sea Chukchi Chukchi Sea Alaska Copepods |
op_relation |
http://hdl.handle.net/11122/12317 Department of Oceanography |
_version_ |
1766378204716597248 |