On birth and death in the sea
We present the first comparative study of the stage-specific patterns of mortality of Calanus and Pseudocalanus, two widely distributed genera that are representative of a relatively large-bodied, broadcast spawning calanoid copepod and a relatively small-bodied, egg-brooding calanoid. The study sit...
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2002
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ftcdlib:oai:escholarship.org:ark:/13030/qt4f52v6ds 2023-06-18T03:40:05+02:00 On birth and death in the sea Ohman, Mark D Runge, Jeffrey A Durbin, Edward G Field, David B Niehoff, Barbara 55 - 68 2002-07-01 application/pdf https://escholarship.org/uc/item/4f52v6ds unknown eScholarship, University of California qt4f52v6ds https://escholarship.org/uc/item/4f52v6ds public Hydrobiologia, vol 480, iss 1-3 Good Health and Well Being copepods population dynamics mortality estimation density dependence life history trade-offs Calanus Pseudocalanus article 2002 ftcdlib 2023-06-05T18:03:09Z We present the first comparative study of the stage-specific patterns of mortality of Calanus and Pseudocalanus, two widely distributed genera that are representative of a relatively large-bodied, broadcast spawning calanoid copepod and a relatively small-bodied, egg-brooding calanoid. The study site is Georges Bank, a continental shelf locality in the Northwestern Atlantic with retentive circulation that renders it suitable for studies of population dynamics. Based on extensive mortality estimates from 30 cruises, we find that co-occurring Calanus finmarchicus and Pseudocalanus spp. have markedly different patterns of stage-specific mortality, the former bimodal and the latter relatively uniform with respect to developmental stage. Neither taxon exhibits a monotonic decline in mortality with developmental stage, nor are rates of mortality predictable in a useful manner by copepod body size or by ambient temperature. Young stages of the broadcast-spawning C. finmarchicus show conditional density-dependence of mortality rates, i.e. mortality rates are independent of population density when adult females are low in abundance but positively related to population density at high female abundances. This density-dependence, which is probably attributable to egg cannibalism, introduces a quadratic mortality term into population dynamic models. The egg-brooding Pseudocalanus spp., in contrast, show no evidence of density-dependent mortality. The two taxa illustrate a life history trade-off: the broadcast-spawning Calanus exhibits birth rates that are greatly elevated with respect to those of Pseudocalanus, but there is a compensatory cost in very low survivorship of the freely spawned eggs. Both the high fecundity, high mortality life history of Calanus and the low fecundity, low mortality life history of Pseudocalanus appear to have approximately equal fitness in this study site. Article in Journal/Newspaper Calanus finmarchicus Copepods University of California: eScholarship |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Good Health and Well Being copepods population dynamics mortality estimation density dependence life history trade-offs Calanus Pseudocalanus |
spellingShingle |
Good Health and Well Being copepods population dynamics mortality estimation density dependence life history trade-offs Calanus Pseudocalanus Ohman, Mark D Runge, Jeffrey A Durbin, Edward G Field, David B Niehoff, Barbara On birth and death in the sea |
topic_facet |
Good Health and Well Being copepods population dynamics mortality estimation density dependence life history trade-offs Calanus Pseudocalanus |
description |
We present the first comparative study of the stage-specific patterns of mortality of Calanus and Pseudocalanus, two widely distributed genera that are representative of a relatively large-bodied, broadcast spawning calanoid copepod and a relatively small-bodied, egg-brooding calanoid. The study site is Georges Bank, a continental shelf locality in the Northwestern Atlantic with retentive circulation that renders it suitable for studies of population dynamics. Based on extensive mortality estimates from 30 cruises, we find that co-occurring Calanus finmarchicus and Pseudocalanus spp. have markedly different patterns of stage-specific mortality, the former bimodal and the latter relatively uniform with respect to developmental stage. Neither taxon exhibits a monotonic decline in mortality with developmental stage, nor are rates of mortality predictable in a useful manner by copepod body size or by ambient temperature. Young stages of the broadcast-spawning C. finmarchicus show conditional density-dependence of mortality rates, i.e. mortality rates are independent of population density when adult females are low in abundance but positively related to population density at high female abundances. This density-dependence, which is probably attributable to egg cannibalism, introduces a quadratic mortality term into population dynamic models. The egg-brooding Pseudocalanus spp., in contrast, show no evidence of density-dependent mortality. The two taxa illustrate a life history trade-off: the broadcast-spawning Calanus exhibits birth rates that are greatly elevated with respect to those of Pseudocalanus, but there is a compensatory cost in very low survivorship of the freely spawned eggs. Both the high fecundity, high mortality life history of Calanus and the low fecundity, low mortality life history of Pseudocalanus appear to have approximately equal fitness in this study site. |
format |
Article in Journal/Newspaper |
author |
Ohman, Mark D Runge, Jeffrey A Durbin, Edward G Field, David B Niehoff, Barbara |
author_facet |
Ohman, Mark D Runge, Jeffrey A Durbin, Edward G Field, David B Niehoff, Barbara |
author_sort |
Ohman, Mark D |
title |
On birth and death in the sea |
title_short |
On birth and death in the sea |
title_full |
On birth and death in the sea |
title_fullStr |
On birth and death in the sea |
title_full_unstemmed |
On birth and death in the sea |
title_sort |
on birth and death in the sea |
publisher |
eScholarship, University of California |
publishDate |
2002 |
url |
https://escholarship.org/uc/item/4f52v6ds |
op_coverage |
55 - 68 |
genre |
Calanus finmarchicus Copepods |
genre_facet |
Calanus finmarchicus Copepods |
op_source |
Hydrobiologia, vol 480, iss 1-3 |
op_relation |
qt4f52v6ds https://escholarship.org/uc/item/4f52v6ds |
op_rights |
public |
_version_ |
1769004882943016960 |