THE DETERMINANTS OF PRODUCTION IN NORTHERN SEAS: A STUDY OF THE BIOLOGY OF THEMISTO LIBELLULA MANDT.
The level of production in the sea is determined not only by the extrinsic factors of the environment, but also by the intrinsic response of the organism to those factors, temperature in particular. In cold seas, the degree of adaptation to low temperature as regards activity, metabolism, growth rat...
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Canadian Science Publishing
1957
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crcansciencepubl:10.1139/z57-067 2024-09-30T14:31:34+00:00 THE DETERMINANTS OF PRODUCTION IN NORTHERN SEAS: A STUDY OF THE BIOLOGY OF THEMISTO LIBELLULA MANDT. Dunbar, M. J. 1957 http://dx.doi.org/10.1139/z57-067 http://www.nrcresearchpress.com/doi/pdf/10.1139/z57-067 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 35, issue 6, page 797-819 ISSN 0008-4301 1480-3283 journal-article 1957 crcansciencepubl https://doi.org/10.1139/z57-067 2024-09-05T04:11:16Z The level of production in the sea is determined not only by the extrinsic factors of the environment, but also by the intrinsic response of the organism to those factors, temperature in particular. In cold seas, the degree of adaptation to low temperature as regards activity, metabolism, growth rate, and the onset of maturity is therefore of great importance. This matter is reviewed and discussed here, and illustrated by a study of the growth rate, breeding cycle, and longevity of a dominant arctic pelagic amphipod, Themisto libellula Mandt.Themisto libellula, in Hudson Bay, Hudson Strait, and the waters of southeast Baffin Island, is shown to have a normal length of life of 2 years, although a 1-year or 15-month life cycle is a possibility in a small proportion of the population. Material from the months of November and December is lacking, but it appears that spawning extends from September through the winter until some time in May or June. If a temperature stimulus is involved in the onset of breeding, it appears to be a fall below, not a rise above, a critical point, since the temperatures during most of the breeding period are below −1.5 °C. The spawning in the autumn, however, suggests that temperature is in fact not involved.The alternating, or two-phase, breeding cycle is confirmed in this species, but the evidence shows that dislocations in the cycle (owing to the possibility of maturation after approximately one year in some individuals) may destroy the supposed reproductive isolation between adjacent year-classes. Article in Journal/Newspaper Arctic Baffin Island Baffin Hudson Bay Hudson Strait Themisto Themisto libellula Canadian Science Publishing Arctic Baffin Island Hudson Hudson Bay Hudson Strait ENVELOPE(-70.000,-70.000,62.000,62.000) Canadian Journal of Zoology 35 6 797 819 |
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Open Polar |
collection |
Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
The level of production in the sea is determined not only by the extrinsic factors of the environment, but also by the intrinsic response of the organism to those factors, temperature in particular. In cold seas, the degree of adaptation to low temperature as regards activity, metabolism, growth rate, and the onset of maturity is therefore of great importance. This matter is reviewed and discussed here, and illustrated by a study of the growth rate, breeding cycle, and longevity of a dominant arctic pelagic amphipod, Themisto libellula Mandt.Themisto libellula, in Hudson Bay, Hudson Strait, and the waters of southeast Baffin Island, is shown to have a normal length of life of 2 years, although a 1-year or 15-month life cycle is a possibility in a small proportion of the population. Material from the months of November and December is lacking, but it appears that spawning extends from September through the winter until some time in May or June. If a temperature stimulus is involved in the onset of breeding, it appears to be a fall below, not a rise above, a critical point, since the temperatures during most of the breeding period are below −1.5 °C. The spawning in the autumn, however, suggests that temperature is in fact not involved.The alternating, or two-phase, breeding cycle is confirmed in this species, but the evidence shows that dislocations in the cycle (owing to the possibility of maturation after approximately one year in some individuals) may destroy the supposed reproductive isolation between adjacent year-classes. |
format |
Article in Journal/Newspaper |
author |
Dunbar, M. J. |
spellingShingle |
Dunbar, M. J. THE DETERMINANTS OF PRODUCTION IN NORTHERN SEAS: A STUDY OF THE BIOLOGY OF THEMISTO LIBELLULA MANDT. |
author_facet |
Dunbar, M. J. |
author_sort |
Dunbar, M. J. |
title |
THE DETERMINANTS OF PRODUCTION IN NORTHERN SEAS: A STUDY OF THE BIOLOGY OF THEMISTO LIBELLULA MANDT. |
title_short |
THE DETERMINANTS OF PRODUCTION IN NORTHERN SEAS: A STUDY OF THE BIOLOGY OF THEMISTO LIBELLULA MANDT. |
title_full |
THE DETERMINANTS OF PRODUCTION IN NORTHERN SEAS: A STUDY OF THE BIOLOGY OF THEMISTO LIBELLULA MANDT. |
title_fullStr |
THE DETERMINANTS OF PRODUCTION IN NORTHERN SEAS: A STUDY OF THE BIOLOGY OF THEMISTO LIBELLULA MANDT. |
title_full_unstemmed |
THE DETERMINANTS OF PRODUCTION IN NORTHERN SEAS: A STUDY OF THE BIOLOGY OF THEMISTO LIBELLULA MANDT. |
title_sort |
determinants of production in northern seas: a study of the biology of themisto libellula mandt. |
publisher |
Canadian Science Publishing |
publishDate |
1957 |
url |
http://dx.doi.org/10.1139/z57-067 http://www.nrcresearchpress.com/doi/pdf/10.1139/z57-067 |
long_lat |
ENVELOPE(-70.000,-70.000,62.000,62.000) |
geographic |
Arctic Baffin Island Hudson Hudson Bay Hudson Strait |
geographic_facet |
Arctic Baffin Island Hudson Hudson Bay Hudson Strait |
genre |
Arctic Baffin Island Baffin Hudson Bay Hudson Strait Themisto Themisto libellula |
genre_facet |
Arctic Baffin Island Baffin Hudson Bay Hudson Strait Themisto Themisto libellula |
op_source |
Canadian Journal of Zoology volume 35, issue 6, page 797-819 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z57-067 |
container_title |
Canadian Journal of Zoology |
container_volume |
35 |
container_issue |
6 |
container_start_page |
797 |
op_container_end_page |
819 |
_version_ |
1811636044631638016 |