Long-term trends in reproductive and demographic parameters of female Northwest Atlantic hooded seals ( Cystophora cristata ): population responses to ecosystem change?
More than 2500 ovaries were collected from Northwest Atlantic hooded seals ( Cystophora cristata (Erxleben, 1777)) in the period 1956–2006 during moulting (data blocks: 1956–1960, 1970–1972, 1978), postmoulting (data blocks: 1990–1994, 1996–2006), and whelping (data blocks: 1967–1972, 1973–1976, 197...
Published in: | Canadian Journal of Zoology |
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2012
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Online Access: | http://dx.doi.org/10.1139/z11-140 http://www.nrcresearchpress.com/doi/full-xml/10.1139/z11-140 http://www.nrcresearchpress.com/doi/pdf/10.1139/z11-140 |
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crcansciencepubl:10.1139/z11-140 2023-12-17T10:29:20+01:00 Long-term trends in reproductive and demographic parameters of female Northwest Atlantic hooded seals ( Cystophora cristata ): population responses to ecosystem change? Frie, Anne Kirstine Stenson, Garry B. Haug, Tore 2012 http://dx.doi.org/10.1139/z11-140 http://www.nrcresearchpress.com/doi/full-xml/10.1139/z11-140 http://www.nrcresearchpress.com/doi/pdf/10.1139/z11-140 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 90, issue 3, page 376-392 ISSN 0008-4301 1480-3283 Animal Science and Zoology Ecology, Evolution, Behavior and Systematics journal-article 2012 crcansciencepubl https://doi.org/10.1139/z11-140 2023-11-19T13:39:39Z More than 2500 ovaries were collected from Northwest Atlantic hooded seals ( Cystophora cristata (Erxleben, 1777)) in the period 1956–2006 during moulting (data blocks: 1956–1960, 1970–1972, 1978), postmoulting (data blocks: 1990–1994, 1996–2006), and whelping (data blocks: 1967–1972, 1973–1976, 1979, 1983–1987, 1989–1995). Mean age at primiparity (MAP) was estimated as the mean age of females with a single corpus albicans or a corpus luteum from a postimplantation pregnancy. MAP was stable at 4.2–4.5 years during 1956–1978, increasing to 4.9–5.2 years in 1979 and to 6.1 years in 1989–1995 (later data insufficient). Patterns of corpus accumulation indicated occasional skipped pregnancies. This may have affected the accuracy of MAP estimates but not the main trends. Declining proportions of parae younger than 10 years after 1979 are consistent with effects of delayed maturation, reduced adult hunting mortality, and (or) increased juvenile mortality. From the 1990s, declining adult pregnancy rates are suggested by decreasing trends in proportions of older multiparae (8+) and other ovary-based proxies for pregnancy rates. Hooded seal abundance was largely stable from 1960 to the mid-1990s and changes in population parameters over this period are therefore more likely due to effects of ecosystem change on per-capita resource levels than population-mediated density dependence. Article in Journal/Newspaper Cystophora cristata hooded seal Northwest Atlantic Canadian Science Publishing (via Crossref) Canadian Journal of Zoology 90 3 376 392 |
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Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics Frie, Anne Kirstine Stenson, Garry B. Haug, Tore Long-term trends in reproductive and demographic parameters of female Northwest Atlantic hooded seals ( Cystophora cristata ): population responses to ecosystem change? |
topic_facet |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
description |
More than 2500 ovaries were collected from Northwest Atlantic hooded seals ( Cystophora cristata (Erxleben, 1777)) in the period 1956–2006 during moulting (data blocks: 1956–1960, 1970–1972, 1978), postmoulting (data blocks: 1990–1994, 1996–2006), and whelping (data blocks: 1967–1972, 1973–1976, 1979, 1983–1987, 1989–1995). Mean age at primiparity (MAP) was estimated as the mean age of females with a single corpus albicans or a corpus luteum from a postimplantation pregnancy. MAP was stable at 4.2–4.5 years during 1956–1978, increasing to 4.9–5.2 years in 1979 and to 6.1 years in 1989–1995 (later data insufficient). Patterns of corpus accumulation indicated occasional skipped pregnancies. This may have affected the accuracy of MAP estimates but not the main trends. Declining proportions of parae younger than 10 years after 1979 are consistent with effects of delayed maturation, reduced adult hunting mortality, and (or) increased juvenile mortality. From the 1990s, declining adult pregnancy rates are suggested by decreasing trends in proportions of older multiparae (8+) and other ovary-based proxies for pregnancy rates. Hooded seal abundance was largely stable from 1960 to the mid-1990s and changes in population parameters over this period are therefore more likely due to effects of ecosystem change on per-capita resource levels than population-mediated density dependence. |
format |
Article in Journal/Newspaper |
author |
Frie, Anne Kirstine Stenson, Garry B. Haug, Tore |
author_facet |
Frie, Anne Kirstine Stenson, Garry B. Haug, Tore |
author_sort |
Frie, Anne Kirstine |
title |
Long-term trends in reproductive and demographic parameters of female Northwest Atlantic hooded seals ( Cystophora cristata ): population responses to ecosystem change? |
title_short |
Long-term trends in reproductive and demographic parameters of female Northwest Atlantic hooded seals ( Cystophora cristata ): population responses to ecosystem change? |
title_full |
Long-term trends in reproductive and demographic parameters of female Northwest Atlantic hooded seals ( Cystophora cristata ): population responses to ecosystem change? |
title_fullStr |
Long-term trends in reproductive and demographic parameters of female Northwest Atlantic hooded seals ( Cystophora cristata ): population responses to ecosystem change? |
title_full_unstemmed |
Long-term trends in reproductive and demographic parameters of female Northwest Atlantic hooded seals ( Cystophora cristata ): population responses to ecosystem change? |
title_sort |
long-term trends in reproductive and demographic parameters of female northwest atlantic hooded seals ( cystophora cristata ): population responses to ecosystem change? |
publisher |
Canadian Science Publishing |
publishDate |
2012 |
url |
http://dx.doi.org/10.1139/z11-140 http://www.nrcresearchpress.com/doi/full-xml/10.1139/z11-140 http://www.nrcresearchpress.com/doi/pdf/10.1139/z11-140 |
genre |
Cystophora cristata hooded seal Northwest Atlantic |
genre_facet |
Cystophora cristata hooded seal Northwest Atlantic |
op_source |
Canadian Journal of Zoology volume 90, issue 3, page 376-392 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z11-140 |
container_title |
Canadian Journal of Zoology |
container_volume |
90 |
container_issue |
3 |
container_start_page |
376 |
op_container_end_page |
392 |
_version_ |
1785581686165078016 |