Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion
To quantify the influence of common eiders (Somateria mollissima) on their food supply in the Gulf of St. Lawrence, eastern Canada, we measured prey availability and patch utilization during two consecutive winters. In this region, eiders fed predominantly near submerged reefs where large population...
Published in: | Canadian Journal of Zoology |
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Language: | English |
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Canadian Science Publishing
1996
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Online Access: | http://dx.doi.org/10.1139/z96-005 http://www.nrcresearchpress.com/doi/pdf/10.1139/z96-005 |
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crcansciencepubl:10.1139/z96-005 2024-09-15T18:36:01+00:00 Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion Gulllemette, Magella Himmelman, John H. Reed, Austin 1996 http://dx.doi.org/10.1139/z96-005 http://www.nrcresearchpress.com/doi/pdf/10.1139/z96-005 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 74, issue 1, page 32-38 ISSN 0008-4301 1480-3283 journal-article 1996 crcansciencepubl https://doi.org/10.1139/z96-005 2024-07-04T04:10:00Z To quantify the influence of common eiders (Somateria mollissima) on their food supply in the Gulf of St. Lawrence, eastern Canada, we measured prey availability and patch utilization during two consecutive winters. In this region, eiders fed predominantly near submerged reefs where large populations of blue mussels (Mytilus edulis) and green sea urchins (Strongylocentrotus droebachienensis) were present. Density and biomass of mussels and urchins were estimated for two reefs at the beginning of the winter of 1985 – 1986 using SCUBA and quadrat sampling. Prey selection was assessed by comparing the size of prey from stomach contents of shot eiders with that of prey found in the habitat. Patch use was quantified from elevated blinds by regularly counting eiders from December to April. Mussels in the habitat were small (mean length 6.5 mm) and formed dense beds (mean density 25 398 individuals/m 2 ), whereas urchins were large (mean diameter 35 mm) and occurred at lower densities (114 individuals/m 2 ). However, the average biomass for these two prey species was similar, 2.8 and 3.1 kg wet mass/m 2 for mussels and urchins, respectively. The mussels eaten by common eiders tended to be larger than the average size of those available. In contrast, urchins eaten were smaller than the average size present in the habitat. Depending on the reef, consumption of food by eiders ranged from 48 to 69% of the biomass for eiders feeding on mussels and from 3 to 6% of the biomass for urchins. We compared these estimates with those from similar studies and concluded that eiders substantially deplete mussel beds in winter, which in turn seems to affect their distribution. Article in Journal/Newspaper Somateria mollissima Canadian Science Publishing Canadian Journal of Zoology 74 1 32 38 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
To quantify the influence of common eiders (Somateria mollissima) on their food supply in the Gulf of St. Lawrence, eastern Canada, we measured prey availability and patch utilization during two consecutive winters. In this region, eiders fed predominantly near submerged reefs where large populations of blue mussels (Mytilus edulis) and green sea urchins (Strongylocentrotus droebachienensis) were present. Density and biomass of mussels and urchins were estimated for two reefs at the beginning of the winter of 1985 – 1986 using SCUBA and quadrat sampling. Prey selection was assessed by comparing the size of prey from stomach contents of shot eiders with that of prey found in the habitat. Patch use was quantified from elevated blinds by regularly counting eiders from December to April. Mussels in the habitat were small (mean length 6.5 mm) and formed dense beds (mean density 25 398 individuals/m 2 ), whereas urchins were large (mean diameter 35 mm) and occurred at lower densities (114 individuals/m 2 ). However, the average biomass for these two prey species was similar, 2.8 and 3.1 kg wet mass/m 2 for mussels and urchins, respectively. The mussels eaten by common eiders tended to be larger than the average size of those available. In contrast, urchins eaten were smaller than the average size present in the habitat. Depending on the reef, consumption of food by eiders ranged from 48 to 69% of the biomass for eiders feeding on mussels and from 3 to 6% of the biomass for urchins. We compared these estimates with those from similar studies and concluded that eiders substantially deplete mussel beds in winter, which in turn seems to affect their distribution. |
format |
Article in Journal/Newspaper |
author |
Gulllemette, Magella Himmelman, John H. Reed, Austin |
spellingShingle |
Gulllemette, Magella Himmelman, John H. Reed, Austin Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion |
author_facet |
Gulllemette, Magella Himmelman, John H. Reed, Austin |
author_sort |
Gulllemette, Magella |
title |
Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion |
title_short |
Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion |
title_full |
Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion |
title_fullStr |
Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion |
title_full_unstemmed |
Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion |
title_sort |
availability and consumption of food by common eiders wintering in the gulf of st. lawrence: evidence of prey depletion |
publisher |
Canadian Science Publishing |
publishDate |
1996 |
url |
http://dx.doi.org/10.1139/z96-005 http://www.nrcresearchpress.com/doi/pdf/10.1139/z96-005 |
genre |
Somateria mollissima |
genre_facet |
Somateria mollissima |
op_source |
Canadian Journal of Zoology volume 74, issue 1, page 32-38 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z96-005 |
container_title |
Canadian Journal of Zoology |
container_volume |
74 |
container_issue |
1 |
container_start_page |
32 |
op_container_end_page |
38 |
_version_ |
1810479201833189376 |