Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis
Abstract Capelin (Mallotus villosus) is the key forage fish species in the Newfoundland and Labrador Shelf ecosystem. Capelin stocks collapsed in the early 1990s, concurrent with declines in “northern” Atlantic cod, Gadus morhua. Neither has fully recovered yet. Changes in growth, condition, and beh...
Published in: | ICES Journal of Marine Science |
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Language: | English |
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Oxford University Press (OUP)
2013
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Online Access: | http://dx.doi.org/10.1093/icesjms/fst184 http://academic.oup.com/icesjms/article-pdf/71/4/775/29146568/fst184.pdf |
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croxfordunivpr:10.1093/icesjms/fst184 2024-09-15T17:55:33+00:00 Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis Obradovich, Shannon G. Carruthers, Erin H. Rose, George A. 2013 http://dx.doi.org/10.1093/icesjms/fst184 http://academic.oup.com/icesjms/article-pdf/71/4/775/29146568/fst184.pdf en eng Oxford University Press (OUP) http://creativecommons.org/licenses/by/3.0/ ICES Journal of Marine Science volume 71, issue 4, page 775-783 ISSN 1095-9289 1054-3139 journal-article 2013 croxfordunivpr https://doi.org/10.1093/icesjms/fst184 2024-08-05T04:30:54Z Abstract Capelin (Mallotus villosus) is the key forage fish species in the Newfoundland and Labrador Shelf ecosystem. Capelin stocks collapsed in the early 1990s, concurrent with declines in “northern” Atlantic cod, Gadus morhua. Neither has fully recovered yet. Changes in growth, condition, and behaviour accompanied capelin declines on the northern Grand Banks (NGB), and remain two decades later. Feeding, growth, and condition of NGB capelin were all lower when compared with capelin from the eastern Scotian Shelf (ESS), where abundance increased following predator declines. For age 2–5 capelin of both sexes, all but one of five comparable age–sex groups were significantly larger on the ESS (e.g. age 3 females average 169 mm on the ESS and 151 mm on the NGB). Neither temperature nor density-dependence explain these differences. However, dietary differences were prominent. ESS capelin had higher total fullness indices (TFIs) than NGB fish at all sizes [mean TFIESS = 1.43 (± 1.14), mean TFINGB = 0.48 (± 0.70)]. Euphausiids (especially Thysanoessa spp.) were a main dietary component on the ESS but not on the NGB. Stable isotope analyses (δ15N and δ13C) for NGB capelin also indicated few dietary euphausiids. Trophic fractionation of δ 15N was 4.740/00, suggesting NGB capelin were food limited. Capelin recovery on the Newfoundland and Labrador Shelf appears limited by bottom-up forcing, in particular lack of euphausiid prey. Article in Journal/Newspaper atlantic cod Gadus morhua Newfoundland Oxford University Press ICES Journal of Marine Science 71 4 775 783 |
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Open Polar |
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Oxford University Press |
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croxfordunivpr |
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English |
description |
Abstract Capelin (Mallotus villosus) is the key forage fish species in the Newfoundland and Labrador Shelf ecosystem. Capelin stocks collapsed in the early 1990s, concurrent with declines in “northern” Atlantic cod, Gadus morhua. Neither has fully recovered yet. Changes in growth, condition, and behaviour accompanied capelin declines on the northern Grand Banks (NGB), and remain two decades later. Feeding, growth, and condition of NGB capelin were all lower when compared with capelin from the eastern Scotian Shelf (ESS), where abundance increased following predator declines. For age 2–5 capelin of both sexes, all but one of five comparable age–sex groups were significantly larger on the ESS (e.g. age 3 females average 169 mm on the ESS and 151 mm on the NGB). Neither temperature nor density-dependence explain these differences. However, dietary differences were prominent. ESS capelin had higher total fullness indices (TFIs) than NGB fish at all sizes [mean TFIESS = 1.43 (± 1.14), mean TFINGB = 0.48 (± 0.70)]. Euphausiids (especially Thysanoessa spp.) were a main dietary component on the ESS but not on the NGB. Stable isotope analyses (δ15N and δ13C) for NGB capelin also indicated few dietary euphausiids. Trophic fractionation of δ 15N was 4.740/00, suggesting NGB capelin were food limited. Capelin recovery on the Newfoundland and Labrador Shelf appears limited by bottom-up forcing, in particular lack of euphausiid prey. |
format |
Article in Journal/Newspaper |
author |
Obradovich, Shannon G. Carruthers, Erin H. Rose, George A. |
spellingShingle |
Obradovich, Shannon G. Carruthers, Erin H. Rose, George A. Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis |
author_facet |
Obradovich, Shannon G. Carruthers, Erin H. Rose, George A. |
author_sort |
Obradovich, Shannon G. |
title |
Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis |
title_short |
Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis |
title_full |
Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis |
title_fullStr |
Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis |
title_full_unstemmed |
Bottom-up limits to Newfoundland capelin (Mallotus villosus) rebuilding: the euphausiid hypothesis |
title_sort |
bottom-up limits to newfoundland capelin (mallotus villosus) rebuilding: the euphausiid hypothesis |
publisher |
Oxford University Press (OUP) |
publishDate |
2013 |
url |
http://dx.doi.org/10.1093/icesjms/fst184 http://academic.oup.com/icesjms/article-pdf/71/4/775/29146568/fst184.pdf |
genre |
atlantic cod Gadus morhua Newfoundland |
genre_facet |
atlantic cod Gadus morhua Newfoundland |
op_source |
ICES Journal of Marine Science volume 71, issue 4, page 775-783 ISSN 1095-9289 1054-3139 |
op_rights |
http://creativecommons.org/licenses/by/3.0/ |
op_doi |
https://doi.org/10.1093/icesjms/fst184 |
container_title |
ICES Journal of Marine Science |
container_volume |
71 |
container_issue |
4 |
container_start_page |
775 |
op_container_end_page |
783 |
_version_ |
1810431820137758720 |