Variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal Newfoundland, Canada
Abstract Forage fish species provide essential linkages for energy transfer within pelagic marine food webs. Capelin (Mallotus villosus), the focal forage fish in coastal Newfoundland, Canada, suffered a stock collapse in 1991 and has not recovered. Despite this collapse, capelin continue to provide...
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Oxford University Press (OUP)
2024
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Online Access: | http://dx.doi.org/10.1093/icesjms/fsae021 https://academic.oup.com/icesjms/article-pdf/81/4/629/57945816/fsae021.pdf |
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croxfordunivpr:10.1093/icesjms/fsae021 2024-06-23T07:54:43+00:00 Variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal Newfoundland, Canada Davoren, Gail K Browman, Howard Natural Sciences and Engineering Research Council of Canada 2024 http://dx.doi.org/10.1093/icesjms/fsae021 https://academic.oup.com/icesjms/article-pdf/81/4/629/57945816/fsae021.pdf en eng Oxford University Press (OUP) https://creativecommons.org/licenses/by/4.0/ ICES Journal of Marine Science volume 81, issue 4, page 629-642 ISSN 1054-3139 1095-9289 journal-article 2024 croxfordunivpr https://doi.org/10.1093/icesjms/fsae021 2024-06-04T06:10:51Z Abstract Forage fish species provide essential linkages for energy transfer within pelagic marine food webs. Capelin (Mallotus villosus), the focal forage fish in coastal Newfoundland, Canada, suffered a stock collapse in 1991 and has not recovered. Despite this collapse, capelin continue to provide locally abundant prey aggregations. Here, I synthesize the lessons learned from a long-term capelin-predator research program (2004–2022) on the northeast Newfoundland coast during the postcollapse period. I highlight the importance of simultaneously estimating forage fish biomass and predator responses in a multispecies and multiyear context. High interannual variation in capelin spawning timing and biomass was observed. Lower capelin biomass consistently resulted in predator species- and assemblage-level dietary shifts toward a higher diversity of lower trophic level, alternative prey. Energetic foraging costs of seabirds also increased under lower capelin biomass, but responses differed among species. Summer capelin consumption by dominant seabirds (9389 tonnes) and whales (778 tonnes) indicated predator energetic requirements and revealed higher natural mortality relative to fishery-based (1289 tonnes) mortality. Overall, this case study illustrated that, despite high observed behavioural plasticity, varying species-specific predator responses to changing capelin biomass integrated to increase potential competitive interactions under low capelin biomass, providing a basis for ecosystem-level change. Article in Journal/Newspaper Newfoundland Oxford University Press Canada ICES Journal of Marine Science 81 4 629 642 |
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Oxford University Press |
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English |
description |
Abstract Forage fish species provide essential linkages for energy transfer within pelagic marine food webs. Capelin (Mallotus villosus), the focal forage fish in coastal Newfoundland, Canada, suffered a stock collapse in 1991 and has not recovered. Despite this collapse, capelin continue to provide locally abundant prey aggregations. Here, I synthesize the lessons learned from a long-term capelin-predator research program (2004–2022) on the northeast Newfoundland coast during the postcollapse period. I highlight the importance of simultaneously estimating forage fish biomass and predator responses in a multispecies and multiyear context. High interannual variation in capelin spawning timing and biomass was observed. Lower capelin biomass consistently resulted in predator species- and assemblage-level dietary shifts toward a higher diversity of lower trophic level, alternative prey. Energetic foraging costs of seabirds also increased under lower capelin biomass, but responses differed among species. Summer capelin consumption by dominant seabirds (9389 tonnes) and whales (778 tonnes) indicated predator energetic requirements and revealed higher natural mortality relative to fishery-based (1289 tonnes) mortality. Overall, this case study illustrated that, despite high observed behavioural plasticity, varying species-specific predator responses to changing capelin biomass integrated to increase potential competitive interactions under low capelin biomass, providing a basis for ecosystem-level change. |
author2 |
Browman, Howard Natural Sciences and Engineering Research Council of Canada |
format |
Article in Journal/Newspaper |
author |
Davoren, Gail K |
spellingShingle |
Davoren, Gail K Variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal Newfoundland, Canada |
author_facet |
Davoren, Gail K |
author_sort |
Davoren, Gail K |
title |
Variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal Newfoundland, Canada |
title_short |
Variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal Newfoundland, Canada |
title_full |
Variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal Newfoundland, Canada |
title_fullStr |
Variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal Newfoundland, Canada |
title_full_unstemmed |
Variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal Newfoundland, Canada |
title_sort |
variable forage fish biomass and phenology influence marine predator diet, foraging behavior, and species interactions in coastal newfoundland, canada |
publisher |
Oxford University Press (OUP) |
publishDate |
2024 |
url |
http://dx.doi.org/10.1093/icesjms/fsae021 https://academic.oup.com/icesjms/article-pdf/81/4/629/57945816/fsae021.pdf |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
ICES Journal of Marine Science volume 81, issue 4, page 629-642 ISSN 1054-3139 1095-9289 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1093/icesjms/fsae021 |
container_title |
ICES Journal of Marine Science |
container_volume |
81 |
container_issue |
4 |
container_start_page |
629 |
op_container_end_page |
642 |
_version_ |
1802646983440072704 |