Does Estuary Prey Abundance and Diversity Buffer Salmo salar (Atlantic Salmon) Smolts from Predation by Nannopterum auritum (Double-Crested Cormorant)?
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| Title: | Does Estuary Prey Abundance and Diversity Buffer Salmo salar (Atlantic Salmon) Smolts from Predation by Nannopterum auritum (Double-Crested Cormorant)? |
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| Authors: | Frechette, Danielle1,2 (AUTHOR) danielle.frechette@maine.gov, Carrier, Joanie2 (AUTHOR), Leblanc, David3 (AUTHOR), Carr, Jonathan4 (AUTHOR), Bergeron, Normand2,5 (AUTHOR), Vicaire, John Murvin2,3,6 (AUTHOR), Gillis, Carole-Anne6 (AUTHOR) |
| Source: | Northeastern Naturalist. 2026, Vol. 33 Issue 2, p295-321. 27p. |
| Subjects: | Prey availability, Cormorants, Estuary management, Biodiversity, Predation, Forage fishes, Atlantic salmon, Wildlife management |
| Geographic Terms: | Gulf of Saint Lawrence |
| Abstract: | Substantial decreases in fish stocks have been attributed in part to seabird predation. In many parts of the world, cormorant populations have been increasing since the end of the 1970s, as colonies recover from the effects of human exploitation and impacts of environmental contaminants. In coastal regions of the Gulf of St. Lawrence, Nannopterum auritum (Double-crested Cormorant, hereinafter "Cormorant") are now abundant. To reach the ocean, Salmo salar (Atlantic Salmon) smolts originating from the Restigouche River watershed must migrate past a colony of breeding Cormorants located at the mouth of the river on Wisugunetg (Bon Ami Rocks). Cormorants were absent from this rocky islet as late as the end of the 20th century. We estimated the number of breeding pairs and assessed diet composition of Cormorants using this colony during the smolt-emigration period to assess the predation risk posed to Restigouche River smolts by Cormorants. We counted Cormorant nests from aerial-imaging surveys via fixed wing aircraft and a drone (2013–2015). We identified and enumerated prey items using otoliths extracted from Cormorant pellets collected during smolt emigration in 2014 and 2015. The Wisugunetg colony increased from 554 pairs in 2013 to 1147 pairs in 2015. We identified only 3 Atlantic Salmon smolts from 874 sampled pellets. The most prevalent prey species were Osmerus mordax (Rainbow Smelt), Lumpenus lampretaeformis (Snakeblenny), Microgadus tomcod (Atlantic Tomcod), and Pseudopleuronectes americanus (Winter Flounder). Cormorant diet reflected seasonality in prey abundance, with Rainbow Smelt dominating diet in May, and Winter Flounder becoming more dominant in June. These results indicate that Restigouche smolts contribute minimally to the diet of Cormorants nesting at Wisugunetg. Rather, the abundance of diverse, alternative prey near the breeding colony appears to provide a buffer that protects Atlantic Salmon smolts from predation by Cormorants. This natural buffer highlights the role of biodiversity in predator–prey relationships and underscores the importance of multi-species management strategies in effective stewardship. [ABSTRACT FROM AUTHOR] |
| Copyright of Northeastern Naturalist is the property of Eagle Hill Institute and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
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| Header | DbId: egs DbLabel: Engineering Source An: 195221527 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Does Estuary Prey Abundance and Diversity Buffer Salmo salar (Atlantic Salmon) Smolts from Predation by Nannopterum auritum (Double-Crested Cormorant)? – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Frechette%2C+Danielle%22">Frechette, Danielle</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> danielle.frechette@maine.gov</i><br /><searchLink fieldCode="AR" term="%22Carrier%2C+Joanie%22">Carrier, Joanie</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Leblanc%2C+David%22">Leblanc, David</searchLink><relatesTo>3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Carr%2C+Jonathan%22">Carr, Jonathan</searchLink><relatesTo>4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Bergeron%2C+Normand%22">Bergeron, Normand</searchLink><relatesTo>2,5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Vicaire%2C+John+Murvin%22">Vicaire, John Murvin</searchLink><relatesTo>2,3,6</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Gillis%2C+Carole-Anne%22">Gillis, Carole-Anne</searchLink><relatesTo>6</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Northeastern+Naturalist%22">Northeastern Naturalist</searchLink>. 2026, Vol. 33 Issue 2, p295-321. 27p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Prey+availability%22">Prey availability</searchLink><br /><searchLink fieldCode="DE" term="%22Cormorants%22">Cormorants</searchLink><br /><searchLink fieldCode="DE" term="%22Estuary+management%22">Estuary management</searchLink><br /><searchLink fieldCode="DE" term="%22Biodiversity%22">Biodiversity</searchLink><br /><searchLink fieldCode="DE" term="%22Predation%22">Predation</searchLink><br /><searchLink fieldCode="DE" term="%22Forage+fishes%22">Forage fishes</searchLink><br /><searchLink fieldCode="DE" term="%22Atlantic+salmon%22">Atlantic salmon</searchLink><br /><searchLink fieldCode="DE" term="%22Wildlife+management%22">Wildlife management</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22Gulf+of+Saint+Lawrence%22">Gulf of Saint Lawrence</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Substantial decreases in fish stocks have been attributed in part to seabird predation. In many parts of the world, cormorant populations have been increasing since the end of the 1970s, as colonies recover from the effects of human exploitation and impacts of environmental contaminants. In coastal regions of the Gulf of St. Lawrence, Nannopterum auritum (Double-crested Cormorant, hereinafter "Cormorant") are now abundant. To reach the ocean, Salmo salar (Atlantic Salmon) smolts originating from the Restigouche River watershed must migrate past a colony of breeding Cormorants located at the mouth of the river on Wisugunetg (Bon Ami Rocks). Cormorants were absent from this rocky islet as late as the end of the 20th century. We estimated the number of breeding pairs and assessed diet composition of Cormorants using this colony during the smolt-emigration period to assess the predation risk posed to Restigouche River smolts by Cormorants. We counted Cormorant nests from aerial-imaging surveys via fixed wing aircraft and a drone (2013–2015). We identified and enumerated prey items using otoliths extracted from Cormorant pellets collected during smolt emigration in 2014 and 2015. The Wisugunetg colony increased from 554 pairs in 2013 to 1147 pairs in 2015. We identified only 3 Atlantic Salmon smolts from 874 sampled pellets. The most prevalent prey species were Osmerus mordax (Rainbow Smelt), Lumpenus lampretaeformis (Snakeblenny), Microgadus tomcod (Atlantic Tomcod), and Pseudopleuronectes americanus (Winter Flounder). Cormorant diet reflected seasonality in prey abundance, with Rainbow Smelt dominating diet in May, and Winter Flounder becoming more dominant in June. These results indicate that Restigouche smolts contribute minimally to the diet of Cormorants nesting at Wisugunetg. Rather, the abundance of diverse, alternative prey near the breeding colony appears to provide a buffer that protects Atlantic Salmon smolts from predation by Cormorants. This natural buffer highlights the role of biodiversity in predator–prey relationships and underscores the importance of multi-species management strategies in effective stewardship. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Northeastern Naturalist is the property of Eagle Hill Institute and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1656/045.033.0215 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 27 StartPage: 295 Subjects: – SubjectFull: Prey availability Type: general – SubjectFull: Cormorants Type: general – SubjectFull: Estuary management Type: general – SubjectFull: Biodiversity Type: general – SubjectFull: Predation Type: general – SubjectFull: Forage fishes Type: general – SubjectFull: Atlantic salmon Type: general – SubjectFull: Wildlife management Type: general – SubjectFull: Gulf of Saint Lawrence Type: general Titles: – TitleFull: Does Estuary Prey Abundance and Diversity Buffer Salmo salar (Atlantic Salmon) Smolts from Predation by Nannopterum auritum (Double-Crested Cormorant)? Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Frechette, Danielle – PersonEntity: Name: NameFull: Carrier, Joanie – PersonEntity: Name: NameFull: Leblanc, David – PersonEntity: Name: NameFull: Carr, Jonathan – PersonEntity: Name: NameFull: Bergeron, Normand – PersonEntity: Name: NameFull: Vicaire, John Murvin – PersonEntity: Name: NameFull: Gillis, Carole-Anne IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 06 Text: 2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 10926194 Numbering: – Type: volume Value: 33 – Type: issue Value: 2 Titles: – TitleFull: Northeastern Naturalist Type: main |
| ResultId | 1 |
