Food Habits of Flightless American Eiders (<i>Somateria mollissima dresseri</i>) in Québec, Canada

Houle, Kenny; English, Matthew D.; Savard, Jean‐Pierre L.; Giroux, Jean‐François; Craik, Shawn R.

doi:10.1656/045.024.0206

Cited by 2 publications

(2 citation statements)

References 19 publications

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“…Bivalves, especially mussels, are principal prey for several sea duck species in cluding eiders Somateria spp. (Bustnes & Erikstad 1988, Houle et al 2017. Eiders dive to feed on a variety of benthic invertebrates (Ydenberg & Guille mette 1991) and although they can dive down to 50 m, they generally prefer shallower waters (0 to 10 m) where benthic prey are most abundant (Guille mette et al 1993) and accessible.…”

Section: Introductionmentioning

confidence: 99%

Predicting eider predation potentials on mussels in Danish coastal areas—implications for mussel farming site-selection

Tjørnløv

Holbach

Timmermann

2023

Aquacult. Environ. Interact.

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Selecting optimal locations for mussel farming is vital for the optimization of production yield and for the minimization of environmental impact. Although predation by sea ducks may induce large stock losses and hence severe economic loss for mussel farmers, predation potential is rarely included in site-selection tools. In this paper we present a GIS-based spatial model predicting the potential of eider predation on blue mussel farms in Danish coastal waters. The model incorporates national survey data on eiders, as well as knowledge of eider behavior and habitat preferences, and was calibrated with predated/non-predated observations of eiders from 9 experimental mussel farms or test lines in Danish coastal waters. Except for 1 case study area, our model successfully confirmed a higher predation potential at test sites where predation had been observed. Our resulting predation potential map revealed potentials ranging from very low in inner parts of narrow estuaries to very high in more open coastal areas. Integration of the predation map into an existing site-selection tool showed that areas optimal for mussel growth were also associated with the highest modelled predation potential. Nonetheless, it was possible to identify areas having a very low potential of predation and only a 10% lower mussel production potential. These results underpin the potential for reducing production loss and increasing income by including predation potential in site-selection tools. In addition, the eider predation model can be used to identify and subsequently protect key foraging areas to support eider conservation.

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Section: Introductionmentioning

confidence: 99%

Predicting eider predation potentials on mussels in Danish coastal areas—implications for mussel farming site-selection

Tjørnløv

Holbach

Timmermann

2023

Aquacult. Environ. Interact.

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“…The common eider ( Somateria mollissima ) is a marine benthic‐feeding diver, and it is considered a midtrophic predator, preying mainly on mollusks and other invertebrates (Larsen and Guillemette 2000; Houle et al 2017). Because of its marine diet, the common eider is expected to serve as a good representative of contaminant exposure in the marine food web (Fenstad et al 2016), although this is as a benthic midtrophic level feeder, not of the same part of the food web as the mainly fish‐eating herring gulls.…”

Section: Introductionmentioning

confidence: 99%

Common Eider and Herring Gull as Contaminant Indicators of Different Ecological Niches of an Urban Fjord System

Thorstensen

Ruus

Helberg

et al. 2020

Integr Envir Assess & Manag

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Seabirds like gulls are common indicators in contaminant monitoring. The herring gull (Larus argentatus) is a generalist with a broad range of dietary sources, possibly introducing a weakness in its representativeness of aquatic contamination. To investigate the herring gull as an indicator of contamination in an urban-influenced fjord, the Norwegian Oslofjord, we compared concentrations of a range of lipophilic and protein-associated organohalogen contaminants (OHCs), Hg, and dietary markers in blood (n = 15), and eggs (n = 15) between the herring gull and the strict marine-feeding common eider (Somateria mollissima) in the breeding period of May 2017. Dietary markers showed that the herring gull was less representative of the marine food web than the common eider. We found higher concentrations of lipophilic OHCs (wet weight and lipid weight) and Hg (dry weight) in the blood of common eider (mean ± SE ∑PCB = 210 ± 126 ng/g ww, 60 600 ± 28 300 ng/g lw; mean Hg = 4.94 ± 0.438 ng/g dw) than of the herring gull (mean ± SE ∑PCB = 19.0 ± 15.6 ng/g ww, 1210 ± 1510 ng/g lw; mean Hg = 4.26 ± 0.438 ng/g dw). Eggs gave opposite results; higher wet weight and lipid weight OHC concentrations in the herring gull (mean ± SE ∑PCB = 257 ± 203 ng/g ww, 3240 ± 2610 ng/g lw) than the common eider (mean ± SE ∑PCB = 18.2 ± 20.8 ng/g ww, 101 ± 121 ng/g lw), resulting in higher OHC maternal transfer ratios in gulls than eiders. We suggest that the matrix differences are due to fasting during incubation in the common eider. We suggest that in urban areas, herring gull might not be representative as an indicator of marine contamination but rather urban contaminant exposure. The common eider is a better indicator of marine pollution in the Oslofjord. The results are influenced by the matrix choice, as breeding strategy affects lipid dynamics regarding the transfer of lipids and contaminants to eggs and remobilization of contaminants from lipids to blood during incubation, when blood is drawn from the mother. Our results illustrate the benefit of a multispecies approach for a thorough picture of contaminant status in urban marine ecosystems.

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Food Habits of Flightless American Eiders (Somateria mollissima dresseri) in Québec, Canada

Cited by 2 publications

References 19 publications

Predicting eider predation potentials on mussels in Danish coastal areas—implications for mussel farming site-selection

Predicting eider predation potentials on mussels in Danish coastal areas—implications for mussel farming site-selection

Common Eider and Herring Gull as Contaminant Indicators of Different Ecological Niches of an Urban Fjord System

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