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Cited by 38Marine animal studies overviewWildlife Ecology and ConservationMarine and fisheries research

Prey Selection by Marine-Coastal River Otters (Lontra canadensis) in Newfoundland, Canada

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Cote, D., Stewart, H. M. J., Gregory, R. S., Gosse, J., Reynolds, J. J., Stenson, G. B., Miller, E. H.·2008·Journal of Mammalogy
DOI 10.1644/07-mamm-a-192.1
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Abstract

Previous studies have suggested that diets of river otters (Lontra canadensis) vary in response to seasonal shifts in prey availability, and that they select slowly moving fish of moderate size. To test these assumptions for marine-coastal river otters in Newfoundland, Canada, we reconstructed diets and estimated body length of important fish prey through analysis of otoliths and other hard parts recovered from scats collected in Bonavista and Placentia bays. Diet of otters in Bonavista Bay also was compared with the species and size composition of the nearshore fish community, as determined by concurrent beach-seine sampling. Diets were qualitatively similar but quantitatively different between bays. Otters consumed proportionally more cunner (Tautogolabrus adspersus) and stickleback (Gasterosteidae) in Placentia Bay, and more sculpin (Cottidae) and cod (Gadus) in Bonavista Bay. Flounder (Pseudopleuronectes americanus) was important in both bays, based on biomass, because individual fish in the diet were large. Fish-community composition in Bonavista Bay varied seasonally, a pattern that was not reflected in the diet, suggesting active selection of fish prey by otters. Slow-swimming fish (sculpin, flounder, and ocean pout [Macrozoarces americanus]/rock gunnel [Pholis gunnellus]) were overrepresented in the diet, and fast-swimming species (cod and hake [Urophycis]) were underrepresented. Otters also selected larger individuals within taxa. The lower limits at which size classes were incorporated into diet varied across fish species, and may reflect species differences in detectability by otters due to camouflage and behavior.

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  • River otters generally select for benthic, slow-moving aquatic prey available in high abundance, suggesting that they rely on a "risk averse" foraging strategy that focuses on consistently catchable prey rather than targeting species that might provide a greater energetic reward per capture.

    “River otters generally select for benthic, slow‐moving aquatic prey available in high abundance (Ryder 1955; Cote et al. 2008; Day et al. 2015), suggesting that they rely on a “risk averse” foraging strategy that focuses on consistently catchable prey rather than targeting species that might provide a greater energetic reward per capture (Pyke 1984).”

    From River Otter Predation of Nesting Seabirds Along the Coasts of North America (2025) · cites this paper as Cote et al. 2008

    Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

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  • Studies of river otter foraging strategies in primary freshwater habitats have shown that river otters consistently select for larger-bodied fish within individual taxa.

    “This result initially appears to contrast with studies of river otter foraging strategies in their primary freshwater habitats, where river otters have been shown to consistently select for larger‐bodied fish within individual taxa (Hansen 2003; Cote et al. 2008).”

    From River Otter Predation of Nesting Seabirds Along the Coasts of North America (2025) · cites this paper as Cote et al. 2008

    The Results report that larger individuals of each fish taxon were more common in otter scats than in samples of available fish. But this study examined marine-coastal habitats in Newfoundland, not primary freshwater habitats, so it does not establish the claim about freshwater studies. (LLM, conf=0.88)

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Research works printed but not linked: 34

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Authors
Cote, D., Stewart, H. M. J., Gregory, R. S., Gosse, J., Reynolds, J. J., Stenson, G. B., & Miller, E. H.
Affiliations
  • Memorial University of Newfoundland (CA)
  • Fisheries and Oceans Canada (CA)
  • Parks Canada (CA)
  • Government of Newfoundland and Labrador (CA)
ORCID
Venue
Journal of Mammalogy
Publisher
Oxford University Press (OUP)
Published
2008-08-15
Volume
89
Issue
4
Pages
1001-1011
ISSN
  • 0022-2372 (ISSN-L)
  • 1545-1542
DOI
10.1644/07-mamm-a-192.1
OpenAlex
W2157927687
Cited by
38
References
0
Citations by year
2026: 1 · 2025: 5 · 2024: 1 · 2023: 2 · 2022: 1 · 2021: 2 · 2020: 4 · 2019: 1 · 2017: 1 · 2016: 3 · 2015: 5 · 2014: 2 · 2013: 2 · 2012: 2
FWCI
1.73
Type
journal article
Language
en
Open access
Licence
cc-by-nc-nd
Locations
  • Journal of Mammalogy (publishedVersion, cc-by-nc-nd)
  • BioOne Complete (BioOne) (submittedVersion)
Funders
  • Parks Canada
  • Fisheries and Oceans Canada
Topics
  • Physical Sciences › Environmental Science › Ecology › Marine animal studies overview
  • Physical Sciences › Environmental Science › Ecology › Wildlife Ecology and Conservation
  • Physical Sciences › Environmental Science › Global and Planetary Change › Marine and fisheries research
Keywords
river otter, Lontra canadensis, prey selection, diet, fish prey, otolith analysis, scat analysis, fish community composition, seasonal diet variation, prey size selection, cunner, stickleback, sculpins, flounder, cod, Bonavista Bay, Placentia Bay, Newfoundland

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