Species and size differences in the digestion of otoliths and beaks: Implications for estimates of pinniped diet composition

@article{Tollit1997SpeciesAS,
  title={Species and size differences in the digestion of otoliths and beaks: Implications for estimates of pinniped diet composition},
  author={D. Tollit and M. Steward and P. Thompson and G. Pierce and M. Santos and S. Hughes},
  journal={Canadian Journal of Fisheries and Aquatic Sciences},
  year={1997},
  volume={54},
  pages={105-119}
}
We examined the digestion of hard remains of between one and four different size ranges of nine key North Sea prey taxa fed to seven captive harbour seals (Phoca vitulina). Percentage length reduction (mean 27.5%) and recovery rates (mean 42%) of experimental otoliths varied between species and were positively correlated to fish size and otolith robustness (mass/length). Mean length reduction of egested otoliths increased systematically with increasing size of ingested whiting and sandeel… Expand
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TLDR
A simulation using actual dietary data showed that the overall diet composition was not radically changed by accounting for otolith digestion, although the apparent contribution of herring increased as the assumed digestion time is increased, because herring otoliths were the most susceptible to digestion. Expand
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TLDR
Differences in partial and complete digestion rates among prey species and between seal species highlight the importance of applying DCFs when reconstructing diet. Expand
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TLDR
Otoliths were more digested in carrier experiments; resulting digestion coefficients were greater than those from in situ experiments; consequently, the estimated proportion by weight of each species in the diet can change markedly when carrier, as opposed to in situ, digestion coefficients are used. Expand
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TLDR
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TLDR
A combination of the equations for otolith size to fish size from the two species avoided this anomaly and superseded previously published equations. Expand
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TLDR
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Estimation of grey seal ( Halichoerus grypus ) diet composition in the Baltic Sea
TLDR
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THE USE OF OTOLITHS AND VERTEBRAE IN THE IDENTIFICATION AND SIZE-ESTIMATION OF FISH IN PREDATOR-PREY STUDIES
TLDR
Relationships between the size of otoliths and vertebrae, and body length are presented for eleven teleost species of the north-east Atlantic and linear and non-linear functions provided the best fit for relations between hard structure size and fish length. Expand
Investigating the biases in the use of hard prey remains to identify diet composition using antarctic fur seals (Arctocephalus gazella) in captive feeding trials
TLDR
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