Prey composition impacts lipid and protein digestibility in northern fur seals (Callorhinus ursinus

The done on freeze-dried samples, and total lipid content and total duration of the acclimation phase was designed to be sufficient crude protein content are expressed as percentage of total dried for the northern fur seals to adjust to the new diet and eliminate sample. [...] ADCn is calculated using the fol- The expected digestibility coefficients of both lipid and crude pro- lowing formula: tein of mixed-species diets were calculated (except for herring + magister squid diet) from the observed ADC of the single-species Ci × Nf ADC 1 × 100 diet counterparts, weighted by the proportion of the specific nu-n Cf × Ni trient in each prey item of the diet (Forster 1999). [...] Additionally, we from two of the northern fur seals (consuming different diets) also tested for statistical differences between the expected digest- were outliers and their inclusion failed to fulfil the assumptions ibility (expected ADC ; %) and the observed digestibility (observed of the linear mixed-effects (LME) models; this was also confirmed nADCn; %) of both lipid and protein from the mixed. [...] Data for each diet trial are from six northern fur seals, with the exception of the HG and SQ diets from six northern fur seals, with the exception of HG and SQ diets that that were only consumed by four of the animals. [...] The relationships among sea- the performance and survival rates of both vertebrate and inver- surface temperature, the abundance of juvenile walleye pollock (Theragra tebrate consumers, due to the high breakdown cost and the chal- chalcogramma), and the reproductive performance and diets of seabirds at the lenge of discarding toxic remnants (Harper et al.