Stable-isotope ratios of blood components from captive northern fur seals (<i>Callorhinus ursinus</i>) and their diet: applications for studying the foraging ecology of wild otariids
Bibliographic record
Abstract
Stable nitrogen and carbon isotope ratios (13C/12C and 15N/14N, respectively) of plasma, serum, clotted red blood cells, and unclotted red blood cells from six captive northern fur seals (Callorhinus ursinus) and two fish species in their diet, Atlantic herring (Clupea harengus) and Icelandic capelin (Mallotus villosus), were measured. The δ15N values from the fur seal blood components ranged from 15.5 ± 0.1 (mean ± SE; all RBCs) to 16.7 ± 0.1 (plasma), and δ13C values ranged from 18.3 ± 0.1 (serum) to 17.5 ± 0.1 (clotted RBCs). Fur seal blood components had higher δ15N and δ13C values than their diet. Mean enrichments of 15N between fur seal RBCs and plasma/serum and their prey were +4.1 and +5.2, respectively, while mean 13C enrichments were +0.6 (serum), +1.0 (plasma), and +1.3 to +1.4 (all RBCs). Fur seal blood components did not differ in δ15N or δ13C between the sexes. One female (Baabs) was pregnant at the time of sampling and was resampled 4 months later, when she was approximately 3 months post parturient. The δ15N values of the blood components taken from Baabs during pregnancy were all higher by 0.6 (unclotted RBCs) to 1.3 (plasma) than those of samples taken during lactation, while her δ13C values were nearly the same (RBCs) for the two time periods or lower during lactation by 0.5 (serum) and 0.7 (plasma). This study was the first to analyze isotope ratios of blood components from captive fur seals and their prey. The subsequent establishment of fractionation values between captive fur seals and their diet can be used to interpret trophic level and habitat usage of otariids feeding in the wild.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".