Age-specific survival, abundance, and immigration rates of a Weddell seal (<i>Leptonychotes weddellii</i>) population in McMurdo Sound, Antarctica
Bibliographic record
Abstract
Since the 1960s, Weddell seals (Leptonychotes weddellii (Lesson, 1826)) have been tagged and surveyed annually in McMurdo Sound, Antarctica. Markrecapture analyses and model selection trials using Akaike's Information Criterion indicate that sex, cohort, and year affect juvenile (ages 1 and 2) survival. In contrast, year and perhaps sex and cohort are less important factors for adult survival. Average annual survival is higher among adults (0.93) than juveniles (0.550.59) and there is little evidence for senescence to at least age 17. The oldest known-aged female and male in the study were 27 and 24 years old, respectively. Data suggest that the abundance of a resident population of Weddell seals remains relatively stable over time despite annual fluctuations in JollySeber abundance estimates for the entire population. We argue that this annual variability is likely the result of temporary immigration of animals born outside the study area; mean rates are estimated from a simulation model and tagging data to be between 16.8% and 39.7% for females and between 13.1% and 31.6% for males. Sea ice extent appears to affect immigration where, during times of reduced fast-ice, immigrants are forced, or allowed easier access, into the ice-covered areas of Erebus Bay from surrounding locations. Our findings contradict previous studies reporting lower survival and higher immigration. Model choice is shown to be the most likely cause of these discrepancies and we provide evidence that our models are more appropriate than those used elsewhere.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.000 | 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 teacher head, 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".