An evaluation of hot-iron branding as a permanent marking method for adult New Zealand sea lions, Phocarctos hookeri
Bibliographic record
Abstract
Context Studies of the population and behavioural ecology of pinnipeds require the ability to identify individuals over periods ranging from a single season to an entire lifetime. Aims The aims of this research were to examine the efficacy of hot-iron branding as a permanent marking technique including the legibility of marks over time and comparing estimates of survival for animals marked with brands versus flipper tags. Methods Adult female New Zealand sea lions (n = 135) aged between 4 and 24 years of age were hot-iron branded with four-digit numbers during the austral summer of 2000. Key results Ten years on, 100% of animals still alive could be identified from these brands. Over the 10-year research period, it was observed that the skin of fully healed individual brands could, on occasion, become lacerated due to injuries received from shark bites and/or bites from other sea lions, removing or temporarily reducing the legibility of single characters of some brands. However, these animals were still identifiable when all digits were considered – and scars could become an identifying mark in their own right. Key conclusions Survival estimates derived from branded versus tagged-only individuals were similar, although the variance associated with tagged-only survival estimates was higher, giving less robust estimates. This is likely a result of higher resight probabilities observed for branded individuals. Resighting of tags requires a close approach with a high associated level of disturbance to both the marked animal and those associated with it, especially when considered over the lifetime of the animal, while brands can be read from a considerable distance with little or no disturbance. Implications Thus, hot-iron branding can be an effective method for permanently identifying sea lions that provides robust parameter estimates, causes low disturbance in the resighting process, and does not compromise survival.
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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 | 0.001 | 0.002 |
| 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 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".