Growth bands are an unreliable indicator of sea urchin age: Evidence from the laboratory and the literature
Bibliographic record
Abstract
Abstract Knowledge of urchin age structure is crucial for understanding their ecosystem impacts and improving their management. In sclerochronology, translucent and opaque growth bands (TGB, OGB) in urchin ossicles are used to estimate age. An essential premise for using this technique is that one TGB and one OGB are formed every year, independent of urchin size or ossicle type. TGB and OGB addition are associated with slow and fast growth, respectively, and assumed to be added seasonally due to changes in water temperature. However, these assumptions are not unanimously supported by experiments, and validation attempts have not generated consensus. We conducted an experiment on Strongylocentrotus droebachiensis to test the validity of these assumptions and reviewed the literature to assess the use and validation of sclerochronology in urchins. The experiment demonstrated that the addition of TGB and OGB was not strictly related to temperature and was not consistent across urchin size‐classes or ossicle types. TGB were added in response to temporary stress, and no distinction on the basis of band width or pigmentation could be made between natural TGB and stress‐induced TGB. Only 52% of articles that used sclerochronology for aging urchins attempted any validation, and when the methodology was put under scrutiny, it was usually found to be wanting. More detailed studies are needed to address variability in growth bands deposition and endogenous and exogenous factors affecting this process. Sclerochronology in urchins should not be used until standardized procedures are able to provide accurate and precise interpretation of growth band addition.
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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 | 0.001 | 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".