Risk assessment model for dispersion of ballast water organisms in shelf seas
Bibliographic record
Abstract
The recommendation of mid-ocean exchange of ballast water has resulted in significant release of aquatic invasive species in shelf areas. This paper describes a semiquantitative risk assessment model developed for dispersion of ballast water organisms in shelf seas. The model simulates ballast water exchange as the release of tracer into the surface layer of a circulation model of the Scotian Shelf and Gulf of Maine. Three metrics are proposed to describe the risk of invasion: (i) the time-integrated concentration at a given location (the cumulative exposure index); (ii) the time taken for organisms to reach a given area (the invasion time); and (iii) the onshelf average concentration. A risk equation is derived that computes the relative overall risk of invasion for exchange segments along vessel tracks. Model results confirm the choice of offshelf alternate ballast water exchange zone advised by Department of Fisheries and Oceans, Canada. Low risk segments tend to be adjacent to one another. A four- to eight-fold reduction in invasion risk is possible, although this is likely a lower bound because of the use of monthly mean velocity fields. The model can be run in an operational mode to provide real-time risk assessment for vessel ballast water exchange.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".