Assessment of the northern contingent of Atlantic Mackerel (Scomber scombrus) in 2020
Bibliographic record
Abstract
The status of the northern contingent of Atlantic mackerel (Scomber scombrus) in the Northwest Atlantic is assessed every two years using an age-structured stock assessment model. This document presents the background information, data, and methods used to calculate the main stock status indicators for mackerel which form the basis of advice given to the Fisheries and Aquaculture Management Branch of Fisheries and Oceans Canada (DFO) in the setting of Total Allowable Catch (TAC). The present stock assessment took place on the 25-26 of February and March 3rd of 2021 and provides advice for the 2021-2022 fishing seasons. The main results of this assessment indicated that in 2020, the spawning stock biomass (SSB) of mackerel was estimated to be at an all-time low and in the Critical Zone, as per DFO’s Precautionary Approach (PA), since 2011. Recruitment of age 1 fish was estimated to be near record lows in recent years and the age structure of the stock was severely truncated. The fishing mortality rate (F) was also above the reference point. Short-term projections indicated that the probability of the SSB leaving the Critical Zone by 2023 varied from 29%-37% (TAC = 10 000 t) to 51%- 58% (TAC = 0 t) depending on the assumptions of future recruitment.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".