Assessment of the west coast of Newfoundland (4R) herring stocks in 2021
Bibliographic record
Abstract
Based on preliminary data, landings of herring from the west coast of Newfoundland (NAFO Division 4R) totaled 4,862 t in 2020 and 3,074 t in 2021, with an annual total allowable catch (TAC) of 20,000 t. The fishery experienced difficulties due to a high incidence of herring below the legal size. The proportion of spring-spawners in the landings increased from a time-series low of 1.6% in 2014 to 89.6% in 2021. The proportion of spring spawners in the summer and fall acoustic surveys also increased from an average of 7.3% for the 2009-2017 period to an average of 44.6% in 2020 (summer: 44.8%, fall: 40.6%) and 51.5% in 2021 (summer: 229 %, fall: 75.4%). Landings of spring-spawning herring in 2020 and 2021 were mainly composed of fish of the 2013 year-class (age 7-8), and to a lesser extent of fish of the 2017 year-class (age 3-4). The acoustic survey biomass estimates of spring-spawning herring in 2020 and 2021 were mainly composed of fish of the 2017 year-class (age 3-4). Landings of fall-spawning herring in 2020 and 2021 were mainly composed of fish aged 9 years and over. The acoustic survey biomass estimates of fall-spawning herring were dominated by the 2016 year-class in 2020 (age 4) and 2021 (age 5). The 2021 summer acoustic survey was dominated by fish aged 8 years and over. The mean fork length at which 50% of individuals were mature (L50) was respectively 24.5 cm and 25.4 cm for spring and fall spawners. These values are higher or near the current minimum size limit of 24.76 cm in the commercial fishery. The L50 of both spring- and fall-spawning stocks has varied around the long-term average since the 2000 year-class. Both spring- and fall-spawning herring stocks show a downward trend in mean length-at-age and weight-at-age since the beginning of the 1990s. Since 2014, the relative condition index of the two spawning stocks is below the series’ average. The condition of both herring spawning stocks is positively related to the abundance of large-bodied copepod species. The acoustic surveys estimated the highest biomass indices since the beginning of the survey in 2021 for spring spawners (122,145 t, 95% CI: ± 20,803 t) and in 2020 for fall spawners (226,005 t, 95% CI: ± 35,507 t). These values represent minimum estimates of the amount of fish available at the time of the survey. The ratio of the biomass fished over the highest biomass index estimated in the acoustic surveys was considered to be a proxy for the maximum exploitation rate. In 2020 and 2021, the maximum exploitation rate was respectively 1.1% (1.0-1.2%) and 2.4% (2.0-2.9%) for spring spawners, and 1.7% (1.4-2.0%) and 0.2% (0.1-0.2%) for fall spawners. If the 20,000 t TAC had been taken in 2020-2021, the maximum exploitation rates would have resulted in 4.5-15.6% (4.2-19.1%) for spring spawners and 1.2-6.8% (1.0-8.0%) for fall spawners. Available evidence up to 2021 (low exploitation rates, commercial and acoustic survey catch-at-age, age- and length-at-maturity) indicates that maintaining the TAC at status quo should not pose a significant short-term risk to herring stocks in 4R.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".