NAFO Divisions 2J3KL Northern cod (Gadus morhua) stock assessment to 2024
Bibliographic record
Abstract
Status The 2024 Spawning Stock Biomass (SSB) is 1.2 (95% Confidence Interval [CI] = 0.7–2.1) times the Limit Reference Point (LRP). There is an estimated 22% probability that the stock is in the Critical Zone. An upper stock reference has not been defined, however given the proximity to the LRP the stock is considered to be in the Cautious Zone. Trends Following a period of growth from 2010 to 2016, SSB has remained unchanged. SSB in 2024 is estimated at 342 Kt (95% CI = 246–475 Kt). Estimated numbers of recruits (age 0) have remained unchanged since the mid-2010s, corresponding to about 80% of pre-collapse (1954–90) levels. Natural mortality (M, ages 5+) has varied between 0.29 and 0.90 since 1995 (mean = 0.47) and in 2023 was above average [0.59 (95% CI = 0.32–1.12)]. Fishing mortality (F, ages 5+) has been below 0.05 since 2004 and in 2023 was 0.02 (95% CI = 0.01–0.03). Ecosystem and Climate Change Considerations The Newfoundland and Labrador (NL) ocean climate varies on near-decadal timescales with cooling and warming phases known to impact ecosystem productivity. The ongoing warming phase since about 2020 has likely contributed to improved conditions observed at the lower trophic levels (i.e., phytoplankton, zooplankton). The NL bioregion continues to experience overall low productivity as measured by the DFO research vessel (RV) survey, with biomass indices well below pre-collapse levels. While groundfish rebuilding has been observed since the mid-2000s, this process has not been continuous, with declines in the late-2010s. Trends over the last five years show improvements from recent lows. Northern cod productivity is linked to Capelin availability. Capelin collapsed in 1991 and has yet to recover, with the current stock size around 10% of pre-collapse levels. Capelin is expected to remain at current levels in the short term, impeding cod stock growth. Stock Advice SSB projections to 2027 with zero to two times the model estimated total removals for 2023 of 13,517 t show the probability of the stock declining into the Critical Zone increases from 42% with zero removals to 52% if removals are doubled. With total removal levels examined here (0 to 27,033 t) the risk of stock decline from 2024 to 2027 is moderately high to high, ranging from 62% to 76%. There is no level of removals that gives a neutral to high (≥50%) probability of stock growth. Under current ecosystem conditions and total removals the stock has not grown since 2016 and short-term prospects for stock growth are limited even under zero removals. Although primarily driven by ecosystem factors and natural mortality, increases in removals further add to the risk of stock decline into the Critical Zone.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.009 | 0.002 |
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".