NAFO Divisions 2J3KL Northern cod (Gadus morhua) stock assessment to 2024
Notice bibliographique
Résumé
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.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,002 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,009 | 0,002 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».