Analysis of the Flemish Cap cod fishery: monitoring of the consequences of the management decisions
Notice bibliographique
Résumé
The objective of this document is to present the necessary information to the SC to monitor the consequences of the implementation in January 1st 2021 by the Commission of the technical measures in fisheries targeting cod in Div. 3M. The technical measures implemented were the closure of the cod directed fishery in Div. 3M in the first quarter of the year and the use of sorting grids in the cod directed trawl fishery. Data from the haul by haul database in the period 2016-2022 provided by the NAFO Secretariat have been used to study the situation before (2016-2020) and after (2021-2022) the measures were in place in the cod directed fisheries and in the fisheries with bycatch of cod. Also, the length and age distributions used in the assessment of this stock have been analysed. It should be noted that, apart from the technical measures implemented since 2021, in the 2021-2022 period the TAC of 3M cod suffered a large reduction due to the stock situation. This large reduction in the TAC may make it difficult to interpret the changes observed in the fisheries after 2021, interfering in the interpretation of this analysis. In order to have a clear idea and describe appropriately the consequences of the implementation of technical measures, a longer series of data after implementation needs to be analysed. Prior to 2021, most of the cod catches from the directed fisheries were taken in the first quarter and in the east and southwest of the bank for the longliners and in the southwest for the trawlers. Since 2021 catches are mainly taken in the second quarter and they are concentrated in the central part of Flemish Cap bank for the longliners and in the southwest of Flemish Cap for the trawlers. Almost 100% of the cod catches made with longline gear have been made in hauls targeting cod both before and after the technical measures were implemented. In the case of cod catches made in trawl hauls targeting cod that percentage dropped from over 96% in the 2016-2020 period to 85-88% in the 2021-2022 period. No significant change has been observed after the implementation of the technical measures in the catch composition and bycatch levels of the hauls directed to cod neither by longline nor trawl gears. In both directed fisheries, longliners and trawlers, the percentage of catches and effort inside the VME polygons in 2021-2022 is much lower than in 2016-2020. The bycatch of cod in the longline hauls targeting other species is negligible in the whole period 2016-2022. Cod bycatch in trawl hauls targeting other species increased significantly after the technical measures were implemented, mainly in 2022. No major change has been observed in the spatial-temporal pattern of sets catching cod as bycatch before and after the implementation of the technical measures. The impact on vulnerable marine ecosystems of longline sets catching cod as bycatch is minimal in both periods. Regarding the trawl hauls catching cod as bycatch, it should be noted the increase in effort carried out within the VME polygons of sponges and large gorgonians in the southwestern part of the Flemish Cap in 2022. From the analysis of the total length and age distribution of the cod catches, it can be concluded that, after the implementation of the technical measures, in the longline the proportion of intermediate lengths (42-54 cm) and ages (4-5 years) has increased in the period of implementation of the technical measures, while the proportion of larger individuals (>99 cm) decreased. In trawling fishery, the proportions of smaller lengths (<45 cm) and the younger ages (1-3) have decreased after the implementation of the technical measures.
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 | 0,002 | 0,004 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,003 | 0,002 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
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 ».