Assessment of the Îles-de-la-Madeleine Atlantic Surfclam Stock in 2023
Notice bibliographique
Résumé
The Atlantic Surfclam fishery in the Îles-de-la-Madeleine is conducted with hydraulic dredges in sub-areas 5A1 and 5B1 or using hand tools, on foot or while diving, in about 10 shellfish areas located in lagoons or near coasts. Hydraulic dredge fishery Three beds are currently known in sub-areas 5A1 and 5B1. The Chenal de la Grande-Entrée (CGE) and East beds are located in sub-area 5A1, and the North bed straddles sub-areas 5A1 and 5B1. Since 2012, harvesting has been mainly focused on the North bed, but resumed on the CGE bed in 2019. Over the past three years (2021–2023), the number of active harvesters has fluctuated between two and four, whereas it was between three and four for 2018–2020. Total allowable catches (TACs) have not been reached in sub-areas 5A1 and 5B1 since 2019, and average landings for 2021–2023 (177 t) are below the historical average (193 t, 2002–2020). The drop in landings is partly due to the decline in the number of active fisherman. When harvesting resumed on the CGE bed in 2019, the non-standardized catch per unit effort (CPUE) was high (347 kg/h.m). Although the average for the last three years (232 kg/h.m) is above the historical average (176 kg/h.m, 2002–2020), it shows a downward trend. For the North bed, CPUE was high in 2021 (330 kg/ h.m), but has been falling since. The average 2021–2023 (215 kg/h.m) is slightly below the historical average (233 kg/h.m, 2002–2020). Landed surfclam sizes remain stable and over 130 mm in all sampled beds. In recent years, the dredged area has decreased on the North bed, but it has increased on the CGE bed, with the resumption of harvesting in 2019. The proportion dredged of the known surface area of the North bed has varied between 2% and 3%, and that of the CGE bed between 7% and 10% between 2021 and 2023. Since 2002, fishing effort is sporadic and low in sub-areas 5A2 and 5B2; stock status is therefore unknown in these two sub-areas. Declining landings and CPUEs in recent years suggest that harvesting rates may be too high in sub-areas 5A1 and 5B1, despite shifting some of the fishing effort between the harvested beds (CGE and North). Hand digging Commercial and recreational clam digging by divers and shore harvesters is well-developed in the Îles-de-la-Madeleine. However, the extent of manual recreational harvesting is not well known. Reported commercial landings from hand digging vary with fishing effort. Between 2021 and 2023, average landings for diving (37 t) and hand digging (14 t) remained above their historical averages (2002–2020) of 22 t and 11 t, respectively. For dive harvesting, CPUEs in the two most harvested areas are relatively stable (46 kg/h in A-09.5) or increasing (72 kg/h in A-12.1) compared with their historical averages (2005–2020) of 54 and 69 kg/h.m, respectively. The average size of surfclams landed has also been stable at about 130 mm in 2021–2023. For shore harvesting, CPUEs in A-09.5 and A-17.1 have increased to 33 and 26 kg/h (2021–2023), compared with their respective historical averages of 26 and 21 kg/h (2005– 2020). The average size of surfclams landed has been around 120 mm for the last three years. The number of inactive licences relative to the number of licences issued (latent effort) is still high for both dive (88%) and shore (69%) harvesting. It is unclear whether the resource in the shellfish areas could support the deployment of the total fishing effort. Based on this information, hand harvesting could be maintained at the current level. Any measures that will help better document hand digging fishery are desirable.
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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 | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 ».