Chinook in Southern Resident Killer Whale Critical Habitat
Notice bibliographique
Résumé
Chinook salmon are a key prey of Southern Resident Killer Whales (SRKW) and variability in individual traits (e.g., body size, lipid content) affects their nutritional value to SRKW. Spatiotemporal distribution, local abundance, and fish behavior may influence the accessibility and availability of Chinook salmon to SRKW. Using recreational fisheries data (2014-2023), a geostatistical model was developed to estimate the stock composition and the size composition of Chinook salmon within SRKW critical habitat in Canadian waters, during May-September, when SRKW diets are dominated by Chinook salmon. To investigate SRKW prey selectivity, a co-occurrence approach was taken to compare the size and stock composition of SRKW prey remains in relation to model estimates from recreational fishery samples, in the western portion of SRKW critical habitat from June to September (2017-2023). All Chinook salmon stocks observed in the recreational fisheries data occurred in SRKW prey remains. Fraser River Spring 52, Summer 52, and Summer 41 stocks were more common, while Puget Sound, West Coast Vancouver Island (WCVI), Columbia River Summer/Fall, and “Other” stocks were less common, in prey remains than predicted by the recreational fishery model. Chinook salmon estimated to be smaller than 75 cm fork length were rarely observed in SRKW prey remains. Chinook salmon greater than 75 cm fork length were more common, while fish between 55 and 75 cm fork length were less common than predicted by the recreational fishery model. While total terminal abundance summed across all stocks considered here has remained relatively stable since 1982, Fraser River Spring 52 and Summer 52 Chinook salmon populations have declined in abundance, while the Fraser River Summer 41 and WCVI stocks have increased in abundance. Puget Sound and Columbia River Summer/Fall abundance has varied cyclically. SRKW have poor body condition in the spring. In the current study, SRKW showed selectivity towards Chinook salmon stocks with high lipid content and Chinook salmon individuals with large body size. Therefore, improvements to the SRKW prey field in Canadian critical habitat may occur via increasing the abundance of Chinook salmon with early migration timing, high lipid content, and large body size. Independent of abundance, SRKW may also benefit from increases in prey quality as represented by the body size and/or lipid content of Chinook salmon stocks. Key sources of uncertainty in the SRKW prey remains data include potential sampling bias, as well as low precision due to a relatively small sample size. A key source of uncertainty associated with characterizing Chinook salmon available to SRKWs is the extent to which fisheries-dependent samples accurately represent the underlying prey base. The importance of Chinook salmon stocks outside of Canadian critical habitat and during other periods of the year was not considered here because prey remains samples were not available. Non Chinook salmon and other species present in SRKW diets were not evaluated and warrant additional research.
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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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 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) | 0,002 | 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 ».