The effectiveness of conservation aquaculture in meeting recovery objectives for an endangered White Sturgeon population
Notice bibliographique
Résumé
ABSTRACT Objective Documenting the effects of hatchery practices on vital rates and abundance of hatchery-origin fish in the wild is important for adaptive management of aquaculture programs aiming to improve the status of wild populations. Here, we synthesize outcomes from a long-running (2001–2021) conservation aquaculture program for White Sturgeon Acipenser transmontanus in the Canada (CDN)–USA transboundary reach of the upper Columbia River. Methods A Bayesian multistate Cormack–Jolly–Seber model was used to estimate abundance, survival, movement, and harvest rates for 14 year-classes of hatchery-origin White Sturgeon. The model was fitted to 20 years of mark–recapture data from more than 140,000 PIT-tagged juveniles released from hatcheries in CDN and the United States between 2001 and 2014. Results There was substantive variation in survival and movement rates among year-classes, which in CDN was driven in part by increased competition from hatchery-origin fish. Survival rates of age-1 fish in CDN declined by fourfold over 7 years during a period when biomass of hatchery fish increased from 0 to 20 kg/ha. Movement rates out of CDN over this period increased by a similar amount. Releasing fish at 30 cm compared to 20 cm led to a fivefold increase in the survival rate to age 5. Age-1 survival rates for fish released in spring or summer were 6- and 27-fold higher compared to survival rates of fish released in fall or winter in CDN and the USA, respectively. Maternal family effects on survival rates were generally weak. Harvest fisheries in the USA reduced the abundance of over-represented year-classes by 44–92% between 2017 and 2021, but the extent of depletions was uncertain due to the limited number of PIT tag recoveries. In 2021, abundance of hatchery-origin fish was 60% higher in CDN (8,900) than in the USA (5,700) due to a combination of (1) higher stocking rates in CDN in the early years of the program and (2) removal of fish in the USA from recreational and tribal fisheries. Conclusions Evaluating the success of sturgeon conservation aquaculture programs requires decades of effort, and adaptive management is challenged by the much shorter time frames that decision makers are used to working with. Our study showed that conservation aquaculture for White Sturgeon in the transboundary reach has achieved some of its original goals in the first two decades of implementation by reducing the risk of extirpation and maintaining genetic diversity of the wild population. High stocking rates during the early years of the program resulted in lower survival of hatchery-origin fish in CDN, higher rates of movement of hatchery-origin fish from CDN to the USA, and lower somatic growth rates of hatchery- and wild-origin fish in both countries. These effects will likely persist for decades owing to the long lifespan of White Sturgeon. Natural spawning of hatchery-origin fish has yet to be documented but will likely begin about three decades after the start of the program. It will take at least four decades from the start of the program to determine whether hatchery-origin fish are increasing natural recruitment to the wild population. Our study underscores the importance of using a rigorous long-term adaptive management framework to evaluate recovery actions and potentially modify them over time.
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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 | 0,004 | 0,007 |
| 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 | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| 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 ».