Investigating a movement strategy for Greenland halibut (Reinhardtius hippoglossoides) in the Canadian Arctic Offshore
Notice bibliographique
Résumé
Movement is a universal characteristic of all organisms. It is critical as it facilitates life’s events from feeding to reproduction, ultimately shaping the structure and function of populations. However, studying the movements of highly mobile marine species that travel across open environments is inherently difficult. This leaves many basic questions such as, where, when, and why species move, unanswered and limits our grasp of their ecology. Accordingly, this dissertation focuses on Greenland halibut (Reinhardtius hippoglossoides), a large, highly mobile flatfish found in abundance in the Eastern Canadian Arctic. In Baffin Bay, Nunavut, Greenland halibut are thought to use the offshore environment as a travel corridor as they migrate between habitats for spawning and non-spawning reasons. However, while the study of Greenland halibut obtained from inshore areas has greatly advanced our understanding of spatial-temporal movement patterns associated with those environments, there is a knowledge gap regarding the fine-scale characteristics of movement for fish directly obtained from the offshore. Chapter 2 of this dissertation provides an analysis of the first detections of offshore obtained, acoustically tagged Greenland halibut recorded on an extensive, novel acoustic telemetry array in offshore Baffin Bay, to understand where and when fish are moving. We found evidence for high mobility in the offshore, as well as systematic movement behaviour based on seasonal, latitudinal, and multi-year return detection patterns. Chapter 3 uses the same detection dataset as presented in Chapter 2 to test if offshore-tagged Greenland halibut exhibit a unified movement strategy along the offshore banks of Baffin Bay as a route to travel south to Davis Strait. Through an evaluation of the data with sequence analysis and hierarchical clustering methodology, we found little evidence to support the unified movement hypothesis and demonstrated that movements are variable with inshore-offshore connectivity. Chapter 4 examines the design of the offshore acoustic telemetry array as a potential driver of detection gaps identified in Chapters 2 and 3, given variable spacing between offshore receiver moorings and non-overlapping detection ranges where fish could be swimming undetected. This field experiment found little evidence to suggest that an intensive array design was detecting more fish than the original array design, suggesting again that Greenland halibut are likely undertaking a variety of movement paths in the offshore. Chapter 5 investigated movement through the analysis of stable isotopes derived from tissues of Greenland halibut sampled at discrete locations around the offshore. Here we found evidence for potential broad-scale southern movements for Greenland halibut and suggest a high degree of complexity between Greenland halibut physiology and movement given the unexpected relationships between stable isotopes and measures of body condition. Overall, this dissertation fills a knowledge gap in our understanding of the movements of Greenland halibut in offshore Baffin Bay. Further, given the commercial importance of Greenland halibut in inshore and offshore Baffin Bay, this work also provides findings applicable for fisheries management.
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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 | 0,002 | 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 ».