Investigating a movement strategy for Greenland halibut (Reinhardtius hippoglossoides) in the Canadian Arctic Offshore
Bibliographic record
Abstract
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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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".