Understanding how winter conditions in the North Atlantic affect the physiology and behaviour of Atlantic Salmon in sea-cages
Bibliographic record
Abstract
In recent years there have been a number of instances where declines in water temperature are suspected to have contributed to winter mortalities at salmon cage-sites in Atlantic Canada. In addition, it is expected that temperature variability due to more intense and frequent winter storms will increase with climate change, and this may further threaten Atlantic salmon health and welfare in sea-cages. To better understand cage-site conditions and aspects of salmon behaviour and physiology during the winter, we fitted Atlantic salmon in commercial size sea-cages in Newfoundland (Canada) for two consecutive years with internal and external data storage tags (DSTs) that recorded depth, temperature, heart rate ( f H ) and 3D-acceleration (swimming activity). Tags were surgically attached / implanted in late October / early November when water temperatures were 8–10 °C, and the DSTs were collected at the time of harvest. Although tag retrieval was limited due to some early mortality, challenges due to Covid-19 and with fish identification during harvest, the data collected for both years were comparable. Water temperature decreased at a rate of 0.35–0.57 °C week −1 from October / November to March, and the coolest average weekly temperature experienced by the fish was 1.10 °C in early March of both years. Average f H decreased with temperature starting in the fall, and the fish primarily occupied the upper 5 m of the cage for the duration of this study, despite the fact that temperatures were generally homogeneous with depth. Nonetheless, vertical migrations to deeper depths were observed during some periods (e.g., at night during the coldest months), and thus, the average depth of the fish was greater during these times. These data reveal that temperatures in sea-cages in Newfoundland remain below 5 °C for ∼5 months and are below 2 °C for ∼1.5 months. Thus, understanding how cold temperatures affect various aspects of salmon biology, and monitoring these fish during this period, is critical to the sustainability and future of this industry. • Sea-caged salmon were monitored during the fall/winter using Star-Oddi data loggers. • Water temperatures fell by 0.35–0.57 °C week −1 and were below 5 °C for 5 months. • Heart rate closely followed the temperature decline. • Fish mainly occupied the upper 5 m of the cage with excursions to deeper depths. • Fish activity was higher during the day, but reduced at temperatures below 5 °C.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".