Survival and migration patterns of naturally and hatchery‐reared Atlantic salmon (<i>Salmo salar</i>) smolts in a Lake Ontario tributary using acoustic telemetry
Bibliographic record
Abstract
Abstract Atlantic salmon ( Salmo salar ) smolts are often stocked into rivers to supplement natural reproduction, yet hatchery‐reared fish have lower survival compared to wild conspecifics. However, few studies have assessed riverine migratory performance and survival differences in hatchery and wild smolts, or more specifically naturally reared smolts (hatchery fish released earlier as parr), particularly in rivers with weirs which may further reduce survival. Using acoustic telemetry, including a subset of fish with novel transmitters that identify predation events, we assessed survival and migration patterns of hatchery‐ (2017: n = 32; 2018: n = 30) and naturally reared Atlantic salmon smolts (2017: n = 8; 2018: n = 30) in a Lake Ontario tributary with two weirs to better understand their ecology and assess the influence of environmental parameters on migration. Naturally reared smolts were 13.9 times more likely to survive than hatchery‐reared smolts and mark–recapture models indicated that weirs did not reduce survival for either group. Survival per km was lowest at the release site, indicating pre‐migration mortality, and specifically high stocking‐related mortality of hatchery‐reared smolts. Speed and times of day fish migrated (i.e. migratory performance) did not vary by rearing group, suggesting that the high mortality of hatchery‐reared smolts may be due to other factors related to hatchery and stocking operations. Overall mean (± SD ) migration speed for smolts was 0.70 ± 0.39 km/hr and movements occurred significantly more frequently at night (18:00–06:00). Smolts were detected in Lake Ontario after they left the river; however, the array in Lake Ontario was not conducive to providing much detail regarding movement patterns. There was no predation of the two predation tags detected in Lake Ontario, indicating that movements were made by smolts and not predators. With ongoing restoration efforts of Atlantic salmon in Lake Ontario, it was important to understand the smolt migration patterns and success of the stocked fish. Our findings of similar migratory performance yet different relative survival of hatchery‐ and naturally reared smolts help inform management with regards to stocking strategies that could improve Atlantic salmon reintroduction success.
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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".