Evaluation of Hatchery versus Wild Sockeye Salmon Fry Growth and Survival in Two British Columbia Lakes
Bibliographic record
Abstract
Abstract We evaluated the relative success of sockeye salmon hatchery fry stocking in two British Columbia–Alaska transboundary lakes (1,622-ha Tatsamenie Lake and 492-ha Tahltan Lake). Fry stocking began in the late 1980s and is still under way. During the study period, survival patterns in the two lakes were different. At Tatsamenie Lake, wild egg-to-fry survival was higher than hatchery egg-to-fry survival (11.3% versus 4.3%) and wild egg-to-smolt survival was higher than hatchery egg-to-smolt survival (5.8% versus 2.5%). We found no relationship between fry survival and stocking date, spawner abundance, or food availability in Tatsamenie Lake, but we did find a significant positive relationship between early-spring fry length and egg-to-fry survival. Also, we found that in net-pen experiments, larger fry survived better. From this, we concluded that hatchery fry stocked into Tatsamenie Lake may suffer from size-mediated mortality and that net-pen supplemental feeding could be used to overcome this problem. However, because eggs used for hatchery production come from the lake, fry stocking can only be justified when hatchery fry survival exceeds wild fry survival. At Tatsamenie Lake, this goal has not yet been attained. At Tahltan Lake, wild egg-to-fry survival was lower than hatchery egg-to-fry survival (1.5% versus 6.3%) and wild egg-to-smolt survival was lower than hatchery egg-to-smolt survival (3.6% versus 12.8%). Hatchery fry release date and food availability both failed to explain these differences in fry and smolt survival at Tahltan Lake. However, there was a strong negative relationship between total female escapement and wild egg-to-smolt survival. This supported the results of an earlier investigation, which suggested that Tahltan Lake was spawning-site limited. We concluded that at Tahltan Lake, hatchery fry stocking increased smolt numbers, is biologically justified, and should be continued.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 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".