Acoustic telemetry tracking of Coho Salmon smolts released from a community-run hatchery into a marine inlet reveals low early ocean survival
Bibliographic record
Abstract
Abstract Objective Hatcheries are used to help supplement populations of Pacific salmon Oncorhynchus spp. for conservation and fisheries purposes and to provide stewardship opportunities. In British Columbia, small community-run hatcheries typically focus on the latter and generally do not know the efficacy of their release approaches, unlike larger production hatcheries. Methods We used acoustic telemetry to track the survival and behavior of 90 hatchery-reared Coho Salmon O. kisutch smolts, released from a community hatchery, through Burrard Inlet and into the Strait of Georgia. This is the first study to track Coho Salmon smolts released directly into a marine environment and one of very few studies to track them in an oceanic setting. Result Smolt survival was lowest through the first 3 km of the migration at 37%, and the estimated cumulative survival to the final array (~20 km from release) was 10–23%. The presence of numerous predators in the region suggests that predation is a possible explanation for poor survival over the relatively short migration distance. Travel rates ranged from ~4 to 18 km/day, depending on the migration segment, which is slower than the marine migration of smolts from other species, likely increasing exposure to predators. However, we found potential evidence of “predator swamping,” as survival estimates across migration segments were highest for the final of our three release groups and poorest for the first release group, with intergroup survival estimates increasing by 7–12% in the final three migration segments. Releasing smolts at high densities and at night, as our partner hatchery currently does, likely improves smolt survival. Conclusion Our work demonstrates how acoustic telemetry can be used to examine hatchery practices and propose potential improvements. Saltwater readiness and the release location are factors that our results suggest may warrant future attention to potentially improve marine survival of Coho Salmon smolts.
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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 | 0.001 |
| 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) | 0.001 | 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".