Origin, Postrelease Survival, and Imprinting of Pen-Acclimated and Direct-Stocked Chinook Salmon in Lake Ontario
Bibliographic record
Abstract
Abstract We determined the stocking origin of the Chinook Salmon Oncorhynchus tshawytscha harvest and compared the relative survival and tributary returns of pen-acclimated and direct-stocked salmon at eight sites in Lake Ontario. Chinook Salmon parr were coded-wire-tagged in 2010, 2011, and 2013, and adult salmon were recovered in the lake and tributaries from 2011 to 2017. Lake harvest counts indicated that pen acclimation provided significantly better smolt-to-lake harvest survival, with averages of 1.7, 2.3, and 2.3 times greater contribution (SE = 0.15, 0.21, 0.23), respectively, to the lake fishery than direct stocking. After accounting for lake survival, pen acclimation also provided significantly better smolt-to-adult return rates to tributary harvest than direct stocking at some sites, with average return ratios of 0.8, 1.1, and 1.6 (SE = 0.2, 0.2, 0.3), respectively, for the three year-classes. Port-specific lake harvest from June to August consisted of salmon stocked at sites throughout the lake, indicating a well-mixed population prior to the prespawn staging period. Of the eight lake ports analyzed, a minority of the Chinook Salmon harvested by anglers in June–August were stocked at each site (mean = 13%, SE = 2%) or at nearby sites (mean = 22%, SE = 4%), with most originating from stocking sites greater than 30 km away. In September, stocked Chinook Salmon became more segregated in the lake, with harvest at each site consisting of a higher percentage (mean = 38%, SE = 4%) of salmon stocked at those sites and nearby sites (mean = 29%, SE = 5%), suggesting that salmon began staging in this period. In contrast, most salmon harvested by tributary anglers in October were stocked at those sites (mean = 67%, SE = 4%), indicating good imprinting of both pen-acclimated and direct-stocked Chinook Salmon. Most strays in tributaries were from nearby stocking sites. Increased Chinook Salmon catch rates in the lake fishery coincided with increased use of pen acclimation and a declining prey fish population, underscoring the importance of evaluating outcomes of new stocking policies that may increase predator survival and predation pressure on prey.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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".