Characteristics and Spatial Segregation of Sympatric Saugers and Walleyes in the Ottawa River, Canada
Bibliographic record
Abstract
Abstract Few comparative studies exist on the sympatric populations of Saugers Sander canadensis and Walleyes S. vitreus, especially in northern rivers. Depth-stratified, standardized index netting surveys were conducted in the Ottawa River, Canada—a large, fragmented northern river. The objectives of this study were to (1) determine whether Saugers and Walleyes were spatially segregated within river reaches; (2) assess whether relative abundances of the two species were correlated within river reaches and ascertain factors affecting their relative abundances; (3) determine whether life history characteristics in this northern river were within the variation reported for each species; and (4) evaluate whether there was synchrony in year-class strength between the two species and identify the factors affecting year-class strength. Saugers and Walleyes were spatially segregated, specifically by depth. Probability of capture was greatest in the 20–35-m depth stratum for Saugers and in the 6–12-m depth stratum for Walleyes. Relative abundances of Saugers and Walleyes were correlated and were positively related to reach characteristics (i.e., mean and maximum depth, reach length, and river kilometers upstream from the confluence) but negatively related to thermal conditions (i.e., growing degree-days, water temperature at preferred depths, and human population in proximity to the river). Life history characteristics were within the literature-reported ranges except for Saugers, which were older with a smaller length at 50% maturity. Year-class strengths of Saugers and Walleyes were synchronous at the reach and river levels and were positively correlated with mean annual temperature but negatively correlated with mean annual river flow. Saugers and Walleyes can coexist within large water bodies. Recruitment synchrony suggests that spawning management efforts could benefit both species, which could be advantageous when managing the Sauger, a lesser studied species. However, life history differences advocate that harvest regulations (e.g., size limits) must be species specific in order to be effective. Received June 13, 2013; accepted January 27, 2015
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".