Assessing the impact of a recent predatory invader: The population dynamics, vertical distribution, and potential prey of <i>Cercopagis pengoi</i> in Lake Ontario
Bibliographic record
Abstract
The predatory impacts of Cercopagis pengoi , a planktivorous cladoceran first observed in Lake Ontario in 1998, were assessed by examining patterns in the distribution and population dynamics of macrozooplankton. Specifically, we determined the vertical distribution of C. pengoi in Lake Ontario with respect to other zooplankton species and possible biotic and abiotic controlling factors and used seasonal time series of potential prey species, both before and after C. pengoi invasion, to make inferences about predatory impacts of C. pengoi . The highest abundances of C. pengoi generally occurred at the bottom of the epilimnion or at the top of the metalimnion, and strong diel vertical migration was not observed. The vertical distribution of cyclopoid and calanoid nauplii and copepodids was deeper in 1999 than had historically been observed, which suggest possible avoidance of C. pengoi or localized predatory depletion. Seasonal analyses of normalized biomass size spectra from the Bay of Quinte supported an impact of C. pengoi on organisms <0.1 µg dry weight. The hypothesized predatory effect on juvenile copepods was supported by an analysis of seasonal time series, where we observed that high abundances of C. pengoi coincided with marked decreases in these groups. Consequently, the presence of C. pengoi likely decreases the production of juvenile copepods both through direct predation and through a shift of copepod vertical distribution to colder waters. Among the cladocerans, only Bosmina longirostris abundance declined in the presence of C. pengoi in the analysis of seasonal time series.
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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 | 0.001 |
| 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 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".