Inferring long-term limnological changes linked to declining lake trout population in a remote Boreal Shield lake
Bibliographic record
Abstract
Sivarajah B, Pink O, Paterson AM, Jeziorski A, Griffiths KT, Rühland KM, Smol JP. 2025. Inferring long-term limnological changes linked to declining lake trout population in a remote Boreal Shield lake. Lake Reserv Manag. 41:143–161.We used bioindicators preserved in a dated lake sediment core to assess long-term limnological changes in a relatively remote, Boreal Shield lake in south-central Ontario, Canada. Tadenac Lake is minimally disturbed with no shoreline development, and the last major hydrological change occurred more than 100 years ago when the lake was permanently separated from Tadenac Bay (Georgian Bay, Lake Huron). In the late 1970s, anglers began reporting decreases in lake trout (Salvelinus namaycush) catch, and only one lake trout was observed in a 2014 fish survey. Both diatom compositional changes and a diatom-based inference model indicated a gradual decrease in pH since the construction of the permanent barrier in 1925. Since the second half of the 20th century, accelerated regional warming, with longer and warmer growing seasons and ice-free periods, have affected Tadenac Lake, as evidenced by (1) an increasing trend in spectrally inferred chlorophyll a, indicative of higher whole-lake primary production, and (2) diatom compositional changes and an increase in the index of chrysophyte scales to diatom valves, indicative of longer and stronger summer thermal stratification. Furthermore, chironomid-based inferences suggest that the hypolimnetic oxygen condition within Tadenac Lake deteriorated during the second half of the 20th century and may have negatively affected critical lake trout habitat. Overall, our study suggests that Tadenac Lake, a minimally anthropogenically disturbed site, has undergone notable limnological changes since the mid 20th century as a result of climate-mediated changes. These changes may have negatively influenced the lake trout habitat, which could have contributed to the observed decline in recruitment and catch. Our paleolimnological data from a remote lake highlight the importance of considering the long-term, gradual effects of climate-mediated changes on aquatic ecosystems, as this will aid in the development of effective habitat conservation and fisheries management strategies.
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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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".