Daily, Incremental Changes in Incubation Temperature Alter Metabolism and Hatchling Phenotype of Developing Lake Whitefish
Bibliographic record
Abstract
Temperature has pervasive effects on poikilotherm physiology, and embryos and newly hatched/born animals are especially vulnerable to temperature shifts. Lake whitefish ( Coregonus clupeaformis ) are a North American, freshwater lake species with lengthy (80–150 day, 2–8 °C) overwintering embryonic development. Stenothermic, cold‐water embryos may be particularly susceptible to thermal shifts caused by anthropogenic thermal effluent and climate change. We incubated whitefish embryos in petri dishes (N=2000, 6–10 replicates each treatment) at constant treatments of 2.0±0.1°C, 5.0±0.1°C, and 8.0±0.1°C (mean±SD), and in a variable temperature treatment (VT; N=500, each treatment). In the VT, a daily 2°C temperature change (2°C–4°C‐6°C–8°C and back from 8°C‐6°C‐4°C‐2°C) occurred throughout embryonic incubation (mean 5.0±0.3°C). Mortality was quantified as number of hatchlings÷starting embryo number, time to hatch (days post fertilization, dpf) was recorded, and hatchling yolk‐free dry mass was measured. Oxygen consumption rate (VO 2 ; N=8–10, each treatment) was measured at 60% of embryonic development and in hatchlings within 3 days post hatching. VO 2 was measured for the four treatments (2°C, 5°C, 8°C, VT) at each constant temperature of 2°C, 5°C, and 8°C to determine if V.O 2 of VT embryos resembled the VO 2 of other treatments. VO 2 was measured at 2°C, 5°C, and 8°C after exposing embryos/hatchlings from each treatment to a daily 2°C temperature change, if necessary, until embryos/hatchlings reached the measurement temperature; embryos/hatchlings remained at the measurement temperature for a 24 hr acclimation period, and VO 2 was measured. Mortality was significantly affected by treatment (KWRS, P<0.001, Steel‐Dwass post hoc ), with 8°C (14.8%±17.6) and VT hatchlings (83.2%±0.07) having a significantly reduced mortality compared to 2°C (88.4%±0.02) and 5°C (90.5%±0.04) hatchlings. Time to hatch (dpf) was significantly different across all treatments (1‐way ANOVA, P<0.001, Duncan post hoc ) ‐ 8°C (68±2), VT (111±4), 5°C (116±4), 2°C (170±3). Likewise, hatchling yolk‐free dry mass (mg) was significantly different across all treatments (1‐way ANOVA, P<0.001, Duncan post hoc ) ‐ 8°C (0.66±0.08), VT (0.97±0.06), 5°C (1.07±0.03), 2°C (1.36±0.04). VO 2 was significantly affected by the interaction between treatment and measurement temperature (2, 5, 8 °C) at 60% of embryonic development and for hatchlings (2‐way ANOVA, P<0.01), and hatchling VT whitefish had a significantly different VO 2 compared to 5°C measured at 2, 5 or 8 °C (1‐way ANOVA, P<0.001, Duncan post hoc ). This study demonstrates that variable thermal embryonic incubation produces fewer (increased mortality), smaller embryos that hatch earlier. The plasticity of VO 2 for this stenothermic‐incubating fish species under variable incubation conditions could represent a metabolic cost to fluctuating thermal incubation conditions. Support or Funding Information J.E. and C.A.M. were supported by a MITACS Accelerate grant to D.R.B and J.Y.W. Funding was provided by Bruce Power, Inc. and a Collaborative Research and Development Grant from the Natural Sciences and Engineering Research Council of Canada to J.Y.W., R.G.M., and C.M.S.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".