Synchronized hatch and its ecological significance in rainbow smelt Osmerus mordax in St. Mary's Bay, Newfoundland
Bibliographic record
Abstract
Early life history stages in most marine animals are subject to high mortality through predation, starvation, and dispersal. Accordingly, the potential exists for the selection of behavioral mechanisms that reduce mortality. We examined the ecological significance of synchronization in hatch and the initiation of larval drift in rainbow smelt, Osmerus mordax, populations in St. Mary's Bay, Newfoundland. Larval abundances from six 24‐h ring net surveys (2‐h intervals) in Colinet and Salmonier Rivers during 2002/2003 suggest synchronized hatch following dusk (~2200 h). Monitoring of egg hatching in situ confirmed synchrony was at hatch and notemergence. Larval abundance showed no relationship with temperature or flow rates, and the consistency in hatch pattern suggested a light/dark cue. In experimental manipulations in which eggs were exposed to light and dark conditions for 2‐h periods, hatch percentages were up to five times higher (p < 0.005) in dark treatments. We hypothesized that the linkage of hatch to low light levels represents a mechanism to avoid elevated larval predation in daylight conditions. Egg predation determined from predator gut content analysis suggested that extreme predation risk from small (<20 cm) salmonids peaked during the day, prior to dusk, and was lowest during night (2200–0400 h). Microcosm experiments demonstrated that newly hatched larvae exposed to predators in dark conditionsdid not change in number, but mortality averaged 60% in light conditions. Our results suggest that predation pressure during the early life history of aquatic organisms might play a strong role in the optimization of aquatic life histories.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 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".