Seasonal variation in the diet of juvenile lake sturgeon,<i>Acipenser fulvescens</i>, Rafinesque, 1817, in the Winnipeg River, Manitoba, Canada
Bibliographic record
Abstract
The lake sturgeon, Acipenser fulvescens, is a threatened species across most of its range. To understand any potential shifts in diet across season or habitat, stomach contents were examined from juvenile lake sturgeon caught in the Winnipeg River, Manitoba, Canada. This information will aid in assessment of environmental impacts and conservation initiatives for this threatened species. From 2006 to 2008 gut contents were collected from juvenile lake sturgeon using a non-lethal gastric lavage methodology. Juvenile lake sturgeon were sampled from four discrete deep water habitat types (13.7–27.4 m depths), during the months of May, June, July and October. In total, 13 066 prey items belonging to 14 prey groups were collected from 345 juvenile lake sturgeon (251–835 mm TL). Overall, juvenile lake sturgeon consumed a low diversity of organisms; insect larvae from three invertebrate orders, Trichoptera, Diptera and Ephemeroptera, accounted for 97.4% of the total numeric abundance of prey items recovered. A relationship between size of juvenile lake sturgeon and prey quantity or type was not observed. Diet of juvenile lake sturgeon varied in relation to season, with Diptera (77.6%) being the most abundant prey in May, Trichoptera the most abundant in June (n = 3,056, 60.4%) and July (n = 2,055, 52.6%). During October, 96% of stomachs examined were empty. In terms of habitat type, the standardized abundance of invertebrate prey items was highest in deep water habitats characterized by medium water velocity (depths > 13.7 m) and coarse substrate (particle sizes > 0.063 mm) in May and June when compared to deep water habitats characterized by low water velocity (<0.2 m.s−1) and fine substrate (particle sizes < 0.063 mm). However, in July, the opposite was observed and prey abundance in juvenile lake sturgeon stomachs decreased with increasing particle size. Results suggest a high degree of dietary overlap among juvenile lake sturgeon from multiple size/age classes occupying deep-water habitats of the Winnipeg River.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| 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 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".