Feeding Ecology of Juvenile Lake Sturgeon in the St. Lawrence River System
Bibliographic record
Abstract
Abstract We examined the diet of juvenile lake sturgeon Acipenser fulvescens at five sites in the St. Lawrence River, including two sites in major tributaries (Des Prairies and L'Assomption rivers), two main‐stem sites located upstream (Verchères and Sorel‐Berthier islands), and one site located downstream in the estuarine transition zone (ETZ). The benthic fauna was sampled at all sites except in the ETZ. The diets of juvenile lake sturgeon were highly diverse. Of the 74 invertebrate prey taxa identified, approximately 50 occurred in more than 5% of the stomach contents. Most of these prey taxa were of small size. In the three sites where the same sampling strategy and techniques were used, diet varied significantly with sampling site and month. In addition, diet varied significantly with fish length but independently of site and month. Lake sturgeon from the Verchères Islands exhibited the highest diet diversity, and fish situated in the ETZ exhibited the lowest. Except for one of the five sites (L'Assomption River), diet was dominated by amphipods. Chironomids predominated at L'Assomption River and were the second most numerous at the Verchères Islands, Sorel‐Berthier Islands, and Montmagny sites. Other important prey were oligochaetes, ephemeropteran nymphs, trichopteran larvae, mollusks, and fish eggs. The benthos composition differed among sites. Positive values for Ivlev's electivity index were found for malacostracans and ephemeropteran nymphs at all four upstream sites and for dipteran larvae at one upstream site; mollusks were generally negatively selected at one upstream site. At the three sites where the same sampling strategy was used, food preference differed as a function of site and month. Within some site × month combinations, preference also varied with fish length. Our results (1) confirm that juvenile lake sturgeon are generalists and opportunistic benthic feeders, (2) reveal that diet composition is only partly determined by benthos availability, and (3) suggest that there is positive selection for drifting prey. Within the study area, lake sturgeon aggregate locally, but the presence of juveniles in these specific areas cannot be fully explained by their food habits.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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".