Lake Ontario Alewife, Alosa pseudoharengus, maturation and reproduction dynamics
Bibliographic record
Abstract
Since their introduction in Lake Ontario, alewife (Alosa pseudoharengus) have dominated the forage fish community, making them the primary food source for the lake’s economically valuable sport fish populations. Therefore, alewife population dynamics can impact fishery success and management. Recently observed declines in alewife abundance and year class strength variability further increase the need to better understand alewife reproduction. The objectives of this study were to quantify maturation and reproductive dynamics of Lake Ontario alewife by 1) determining if alewife display determinate or indeterminate fecundity, 2) determining if age 2 alewife could be considered part of the spawning stock, and 3) assessing reproductive potential across alewife ages 2 to 6. We collected alewife from various locations in Lake Ontario from October 2017 to October 2018 and measured gonadosomatic index, condition factor, gonad development, spawning potential, batch fecundity, and embryo survival data. Evidence of a prolonged spawning season and the presence of multiple batches of advanced oocytes in the ovaries of alewife suggest this species display indeterminate fecundity (i.e., can spawn multiple batches of eggs in a single spawning season). Spawning potential (observed spawning and or the presence of mature gonads) was observed in 63.9% of age 2 females and 90.4% of age 2 males captured in June and July, indicating age 2 alewife should be considered part of the spawning stock. This was confirmed by the successful survival of embryos of age 2 parents. When comparing embryo survival data among all ages, older females displayed higher embryo survival, and our beta regression model suggested female age best explained observed. In addition, alewife older than age 2 appeared to have a higher proportion of indeterminate spawners, further suggesting older alewife have increased reproductive output vs younger fish. However, the lack of variation in relative batch fecundity among ages suggest other variables, such as size may better explain this variability.
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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".