Seasonal variation in testes size and density detected in belugas (Delphinapterus leucas) using ultrasonography
Bibliographic record
Abstract
Belugas are thought to exhibit seasonal variation in testes size, but a temporal gap in postmortem sampling of wild belugas has precluded a description of the occurrence or the extent of this seasonal variation. This study aimed to utilize longitudinal monitoring of belugas in aquaria with known siring histories to assess seasonal variation in testes size, and its association with circulating testosterone concentration and testicular tissue density. Testes volume was estimated using linear measurements obtained via ultrasonography. Testicular tissue density was assessed by measuring the pixel intensity (PI) of ultrasound images of the testis. Five adult males, including 4 proven sires, were monitored for at least 1 continuous year; 2 of the males were monitored for > 2 years. A total of 154 ultrasound examinations (including 71 suitable for PI measurements) and 119 blood samples were available for analysis. Significant seasonal variation in testes volume, circulating testosterone concentration, and testicular PI were observed, with peak activity occurring between January and April. Seasonality of testicular volume was best described by a cubic function, while seasonal variations in testosterone and PI were best described by quadratic functions. Individuals differed significantly in both testes size and rate of change. On average, testes size increased by 60% from minimum to maximum values. These results are consistent with observations of reproductive seasonality both in the wild and in aquaria, and suggest a relatively low demand for sperm in this species that is consistent with their classification as induced ovulators.
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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 | 0.001 |
| 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) | 0.000 | 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".