Downstream migration of juvenile pink salmon (Oncorhynchus gorbuscha) in a large Barents Sea river
Bibliographic record
Abstract
The pink salmon (Oncorhynchus gorbuscha, Walbaum 1792) population in the River Teno (Tana in Norwegian, Deatnu in Northern Sámi), located in northernmost Finland, has increased from a few hundred to nearly 200 000 individuals over the past decade, with no signs of slowing population growth. Currently, pink salmon in the River Teno outnumber the populations of native Atlantic salmon (Salmo salar) which have significantly declined since the early 2000s. My thesis aimed to fill knowledge gaps related to the timing of downstream migration of juvenile pink salmon in the River Teno and its largest Finnish tributary, the River Utsjoki. Data on juvenile pink salmon evelopment, migration activity, and feeding behaviour were collected in the River Teno basin from early May to mid-July 2024. The methodology was divided into five components: (1) excavation of redds in the River Teno for estimates of individual development, (2) trap netting of downstream migrating juveniles to establish the onset and duration of the emigration period, (3) beach seining at the river mouth to estimate developments in feeding behaviour, (4) stomach content analysis of collected juveniles to improve knowledge of feeding behaviour, and (5) stable isotope analysis to assess the shift from maternally transferred nutrients to exogenous feeding. The results indicated that the downstream migration of juvenile pink salmon in the River Utsjoki started in early May and continued for about a month, tapering off in early June. This pattern was also observed in the River Teno. The number of migrants increased rapidly with the spring flood, and peak catches coincided with peaks in flow rate. Unlike previous research that found significant temperature impacts on migration activity, no clear relationship between temperature and migration activity was observed. Larger juveniles showed a greater reliance on freshwater prey, as evidenced by changes in isotope ratios and increased stomach contents. This thesis stresses the rapid adaptation of juvenile pink salmon to the Barents Sea region, contributing to our understanding of their life history and ecological impact within North Atlantic ecosystems.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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; both teacher heads agree on what is shown here.
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".