Stable isotope analysis of Rivers Inlet sockeye salmon (Oncorhynchus nerka) : investigating the contribution of environmental conditions in the high seas to British Columbia population declines.
Why this work is in the frame
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Bibliographic record
Abstract
Sockeye salmon (Oncorhynchus nerka) populations in BC have undergone varying degrees of decline coinciding with a shift to a warmer phase of the Pacific Decadal Oscillation (PDO) in 1977. The PDO, and other climate cycles, have been shown to significantly affect the physical and biological characteristics of the North East Pacific Ocean. Changes in ocean productivity have implications for pelagic food webs and may cause shifts in the abundance of potential prey for sockeye salmon, impacting their long-term production patterns. We investigated the coupling of ocean conditions and population fluctuations using Rivers Inlet as a case study, a system that suffered probably the most catastrophic sockeye stock collapse in BC history. Stable isotope analysis was used to access information on ocean conditions stored in the carbon and nitrogen isotope ratios of archived sockeye scales for the period 1915-2013. Our results indicated that Rivers Inlet sockeye salmon experienced highly variable open ocean conditions during this period. Both decadal scale shifts in North Pacific climate (e.g., PDO) and interannual scale shifts in climate (e.g., El Niño/La Niña events) were reflected in the physical and biological environment of the offshore Gulf of Alaska. Positive phases of the PDO and El Niño events were associated with a warmer and less productive ocean, while negative phases of the PDO and La Niña events were associated with a colder and more productive ocean. Moreover, the carbon and nitrogen stable isotope time-series indicated that the foraging habits of Rivers Inlet sockeye salmon were affected by these shifts of North Pacific climate. A lengthening (shortening) of the food web was associated to warm (cold) and less productive (more productive) periods. In addition, the isotope data also supports Rivers Inlet sockeye salmon shifting diet depending upon prey availability. We concluded that a combination of the two factors was responsible for the changes in the feeding ecology of Rivers Inlet sockeye salmon during the period 1915-2013. Such variation in the feeding ecology of Rivers Inlet sockeye salmon could potentially have a negative effect in the overall survival rates of sockeye salmon.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.004 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 it