The Ecology of Juvenile Salmon in the Northeast Pacific Ocean: Regional Comparisons
Bibliographic record
Abstract
Abstract.—We compared epipelagic fish assemblages associated with juvenile (ocean-age 0) Pacific salmon Oncorhynchus spp. from neritic waters of the California Current and Alaska Current regions in the spring–summer and summer–fall periods of 2000–2004. Catches originated from rope trawl surveys conducted between latitudes 37°N and 60°N and spanned more than 1,100 km in the coastal and inshore habitats of each region. Catch data were used from the epipelagic sampling of waters from near surface to depths of about 18 m, primarily over the continental shelf. Catch composition, frequency of occurrence, and density were evaluated between regions and habitats for day sampling. Diel (night and day) catch comparisons were also made at a few localities in each region. In day catches from both regions, a total of 1.69 million fish and squid representing 52 fish families and 118 fish species were sampled from 2,390 trawl hauls. Ninety-seven percent of the daytime catch was composed of 11 fish families and squid in coastal and inshore habitats of each region: clupeids dominated catches in the California Current (72% and 76% of catch, respectively), and salmonids dominated catches in the Alaska Current (46% and 62% of catch, respectively). Juveniles comprised 81–99% of salmon sampled in both coastal and inshore habitats of each region. Frequencies of occurrence were highest for juvenile salmon in both regions, but average densities were highest for Pacific herring Clupea pallasii and Pacific sardine Sardinops sagax in the California Current region. Cluster analyses revealed distinct geographic breakpoints in coastal species assemblages off central Vancouver Island and in inshore species assemblages in southeastern Alaska. Species were found to cluster into six groups from coastal localities and four groups from inshore localities. Indicator species analysis and nonmetric multidimensional scaling revealed that most species of juvenile salmonids were located in northern localities. Although juvenile salmon had the most uniform distribution of any species group, their densities relative to associated species were dramatically lower in the California Current, suggesting a higher degree of interactions between juvenile salmon and other species in this region. Diel comparisons in both regions indicated substantially higher catches at night, particularly of clupeids, osmerids, and gadids. Salmonids were a relatively minor component of the night catch in both regions due to dramatic diel shifts in community structure. Additional study of diel interactions of juvenile salmon and associated species is needed to quantify habitat utilization dynamics in marine ecosystems.
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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 | 0.001 |
| 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".