Relationships among vertically structured <i>in situ</i> measures of turbulence, larval fish abundance and feeding success and copepods on Western Bank, Scotian Shelf
Bibliographic record
Abstract
Using vertically stratified data of the abundance of silver hake ( Merluccius bilinearis ) larvae and concentrations of copepods collected in the field, we examine relationships among the vertical distribution of larval fish, their potential prey, feeding success and water column turbulence. Water column turbulence and associated stratification parameters were estimated from: (i) in situ measures of turbulent kinetic energy dissipation ( ɛ ) provided by an EPSONDE profiler; (ii) in situ wind speed; (iii) the Richardson number ( Ri ); and (iv) the buoyancy frequency ( N 2 ). Small (< 5 mm total length) silver hake were more abundant in the least turbulent waters (i.e. at a minimum in the rate of dissipation of turbulent kinetic energy, ɛ < 10 –7 W kg −1 ; Ri > 0.25; N 2 > 0.001 (rad s –1 ) 2 ). Partial correlations amongst ɛ , N 2 and small hake larvae were significant only for N 2 . The abundance of larger (> 5 mm total length) hake larvae was positively correlated with depth and was not associated with either ɛ or N 2 . Vertical distributions of three potential prey (classified by stage) were variable. Early stage copepodids were positively correlated with N 2 and negatively correlated with ɛ . We found no evidence of diel distribution patterns for small (< 5 mm total length) hake larvae or for any of the developmental stages of the copepods examined. Neither estimate of water column turbulence inferred from wind speed nor from Ri was meaningfully related to in situ estimates of ɛ or to larval fish abundance. Feeding success, measured either as prey items (gut) –1 , average prey length, or total prey volume (gut) –1 , was not related to predicted encounter rates between days. However, the average prey length (gut) –1 was significantly ( P < 0.01) related to water column turbulence. These conflicting results suggest that the relationship between larval feeding and the environment is more complicated than assumed. We conclude that without substantial high resolution in situ examination of the relationship between the vertical distributions of turbulence, larvae and their prey, the growing acceptance in the secondary literature that turbulence has a positive and biologically meaningful effect on trophic interactions between fish and their zooplankton prey (a generalization based largely on modelling and laboratory experiments) is premature.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| 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 teacher head, 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".