Size Selective Feeding in Captive and Free Ranging Atlantic Bluefin Tuna
Bibliographic record
Abstract
Abstract We examined size selective feeding in captive and free ranging Atlantic Bluefin Tuna Thunnus thynnus. For the captive study, Bluefin Tuna were maintained in a cylindrical net pen enclosure (30.5 m in diameter; 15.2 m deep) located 32.2 km offshore of Virginia. Tests of prey size selectivity by captive Bluefin Tuna were observed using underwater video. In free ranging Bluefin Tuna, size selection was examined by comparing the sizes of Atlantic Menhaden Brevoortia tyrannus found in stomach contents with the sizes of those collected during the fall purse seine fishery for Atlantic Menhaden off the North Carolina coast. Captive Bluefin Tuna selected larger prey when prey length : predator length ratios (PPRs) were less than 10%; however, size selectivity was not observed when the PPRs exceeded 10%. For free ranging Bluefin Tuna, PPRs were mostly greater than 10% (12.98 ± 0.06% [mean ± SE]), and there were no significant differences in length between Atlantic Menhaden from stomach contents and those from purse seine collections. The minimum and median sizes of Atlantic Menhaden prey increased with increasing predator size; however, the maximum size of Atlantic Menhaden prey did not change, indicating that the smallest Bluefin Tuna sampled could consume the largest Atlantic Menhaden. We conclude that the relatively small size of forage fishes commonly observed in Bluefin Tuna stomachs was likely due to the high abundance of these fishes in the environment rather than to active selection for small prey. Received August 29, 2013; accepted January 14, 2014
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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) | 0.001 | 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".