Spawning Success of Farmed Atlantic Cod (Gadus morhua): Effects of Photoperiod on Gonad Development in Sea Cages in Eastern Canada IES CM 2009
Bibliographic record
Abstract
No abstracts are to be cited without prior reference to the author.The use of extended daylength to suppress sexual maturation of Atlantic salmon (Salmo salar) in sea cages has been successfully adopted by fish farmers. The same methods when applied to Atlantic cod (Gadus morhua) however, have been disappointing as gonadal development of cod in sea cages exposed to extended daylength is seasonally delayed but not arrested. Results of a set of photoperiod trials using 20 h and 24 h light in sea cages indicated that between 87-100% of fish achieved sexual maturation. The use of lights did however delay sexual maturation such that females were gravid for several months through summer. Grower diets currently used in Atlantic Canada have led to enlarged livers and this may also have played a role in disrupting normal gonadal development and affected gamete quality. Hepatosomatic indices were also well above those of wild cod. In Canada, the fate of drifting eggs from sea cages has not been evaluated. We discuss some of the biological and environmental conditions in the Bay of Fundy near cod cage sites and make inferences about the potential survivorship of embryo “escapes’. The extent of Atlantic cod farming in Canada is in a preliminary phase with limited concentration in the Bay of Fundy and coastal Newfoundland with no escaped juvenile or adult cod reported to date.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 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".