Bibliographic record
Abstract
The main theoretical problem in marine fisheries research is the uncertainty surrounding recruitment. The relationship between the number of fertile eggs and the generation to which they give rise, normally called the >stock-recruitment relationship>, is a problem which embraces a wide variety of aspects, all of them included in marine ecology. In this work, the biological and ecological basics of the pre-recruit stages are dealt with first. There is a general negative exponential relationship between temperature and age of hatching in the planktonic eggs of fish; those which do not float hatch at an older age. There is also a negative exponential relationship on the one hand between the time of hatching and first feeding, and on the other with temperature. The importance of starvation and predation as factors discussed. Cannibalism does not seem to be a significant factor in compensatory mortality except in Peruvian anchovettas. Hypotheses concerning fluctuations in recruitment are reviewed. On short time scales, they are explanations of the success of feeding by pre-recruits due to hydrographic and meteorological causes. On longer time scales, they related variations in recruitment to geophysical, astronomical and climatic factors. Parametric models of the stock-recruitment (S/R) relationship are examined. The best way to introduce environmental factors is by linear regression. Ussing this regression, the amount of variance accounted for by the environmental factors can be studied. Contrary to what is generally accepted, the real instrinsic population parameter is density-independent, while the density-dependent will always be related to the environmental factors which determine the food density. The use of non-parametric models simplifies the study of S/R. All of them have the drawback that they ignore the ecological aspects of year class success. The physical factors (salinity, temperature, wind, etc.) are really >predictors> of the pre-recruit survival values. The geophysical and astronomical factors (nodal tides, polar motion, length of day, etc.) are predictors of the ecological conditions in a particular area. Possible consequences of the risk of greenhouse warming are examined. Alternation of species is a typical phenomenon in the pelagic environment. The principle cause is due to the adults of the dominant species feeding on the eggs and larvae of the secondary species. If the biomass of the dominant species is strongly reduced, by at least half, the secondary species eventually becomes dominant. A massive increase in pelagic species by predation on their eggs and larvae. The alternation of demersal species is less common. The classical collapse of a fishery begins with an enormous recruitment, low recruitment follows, biomass is drastically reduced, and the collapse is maintained if the species becomes sub-dominant. The magnitude of recruitment depends on the ecological conditions in which the pre-recruits develop, but also on the energy stored by the parents. Life-history strategies differ; in pelagic species growth is initially rapid, and variations in energy consumption are reflected in fecundity, but in demersal species variations in energy comsumption influence growth rather than fecundity. In semiparous species, post-spawning survival is sacrified.Different patterns of evolution of the S/R relationship in fish are described. The hypothesis of Shepherd & Cushing (1990) concerning the influence of stochastic processes on recruitment variability is only supported in a minority of the S/R patterns studied.
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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 | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.004 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.003 |
| Bibliometrics | 0.004 | 0.003 |
| Science and technology studies | 0.002 | 0.003 |
| Scholarly communication | 0.005 | 0.009 |
| Open science | 0.005 | 0.005 |
| Research integrity | 0.008 | 0.004 |
| Insufficient payload (model declined to judge) | 0.991 | 0.994 |
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; the direct Gemma label and the distilled Codex classifier agree on what is shown here.
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".