Tilapias and Indigenous Fish Biodiversity in Sri Lanka
Bibliographic record
Abstract
Some species of tilapias are now found worldwide in natural and artificial habitats in the tropics and sub tropics. Claims have been made from time to time that tilapias have displaced indigenous fishes and damaged fish culture. In this paper an attempt is made to examine some of these statements and evaluate whether there is a basis for such claims. In Sri Lanka, introduced tilapias are found mainly in manmade reservoirs and still there are no records of established populations of exotic tilapias in-the river systems in the country where indigenous and endemic freshwater fish species are found. The major threats to freshwater fish biodiversity include habitat degradation and overexploitation for the ornamental fish trade. In Sri Lanka, introduction of tilapias to lacustrine waters has been beneficial in terms of contributing to fish production. Tilapias have been in natural and artificial habitats throughout the tropics and the sub-tropics for over 50 years. Considering the immense number of introductions of tilapias into individual habitats in many parts of the tropics and subtropics, surprisingly few substantiated cases of their damaging indigenous fish communities have so far been recorded. Some of these claims of cases of presumed or real damage to local fish stocks are ambiguous or ware unsubstantiated speculations. To expect absolutely no negative effects at all on the indigenous fishes by tilapias is unrealistic. On the other hand substantial quantities of tilapias are now harvested from reservoirs or raised in culture where no such enterprises existed earlier.
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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 | 0.001 | 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 | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".