Selective predisposition of Nile tilapia (<i>Oreochromis niloticus</i> L.) to bacterial and parasitic infection- evidence from the crater lakes Babogaya and Hora-Arsedi, Ethiopia
Bibliographic record
Abstract
Mass mortalities of fish sporadically occur throughout the globe and often caused by single or multiple factors posing difficulties on the search for plausible explanations. Following the selective mass mortality of Oreochromis niloticus in two of the Bishoftu Crater Lakes: Babogaya, and Hora-Arsedi between April and May of 2013, we carried out a snapshot survey on the limnology of Lakes Babogaya and Hora-Arsedi including the histopathological and bacteriological examinations of O. niloticus fish. Complete mixing of the lake water and the subsequent anoxic condition was primarily hypothesized as the likely cause. However, vertical, profile of water temperatures and dissolved oxygen concentrations revealed that both lakes were stratified and the epilimnion was well oxygenated (> 8.9 mg L -1 ). All key water quality parameters were within the optimum range for O. niloticus culture except ammonia which was well above the lethal level (2.1 mg L -1 ) in Babogaya and stressive sublethal level of 0.1mg L -1 in Hora-Arsedi. Live fish samples showed clinical symptoms such as caudal skin lesion and injured gills. Postmortem examinations revealed hemorrhagic shock, liver and kidney damage with Aeromonas sp. and parasitic infections detected. Therefore we concluded that direct ammonia toxicity have caused the mortalities in Lake Babogaya, whilst extended sublethal ammonia exposure with subsequent stress and gill damage predisposed the fish to bacterial and parasitic infection that led to mass mortalities in Lake Hora-Arsedi.
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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 | 0.000 | 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".