Salmon lice from aquaculture reduce marine survival of Atlantic salmon
Bibliographic record
Abstract
Salmon lice from marine salmon aquaculture have been shown to impact the survival of wild salmon migrating through aquaculture areas, but quantifying the level of impact has proven difficult. This difficulty has led to the use of randomised control trials. These trials comprise paired releases of typically hatchery-origin groups of untreated salmon smolts and those with a prophylactic treatment against salmon lice, to provide an estimate of the level of increased marine survival due to the treatment, as a proxy to inform such effects on wild salmon. Here, we use data from previously published Irish studies together with 15 unpublished paired release trials standardised using actual recapture data (raw data) to examine differences in survival. Results from meta-analysis of 43 paired releases spanning the period 2001 to 2019 show a significant treatment effect against lice with a risk ratio of 1.22, equating to 18% less return of untreated adult hatchery salmon. Meta-regression further demonstrated that the risk increased with lice infestation pressure from salmon farms. Infestation pressure was also significantly associated with declining return rates in both the treated and untreated groups, corroborating earlier findings that the chemical treatment against lice may not completely shield the post-smolt salmon against the virulent effect of lice. Overall, these results indicate that the effect of salmon lice is larger than the average effects across years reported in earlier randomised control trial studies. Policy implications. The meta-analysis points to salmon lice from salmon aquaculture as a mechanistic threat to wild Atlantic salmon. It emphasises the need for the sector to have effective sea lice management such that there is no increase in lice-induced mortality of wild salmonids as per the international goal of the North Atlantic Salmon Conservation Organisation. The findings are also relevant for the conservation goals set for Atlantic salmon under the EU Habitats Directive in river stocks potentially susceptible to this pressure.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.012 | 0.020 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.003 | 0.024 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 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".