THE PRESENCE OF SEA LICE ON STEELHEAD TROUT AT A MARINE FARM IN NH WATERS AND THE UTILIZATION OF LUMPFISH AS A BIOLOGICAL DELOUSER
Bibliographic record
Abstract
Sea lice are copepodid ectoparasites that infect fish, and cost salmonid farmers millions of dollars each year in damaged product and mitigation efforts. Conventional treatments can unintentionally impact the ambient environment and lead to the lice developing resistance to the treatments. In recent years, lumpfish (Cyclopterus lumpus) have been utilized successfully to naturally clean sea lice from infected salmonids in European and Atlantic Canadian farms, however this technology has yet to be used in US farms. In New Hampshire coastal waters, New Hampshire Sea Grant and the University of New Hampshire operate an experimental steelhead trout (Oncorhynchus mykiss) farm, AquaFort. To understand seasonal occurrence of lice populations at AquaFort and which lice species are present, steelhead were subsampled weekly for sea lice during farm use throughout 2019-2021. Lice abundance, species present, sex ratio, life stage, and occurrence of gravid females were determined. Lice loads (mean lice per fish) peaked on January 19, 2020, at 3.60 lice per fish, and the dominant species observed was Caligus elongatus (n=930) though some individuals of Caligus curtus were observed (n=9). Female lice made up 74% of the lice population throughout the assessment, and adults made up 87% of all lice observed throughout the assessment. The lice loads of gravid females peaked on February 18, 2021, at 2.20 gravid lice per fish. To understand how lumpfish could mitigate sea lice infestations, small, in situ- experimental cages were stocked with different treatments of steelhead trout (strain), lumpfish (presence, absence), and lumpfish hide designs (kelp, PVC panels). Water temperature, fish survival, lice loads, and lumpfish stomach contents were analyzed throughout two 5-week trials to examine lumpfish impacts on sea lice loads. In both caging trials, hide design affected mean lice loads on trout, with lower lice loads in cages containing kelp hides, and in one trial, lice loads were lower in cages containing lumpfish versus no cleanerfish, however, there was no evidence of sea lice within lumpfish stomachs at the end of each trial. Water temperature and lumpfish size differed between the two trials suggesting that cleanerfish size, hide design, and water temperature are key variables to consider for effective sea lice control. These foundational studies contribute towards developing best practices of lumpfish use for sea lice mitigation on steelhead trout, such as when to implement lumpfish to maximize their welfare and cleaning capabilities. This will ultimately lead towards the goal of increasing the sustainability and production of steelhead trout aquaculture in NH coastal waters.
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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 | 0.001 | 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".