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Trombetta E, Jakubiak S, Kutkova S, Lipschutz D, O’Hare A, Enright JA. A modeling study of the impact of treatment policies on the evolution of resistance in sea lice on salmon farms. PLoS One 2023; 18:e0294708. [PMID: 38019751 PMCID: PMC10686416 DOI: 10.1371/journal.pone.0294708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/08/2023] [Indexed: 12/01/2023] Open
Abstract
Salmonid aquaculture is an important source of nutritious food with more than 2 million tonnes of fish produced each year (Food and Agriculture Organisation of the United Nations, 2019). In most salmon producing countries, sea lice represent a major barrier to the sustainability of salmonid aquaculture. This issue is exacerbated by widespread resistance to chemical treatments on both sides of the Atlantic. Regulation for sea lice management mostly involves reporting lice counts and treatment thresholds, which depending on interpretation may encourage preemptive treatments. We have developed a stochastic simulation model of sea lice infestation including the lice life-cycle, genetic resistance to treatment, a wildlife reservoir, salmon growth and stocking practices in the context of infestation, and coordination of treatment between farms. Farms report infestation levels to a central organisation, and may then cooperate or not when coordinated treatment is triggered. Treatment practice then impacts the level of resistance in the surrounding sea lice population. Our simulation finds that treatment drives selection for resistance and coordination between managers is key. We also find that position in the hydrologically-derived network of farms can impact individual farm infestation levels and the topology of this network can impact overall infestation and resistance. We show how coordination and triggering of treatment alongside varying hydrological topology of farm connections affects the evolution of lice resistance, and thus optimise salmon quality within socio-economic and environmental constraints. Network topology drives infestation levels in cages, treatments, and hence treatment-driven resistance. Thus farmer behaviour may be highly dependent on hydrologically position and local level of infestation.
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Affiliation(s)
- Enrico Trombetta
- School of Computing Science, University of Glasgow, Glasgow, United Kingdom
| | - Sara Jakubiak
- School of Computing Science, University of Glasgow, Glasgow, United Kingdom
| | - Sara Kutkova
- School of Computing Science, University of Glasgow, Glasgow, United Kingdom
| | - Debby Lipschutz
- Usher Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Anthony O’Hare
- Computing Science and Mathematics, University of Stirling, Stirling, United Kingdom
| | - Jessica A. Enright
- School of Computing Science, University of Glasgow, Glasgow, United Kingdom
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2
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Giordano R, Weber EP, Mitacek R, Flores A, Ledesma A, De AK, Herman TK, Soto-Adames FN, Nguyen MQ, Hill CB, Hartman GL. Patterns of asexual reproduction of the soybean aphid, Aphis glycines (Matsumura), with and without the secondary symbionts Wolbachia and Arsenophonus, on susceptible and resistant soybean genotypes. Front Microbiol 2023; 14:1209595. [PMID: 37720159 PMCID: PMC10501154 DOI: 10.3389/fmicb.2023.1209595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/25/2023] [Indexed: 09/19/2023] Open
Abstract
Plant breeding is used to develop crops with host resistance to aphids, however, virulent biotypes often develop that overcome host resistance genes. We tested whether the symbionts, Arsenophonus (A) and Wolbachia (W), affect virulence and fecundity in soybean aphid biotypes Bt1 and Bt3 cultured on whole plants and detached leaves of three resistant, Rag1, Rag2 and Rag1 + 2, and one susceptible, W82, soybean genotypes. Whole plants and individual aphid experiments of A. glycines with and without Arsenophonus and Wolbachia did not show differences in overall fecundity. Differences were observed in peak fecundity, first day of deposition, and day of maximum nymph deposition of individual aphids on detached leaves. Bt3 had higher fecundity than Bt1 on detached leaves of all plant genotypes regardless of bacterial profile. Symbionts did not affect peak fecundity of Bt1 but increased it in Bt3 (A+W+) and all Bt3 strains began to deposit nymphs earlier than the Bt1 (A+W-). Arsenophonus in Bt1 delayed the first day of nymph deposition in comparison to aposymbiotic Bt1 except when reared on Rag1 + 2. For the Bt1 and Bt3 strains, symbionts did not result in a significant difference in the day they deposited the maximum number of nymphs nor was there a difference in survival or variability in number of nymphs deposited. Variability of number of aphids deposited was higher in aphids feeding on resistant plant genotypes. The impact of Arsenophonus on soybean aphid patterns of fecundity was dependent on the aphid biotype and plant genotype. Wolbachia alone had no detectable impact but may have contributed to the increased fecundity of Bt3 (A+W+). An individual based model, using data from the detached leaves experiment and with intraspecific competition removed, found patterns similar to those observed in the greenhouse and growth chamber experiments including a significant interaction between soybean genotype and aphid strain. Combining individual data with the individual based model of population growth isolated the impact of fecundity and host resistance from intraspecific competition and host health. Changes to patterns of fecundity, influenced by the composition and concentration of symbionts, may contribute to competitive interactions among aphid genotypes and influence selection on virulent aphid populations.
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Affiliation(s)
- Rosanna Giordano
- Institute of Environment, Florida International University, Miami, FL, United States
- Puerto Rico Science Technology and Research Trust, San Juan, Puerto Rico
| | - Everett P. Weber
- Office of Institutional Research, Dartmouth College, Hanover, NH, United States
| | - Ryan Mitacek
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Alejandra Flores
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Alonso Ledesma
- College of Agricultural, Consumer and Environmental Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Arun K. De
- Animal Sciences Division, ICAR-Central Island Agricultural Research Institute, Port Blair, India
| | | | - Felipe N. Soto-Adames
- Division of Plant Industry, Florida Department of Agriculture and Consumer Services, Gainesville, FL, United States
| | - Minh Q. Nguyen
- Neochromosome, Inc., Long Island City, NY, United States
| | - Curtis B. Hill
- Neochromosome, Inc., Long Island City, NY, United States
| | - Glen L. Hartman
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
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3
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Robinson NA, Robledo D, Sveen L, Daniels RR, Krasnov A, Coates A, Jin YH, Barrett LT, Lillehammer M, Kettunen AH, Phillips BL, Dempster T, Doeschl‐Wilson A, Samsing F, Difford G, Salisbury S, Gjerde B, Haugen J, Burgerhout E, Dagnachew BS, Kurian D, Fast MD, Rye M, Salazar M, Bron JE, Monaghan SJ, Jacq C, Birkett M, Browman HI, Skiftesvik AB, Fields DM, Selander E, Bui S, Sonesson A, Skugor S, Østbye TK, Houston RD. Applying genetic technologies to combat infectious diseases in aquaculture. REVIEWS IN AQUACULTURE 2023; 15:491-535. [PMID: 38504717 PMCID: PMC10946606 DOI: 10.1111/raq.12733] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 07/24/2022] [Accepted: 08/16/2022] [Indexed: 03/21/2024]
Abstract
Disease and parasitism cause major welfare, environmental and economic concerns for global aquaculture. In this review, we examine the status and potential of technologies that exploit genetic variation in host resistance to tackle this problem. We argue that there is an urgent need to improve understanding of the genetic mechanisms involved, leading to the development of tools that can be applied to boost host resistance and reduce the disease burden. We draw on two pressing global disease problems as case studies-sea lice infestations in salmonids and white spot syndrome in shrimp. We review how the latest genetic technologies can be capitalised upon to determine the mechanisms underlying inter- and intra-species variation in pathogen/parasite resistance, and how the derived knowledge could be applied to boost disease resistance using selective breeding, gene editing and/or with targeted feed treatments and vaccines. Gene editing brings novel opportunities, but also implementation and dissemination challenges, and necessitates new protocols to integrate the technology into aquaculture breeding programmes. There is also an ongoing need to minimise risks of disease agents evolving to overcome genetic improvements to host resistance, and insights from epidemiological and evolutionary models of pathogen infestation in wild and cultured host populations are explored. Ethical issues around the different approaches for achieving genetic resistance are discussed. Application of genetic technologies and approaches has potential to improve fundamental knowledge of mechanisms affecting genetic resistance and provide effective pathways for implementation that could lead to more resistant aquaculture stocks, transforming global aquaculture.
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Affiliation(s)
- Nicholas A. Robinson
- Nofima ASTromsøNorway
- Sustainable Aquaculture Laboratory—Temperate and Tropical (SALTT)School of BioSciences, The University of MelbourneMelbourneVictoriaAustralia
| | - Diego Robledo
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesThe University of EdinburghEdinburghUK
| | | | - Rose Ruiz Daniels
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesThe University of EdinburghEdinburghUK
| | | | - Andrew Coates
- Sustainable Aquaculture Laboratory—Temperate and Tropical (SALTT)School of BioSciences, The University of MelbourneMelbourneVictoriaAustralia
| | - Ye Hwa Jin
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesThe University of EdinburghEdinburghUK
| | - Luke T. Barrett
- Sustainable Aquaculture Laboratory—Temperate and Tropical (SALTT)School of BioSciences, The University of MelbourneMelbourneVictoriaAustralia
- Institute of Marine Research, Matre Research StationMatredalNorway
| | | | | | - Ben L. Phillips
- Sustainable Aquaculture Laboratory—Temperate and Tropical (SALTT)School of BioSciences, The University of MelbourneMelbourneVictoriaAustralia
| | - Tim Dempster
- Sustainable Aquaculture Laboratory—Temperate and Tropical (SALTT)School of BioSciences, The University of MelbourneMelbourneVictoriaAustralia
| | - Andrea Doeschl‐Wilson
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesThe University of EdinburghEdinburghUK
| | - Francisca Samsing
- Sydney School of Veterinary ScienceThe University of SydneyCamdenAustralia
| | | | - Sarah Salisbury
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesThe University of EdinburghEdinburghUK
| | | | | | | | | | - Dominic Kurian
- The Roslin Institute and Royal (Dick) School of Veterinary StudiesThe University of EdinburghEdinburghUK
| | - Mark D. Fast
- Atlantic Veterinary CollegeThe University of Prince Edward IslandCharlottetownPrince Edward IslandCanada
| | | | | | - James E. Bron
- Institute of AquacultureUniversity of StirlingStirlingScotlandUK
| | - Sean J. Monaghan
- Institute of AquacultureUniversity of StirlingStirlingScotlandUK
| | - Celeste Jacq
- Blue Analytics, Kong Christian Frederiks Plass 3BergenNorway
| | | | - Howard I. Browman
- Institute of Marine Research, Austevoll Research Station, Ecosystem Acoustics GroupTromsøNorway
| | - Anne Berit Skiftesvik
- Institute of Marine Research, Austevoll Research Station, Ecosystem Acoustics GroupTromsøNorway
| | | | - Erik Selander
- Department of Marine SciencesUniversity of GothenburgGothenburgSweden
| | - Samantha Bui
- Institute of Marine Research, Matre Research StationMatredalNorway
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Coates A, Johnsen IA, Dempster T, Phillips BL. Parasite management in aquaculture exerts selection on salmon louse behaviour. Evol Appl 2021; 14:2025-2038. [PMID: 34429746 PMCID: PMC8372093 DOI: 10.1111/eva.13255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 04/18/2021] [Accepted: 05/12/2021] [Indexed: 11/28/2022] Open
Abstract
The evolution of pest resistance to management strategies is a major challenge for farmed systems. Mitigating the effects of pest adaptation requires identifying the selective pressures imposed by these strategies. In Atlantic salmon (Salmo salar) aquaculture, barriers are used to prevent salmon louse (Lepeophtheirus salmonis) larvae (copepodids) from entering salmon cages. These barriers are effective against shallow-swimming copepodids, but those swimming deeper can pass underneath and infest salmon. Laboratory experiments suggest that depth regulation in copepodids is a variable behavioural trait with a genetic basis. We used biological-hydrodynamic dispersal models to assess how this trait variation alters the dispersion of lice through the ocean environment and into farms. The dispersal of copepodids with 3 behavioural phenotypes (deep, mean or shallow) was modelled over winter-spring and spring-summer periods in a Norwegian fjord system with intensive aquaculture. The infestation pressure of each phenotype on barrier cages was estimated from their modelled depth distributions: copepodids deeper than 10 m were predicted to successfully pass underneath barriers. The deep phenotype was the most abundant below 10 m and reached infestation pressures 3 times higher than that of the mean phenotype. In contrast, the shallow phenotype infestation pressure reached less than half that of the mean phenotype. These differences in relative fitness indicate that barriers can impose strong directional selection on the swimming behaviour of copepodids. The strength of this selection varied seasonally and geographically, with selection for the deep phenotype stronger in winter-spring and at coastal locations than in spring-summer and within fjords. These findings can be applied across farms to slow louse adaptation, by limiting barriers during situations of strong selection, although this must be balanced against trade-offs to short-term efficacy. More broadly, our study highlights new ways in which dispersal models can address evolutionary questions crucial for sustainable parasite management in aquaculture.
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Affiliation(s)
- Andrew Coates
- Sustainable Aquaculture Laboratory – Temperate and Tropical (SALTT)School of BioSciencesUniversity of MelbourneParkvilleVic.Australia
- Spatial Ecology and Evolution Lab (SPEEL)School of BioSciencesUniversity of MelbourneParkvilleVic.Australia
| | | | - Tim Dempster
- Sustainable Aquaculture Laboratory – Temperate and Tropical (SALTT)School of BioSciencesUniversity of MelbourneParkvilleVic.Australia
| | - Ben L. Phillips
- Spatial Ecology and Evolution Lab (SPEEL)School of BioSciencesUniversity of MelbourneParkvilleVic.Australia
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5
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Hamre LA, Oldham T, Oppedal F, Nilsen F, Glover KA. The potential for cleaner fish-driven evolution in the salmon louse Lepeophtheirus salmonis: Genetic or environmental control of pigmentation? Ecol Evol 2021; 11:7865-7878. [PMID: 34188857 PMCID: PMC8216962 DOI: 10.1002/ece3.7618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 04/08/2021] [Indexed: 11/25/2022] Open
Abstract
The parasitic salmon louse represents one of the biggest challenges to environmentally sustainable salmonid aquaculture across the globe. This species also displays a high evolutionary potential, as demonstrated by its rapid development of resistance to delousing chemicals. In response, farms now use a range of non-chemical delousing methods, including cleaner fish that eat lice from salmon. Anecdotal reports suggest that in regions where cleaner fish are extensively used on farms, lice have begun to appear less pigmented and therefore putatively less visible to cleaner fish. However, it remains an open question whether these observations reflect a plastic (environmental) or adaptive (genetic) response. To investigate this, we developed a pigment scoring system and conducted complimentary experiments which collectively demonstrate that, a) louse pigmentation is strongly influenced by environmental conditions, most likely light, and b) the presence of modest but significant differences in pigmentation between two strains of lice reared under identical conditions. Based on these data, we conclude that pigmentation in the salmon louse is strongly influenced by environmental conditions, yet there are also indications of underlying genetic control. Therefore, lice could display both plastic and adaptive responses to extensive cleaner fish usage where visual appearance is likely to influence survival of lice.
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Affiliation(s)
- Lars Are Hamre
- Department of Biological SciencesSea Lice Research CentreUniversity of BergenBergenNorway
| | | | | | - Frank Nilsen
- Department of Biological SciencesSea Lice Research CentreUniversity of BergenBergenNorway
- Institute of Marine ResearchBergenNorway
| | - Kevin Alan Glover
- Department of Biological SciencesSea Lice Research CentreUniversity of BergenBergenNorway
- Institute of Marine ResearchBergenNorway
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6
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Bateman AW, Peacock SJ, Krkošek M, Lewis MA. Migratory hosts can maintain the high-dose/refuge effect in a structured host-parasite system: The case of sea lice and salmon. Evol Appl 2020; 13:2521-2535. [PMID: 33294006 PMCID: PMC7691465 DOI: 10.1111/eva.12984] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 01/13/2023] Open
Abstract
Migration can reduce parasite burdens in migratory hosts, but it connects populations and can drive disease dynamics in domestic species. Farmed salmon are infested by sea louse parasites, often carried by migratory wild salmonids, resulting in a costly problem for industry and risk to wild populations when farms amplify louse numbers. Chemical treatment can control lice, but resistance has evolved in many salmon-farming regions. Resistance has, however, been slow to evolve in the north-east Pacific Ocean, where large wild-salmon populations harbour large sea louse populations. Using a mathematical model of host-macroparasite dynamics, we explored the roles of domestic, wild oceanic and connective migratory host populations in maintaining treatment susceptibility in associated sea lice. Our results show that a large wild salmon population, unexposed to direct infestation by lice from farms; high levels of on-farm treatment; and a healthy migratory host population are all critical to slowing or stopping the evolution of treatment resistance. Our results reproduce the "high-dose/refuge effect," from the agricultural literature, with the added requirement of a migratory host population to maintain treatment susceptibility. This work highlights the role that migratory hosts may play in shared wildlife/livestock disease, where evolution can occur in ecological time.
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Affiliation(s)
- Andrew W. Bateman
- Pacific Salmon FoundationVancouverBCCanada
- Salmon Coast Field StationSimoom SoundBCCanada
| | - Stephanie J. Peacock
- Salmon Coast Field StationSimoom SoundBCCanada
- Department of Biological SciencesUniversity of CalgaryCalgaryABCanada
| | - Martin Krkošek
- Salmon Coast Field StationSimoom SoundBCCanada
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
| | - Mark A. Lewis
- Department of Biological SciencesUniversity of AlbertaEdmontonABCanada
- Department of Mathematical and Statistical SciencesUniversity of AlbertaEdmontonABCanada
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7
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González-Gómez MP, Ovalle L, Spinetto C, Oyarzo C, Oyarzún R, Menanteau M, Álvarez D, Rivas M, Olmos P. Experimental transmission of Caligus rogercresseyi between two different fish species. DISEASES OF AQUATIC ORGANISMS 2020; 141:127-138. [PMID: 32969345 DOI: 10.3354/dao03513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Caligus rogercresseyi is the dominant sea louse parasite affecting the salmon and trout industry in southern Chile. This parasite has a wide range of native and endemic fish hosts. The Patagonian blenny Eleginops maclovinus, which is parasitized mostly by the caligid species Lepeophtheirus spp. and C. rogercresseyi, is presumably responsible for the transmission of C. rogercresseyi to salmonids. The aim of this study was to characterize the transmission of parasites between different fish species and parasite cohort development under laboratory conditions. Parasite abundances and intensities were quantified. Transmission of parasites from Patagonian blenny to Atlantic salmon Salmo salar was lower (~9%, mainly corresponding to C. rogercresseyi) than from salmon to Patagonian blenny (14.7-26.9%, where only C. rogercresseyi were observed). This suggests that the transmission of C. rogercresseyi from salmon individuals is higher than the transmission from a native fish. Parasite cohorts developed successfully on both fish species, but apparently under different developmental rates. Water temperature, oxygen, and juvenile abundances were the variables that better explained cohort development success and variation in C. rogercresseyi adult abundances over time.
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Affiliation(s)
- M P González-Gómez
- Departamento de Salud Hidrobiológica, Instituto de Fomento Pesquero, José Manuel Balmaceda 252, 5480000 Puerto Montt, Chile
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8
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Sea lice exposure to non-lethal levels of emamectin benzoate after treatments: a potential risk factor for drug resistance. Sci Rep 2020; 10:932. [PMID: 31969584 PMCID: PMC6976678 DOI: 10.1038/s41598-020-57594-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 01/03/2020] [Indexed: 11/24/2022] Open
Abstract
The avermectin derivative emamectin benzoate (EMB) has been widely used by salmon industries around the world to control sea lice infestations. Resistance to this anti-parasitic drug is also commonly reported in these industries. The objective of this study was to quantify the number of sea lice potentially exposed to sub-lethal concentrations of EMB while fish clear the drug after treatments. We assessed juvenile sea lice abundance after 38 EMB treatments on six Atlantic salmon farms, in a small archipelago in British Colombia, Canada, between 2007 and 2018. We fitted a standard EMB pharmacokinetic curve to determine the time when fish treated with this product would have EMB tissue concentrations below the recommended target therapeutic level. During the study, we estimated that for each sea lice treatment there was, on average, an abundance of 0.12 juvenile sea lice per fish during the time period when the concentrations of EMB would have been lower than 60ppb, the recommended therapeutic treatment level for sea lice. The findings from this study on metaphylactic anti-parasitic treatments identify a potential driver for drug resistance in sea lice that should be further explored.
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9
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González Gómez MP, Ovalle L, Menanteau M, Spinetto C, Oyarzún R, Rivas M, Oyarzo C. Susceptibility of Caligus rogercresseyi collected from the native fish species Eleginops maclovinus (Cuvier) to antiparasitics applied by immersion. JOURNAL OF FISH DISEASES 2019; 42:1143-1149. [PMID: 31094001 DOI: 10.1111/jfd.13020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/24/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
A major challenge for Chilean salmon farming is infestation by the ectoparasite Caligus rogercresseyi. In addition, there is evidence that a loss of chemotherapeutic treatment efficacy against important fish pathogens is occurring in salmon farming, including antiparasitic efficacy. Currently, there are known techniques that allow the determination of the susceptibility profile of parasites to antiparasitic treatment. However, there is scarce information about both threshold values and categorization of antiparasitic susceptibility for C. rogercresseyi. Bioassay technique allowed the determination of both mean values and the natural variation of EC50%, which were contrasted with available susceptibility thresholds. Results allowed to determine that parasites from the native fish host, Eleginops maclovinus, are susceptible to azamethiphos, deltamethrin and cypermethrin treatments, showing a high susceptibility profile to antiparasitics.
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Affiliation(s)
| | - Loreto Ovalle
- Departamento de Salud Hidrobiológica, Instituto de Fomento Pesquero, Puerto Montt, Chile
| | - Mylena Menanteau
- Departamento de Salud Hidrobiológica, Instituto de Fomento Pesquero, Puerto Montt, Chile
- Centro de Maricultura Hueihue, Instituto de Fomento Pesquero, Ancud, Chile
| | - Claudia Spinetto
- Departamento de Salud Hidrobiológica, Instituto de Fomento Pesquero, Puerto Montt, Chile
- Centro de Maricultura Hueihue, Instituto de Fomento Pesquero, Ancud, Chile
| | - Renato Oyarzún
- Departamento de Salud Hidrobiológica, Instituto de Fomento Pesquero, Puerto Montt, Chile
| | - Mario Rivas
- Departamento de Salud Hidrobiológica, Instituto de Fomento Pesquero, Puerto Montt, Chile
| | - Cristian Oyarzo
- Departamento de Salud Hidrobiológica, Instituto de Fomento Pesquero, Puerto Montt, Chile
- Centro de Maricultura Hueihue, Instituto de Fomento Pesquero, Ancud, Chile
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10
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McEwan GF, Groner ML, Cohen AAB, Imsland AKD, Revie CW. Modelling sea lice control by lumpfish on Atlantic salmon farms: interactions with mate limitation, temperature and treatment rules. DISEASES OF AQUATIC ORGANISMS 2019; 133:69-82. [PMID: 31089004 DOI: 10.3354/dao03329] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Atlantic salmon farming is one of the largest aquaculture sectors in the world. A major impact on farm economics, fish welfare and, potentially, nearby wild salmonid populations, is the sea louse ectoparasite Lepeophtheirus salmonis. Sea louse infestations are most often controlled through application of chemicals, but in most farming regions, sea lice have evolved resistance to the small set of available chemicals. Therefore, alternative treatment methodologies are becoming more widely used. One increasingly common alternative treatment involves the co-culture of farmed salmon with cleaner fish, which prey on sea lice. However, despite their wide use, little is understood about the situations in which cleaner fish are most effective. For example, previous work suggests that a low parasite density results in sea lice finding it difficult to acquire mates, reducing fecundity and population growth. Other work suggests that environmental conditions such as temperature and external sea louse pressure have substantial impact on this mate limitation threshold and may even remove the effect entirely. We used an Agent-Based Model (ABM) to simulate cleaner fish on a salmon farm to explore interactions between sea louse mating behaviour, cleaner fish feeding rate, temperature and external sea louse pressure. We found that sea louse mating has a substantial effect on sea louse infestations under a variety of environmental conditions. Our results suggest that cleaner fish can control sea louse infestations most effectively by maintaining the population below critical density thresholds.
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Affiliation(s)
- Gregor F McEwan
- Department of Health Management, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada
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11
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Cantrell DL, Rees EE, Vanderstichel R, Grant J, Filgueira R, Revie CW. The Use of Kernel Density Estimation With a Bio-Physical Model Provides a Method to Quantify Connectivity Among Salmon Farms: Spatial Planning and Management With Epidemiological Relevance. Front Vet Sci 2018; 5:269. [PMID: 30425996 PMCID: PMC6218437 DOI: 10.3389/fvets.2018.00269] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/08/2018] [Indexed: 01/08/2023] Open
Abstract
Connectivity in an aquatic setting is determined by a combination of hydrodynamic circulation and the biology of the organisms driving linkages. These complex processes can be simulated in coupled biological-physical models. The physical model refers to an underlying circulation model defined by spatially-explicit nodes, often incorporating a particle-tracking model. The particles can then be given biological parameters or behaviors (such as maturity and/or survivability rates, diel vertical migrations, avoidance, or seeking behaviors). The output of the bio-physical models can then be used to quantify connectivity among the nodes emitting and/or receiving the particles. Here we propose a method that makes use of kernel density estimation (KDE) on the output of a particle-tracking model, to quantify the infection or infestation pressure (IP) that each node causes on the surrounding area. Because IP is the product of both exposure time and the concentration of infectious agent particles, using KDE (which also combine elements of time and space), more accurately captures IP. This method is especially useful for those interested in infectious agent networks, a situation where IP is a superior measure of connectivity than the probability of particles from each node reaching other nodes. Here we illustrate the method by modeling the connectivity of salmon farms via sea lice larvae in the Broughton Archipelago, British Columbia, Canada. Analysis revealed evidence of two sub-networks of farms connected via a single farm, and evidence that the highest IP from a given emitting farm was often tens of kilometers or more away from that farm. We also classified farms as net emitters, receivers, or balanced, based on their structural role within the network. By better understanding how these salmon farms are connected to each other via their sea lice larvae, we can effectively focus management efforts to minimize the spread of sea lice between farms, advise on future site locations and coordinated treatment efforts, and minimize any impact of farms on juvenile wild salmon. The method has wide applicability for any system where capturing infectious agent networks can provide useful guidance for management or preventative planning decisions.
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Affiliation(s)
- Danielle L Cantrell
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Erin E Rees
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada.,Land and Sea Systems Analysis, Granby, QC, Canada
| | - Raphael Vanderstichel
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - Jon Grant
- Department of Oceanography, Dalhousie University, Halifax, NS, Canada
| | - Ramón Filgueira
- Marine Affairs Program, Dalhousie University, Halifax, NS, Canada
| | - Crawford W Revie
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
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12
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Gislason H. Statistical modelling of sea lice count data from salmon farms in the Faroe Islands. JOURNAL OF FISH DISEASES 2018; 41:973-993. [PMID: 29148591 DOI: 10.1111/jfd.12742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 07/17/2017] [Accepted: 09/14/2017] [Indexed: 06/07/2023]
Abstract
Fiskaaling regularly counts the number of sea lice in the attached development stages (chalimus, mobiles and adult) for the salmon farms in the Faroe Islands. A statistical model of the data is developed. In the model, the sea-lice infection is represented by the chalimus (or mobile) lice developing into adult lice and is used to simulate past and current levels of adult lice-including treatments-as well as to predict the adult sea lice level 1-2 months into the future. Time series of the chalimus and adult lice show cross-correlations that shift in time and grow in size with temperature. This implies in situ the temperature-dependent development times of about 56 down to 42 days and the inverted development times (growth rates) of 0.018 up to 0.024 lice/day at 8-10°C. The temperature dependence DT=α1T+α2α3=17,840T+7.439-2.128is approximated byD1T=105.2-6.578T≈49 days at the mean temperature 8.5°C-similar to DchaT=100.6-6.507T≈45 days from EWOS data. The observed development times at four sites for a year (2010-11) were 49, 50, 51 and 52 days, respectively. Finally, we estimate the sea lice production from fish farms to discuss approaches to control the sea lice epidemics-preferably by natural means. This study is useful for understanding sea lice levels and treatments, and for in situ analysis of the sea-lice development times and growth rates.
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Affiliation(s)
- H Gislason
- Faculty of Science and Technology, University of the Faroe Islands, Nóatún 3, FO-100 Tórshavn, Faroe Islands & Fiskaaling - Aquaculture Research Station of the Faroes, Við Áir 11, FO-430, Hvalvík, Faroe Islands
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13
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The Phe362Tyr mutation conveying resistance to organophosphates occurs in high frequencies in salmon lice collected from wild salmon and trout. Sci Rep 2017; 7:14258. [PMID: 29079820 PMCID: PMC5660183 DOI: 10.1038/s41598-017-14681-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 10/13/2017] [Indexed: 12/02/2022] Open
Abstract
The parasitic salmon louse, and its resistance to chemical delousing agents, represents one of the largest challenges to the salmon aquaculture industry. We genotyped lice sampled from wild salmon and sea trout throughout Norway with the recently identified Phe362Tyr mutation that conveys resistance to organophosphates. These results were compared to data from lice sampled on farmed salmon in the same regions. The resistant (R) allele was observed in salmon lice from wild salmon and sea trout throughout Norway, although its frequency was highest in farming-intense regions. In most regions, the frequency of the R allele was higher in lice collected from wild sea trout than wild Atlantic salmon, and in all regions, the frequency of the R allele was similar in lice collected from wild sea trout and farmed Atlantic salmon. The R allele is only selected for in fish-farms where organophosphates are used for delousing. Therefore, our results suggest extensive exchange of lice between farmed and wild hosts, and indicate that in farming-dense regions in Norway, aquaculture represents a major driver of salmon louse population structure. Finally, these data suggest that the wild hosts within the regions studied will not delay the spread of resistance when organophosphates are used.
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14
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McEwan GF, Groner ML, Burnett DL, Fast MD, Revie CW. Managing aquatic parasites for reduced drug resistance: lessons from the land. J R Soc Interface 2017; 13:rsif.2016.0830. [PMID: 28003529 DOI: 10.1098/rsif.2016.0830] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/28/2016] [Indexed: 11/12/2022] Open
Abstract
Atlantic salmon farming is one of the largest aquaculture industries in the world. A major problem in salmon farms is the sea louse ectoparasite Lepeophtheirus salmonis, which can cause stress, secondary infection and sometimes mortality in the salmon host. Sea lice have substantial impacts on farm economics and potentially nearby wild salmonid populations. The most common method of controlling sea louse infestations is application of chemicals. However, most farming regions worldwide have observed resistance to the small set of treatment chemicals that are available. Despite this, there has been little investigation of treatment strategies for managing resistance in aquaculture. In this article, we compare four archetypical treatment strategies inspired by agriculture, where the topic has a rich history of study, and add a fifth strategy common in aquaculture. We use an agent-based model (ABM) to simulate these strategies and their varying applications of chemicals over time and space. We analyse the ABM output to compare how the strategies perform in controlling louse abundance, number of treatments required and levels of resistance in the sea louse population. Our results indicated that among the approaches considered applying chemicals in combination was the most effective over the long term.
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Affiliation(s)
- Gregor F McEwan
- Centre for Veterinary and Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Maya L Groner
- Departments of Fisheries Management and Aquatic Health Sciences, Virginia Institute of Marine Science, 1375 Greate Road, Gloucester Point, VA 23062-1346, USA
| | - Danielle L Burnett
- Centre for Veterinary and Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Mark D Fast
- Hoplite Research Group, Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Crawford W Revie
- Centre for Veterinary and Epidemiological Research, Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, Canada C1A 4P3
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15
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Kreitzman M, Ashander J, Driscoll J, Bateman AW, Chan KMA, Lewis MA, Krkosek M. Wild Salmon Sustain the Effectiveness of Parasite Control on Salmon Farms: Conservation Implications from an Evolutionary Ecosystem Service. Conserv Lett 2017. [DOI: 10.1111/conl.12395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Maayan Kreitzman
- Institute for Resources, Environment, and Sustainability; University of British Columbia; 429-2202 Main Mall (4th floor) Vancouver BC V6T 1Z4 Canada
| | - Jaime Ashander
- Department of Environmental Science & Policy; University of California; One Shields Ave Davis Davis CA 95616 USA
| | - John Driscoll
- Institute for Resources, Environment, and Sustainability; University of British Columbia; 429-2202 Main Mall (4th floor) Vancouver BC V6T 1Z4 Canada
| | - Andrew W Bateman
- Department of Biological Sciences, University of Alberta CW 405; Biological Sciences Bldg.; Edmonton AB T6G 2E9 Canada
- Salmon Coast Field Station; General Delivery, Simoom Sound BC V0P 1S0 Canada
| | - Kai M. A. Chan
- Institute for Resources, Environment, and Sustainability; University of British Columbia; 429-2202 Main Mall (4th floor) Vancouver BC V6T 1Z4 Canada
| | - Mark A. Lewis
- Department of Biological Sciences, University of Alberta CW 405; Biological Sciences Bldg.; Edmonton AB T6G 2E9 Canada
- Department of Mathematical and Statistical Sciences; University of Alberta; 545B CAB Edmonton AB T6G 2G1 Canada
| | - Martin Krkosek
- Salmon Coast Field Station; General Delivery, Simoom Sound BC V0P 1S0 Canada
- Department of Ecology and Evolutionary Biology; University of Toronto; 25 Willcocks Street Toronto Ontario M5S 3B2 Canada
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16
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Myhre Jensen E, Sevatdal S, Bakke MJ, Kaur K, Horsberg TE. A selection study on a laboratory-designed population of salmon lic (Lepeophtheirus salmonis) using organophosphate and pyrethroid pesticides. PLoS One 2017; 12:e0178068. [PMID: 28531206 PMCID: PMC5439706 DOI: 10.1371/journal.pone.0178068] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/08/2017] [Indexed: 11/30/2022] Open
Abstract
Resistance towards antiparasitic agents in the salmon louse (Lepeophtheirus salmonis) is a widespread problem along the Norwegian coast, reducing treatments efficacies and slowing down the envisioned expansion of Norwegian salmon production. The present study was conducted in order to assess the efficacies of two of the most widely used anti-parasitic substances–azamethiphos and deltamethrin–as well as assessing the benefit of having a resistant genotype compared to being fully sensitive when exposed to one of these substances. Atlantic salmon were exposed to a mix of salmon lice copepodids from a fully sensitive, a double resistant and a multi-resistant strain. Once the lice reached pre-adult stages, one group was exposed to 100 μg/L azamethiphos for 60 minutes, the other to 2 μg/L deltamethrin for 30 minutes, and the last was kept in a seawater control. Detached lice were collected at a series of time points following exposure, and all lice (immobilized and surviving) were analysed for both pyrethroid (sensitive “S” and resistant “R”) and azamethiphos (fully sensitive “SS”, heterozygous resistant “RS” and fully resistant “RR”) resistance markers. We found that the efficacies of deltamethrin on parasites with genotype S and R were 70.3 and 13.2%, respectively. The overall efficacy of the deltamethrin treatment was 32.3%. The efficacies of azamethiphos on parasites with genotype SS, RS and RR were 100, 80 and 19.1%, respectively. The overall efficacy of the azamethiphos treatment was 80.4%. Survival analyses revealed that the median survival time in deltamethrin-sensitive and–resistant parasites were 16.8 and >172 hours, respectively. The differences were even more pronounced in the azamethiphos-treated group, where SS, RS and RR parasites survived for 0.26, 6.6 and >172 hours, respectively. The substantial differences in survival between sensitive and resistant lice following treatment demonstrate the ability of medicinal treatments to drive genetic selection towards a much more resistant salmon lice population within a very short time span if there is no influx of sensitive genotypes.
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Affiliation(s)
- Elena Myhre Jensen
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Sea Lice Research Centre, Oslo, Norway
- * E-mail:
| | | | - Marit Jørgensen Bakke
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Sea Lice Research Centre, Oslo, Norway
| | - Kiranpreet Kaur
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Sea Lice Research Centre, Oslo, Norway
| | - Tor Einar Horsberg
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine, Sea Lice Research Centre, Oslo, Norway
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17
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Ugelvik MS, Skorping A, Moberg O, Mennerat A. Evolution of virulence under intensive farming: salmon lice increase skin lesions and reduce host growth in salmon farms. J Evol Biol 2017; 30:1136-1142. [DOI: 10.1111/jeb.13082] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 01/05/2023]
Affiliation(s)
- M. S. Ugelvik
- Department of Biology; University of Bergen; Bergen Norway
| | - A. Skorping
- Department of Biology; University of Bergen; Bergen Norway
| | - O. Moberg
- Department of Biology; University of Bergen; Bergen Norway
| | - A. Mennerat
- Department of Biology; University of Bergen; Bergen Norway
- Ecologie et Dynamique des Systèmes Anthropisés (FRE 3498); CNRS/Université de Picardie Jules Verne; Amiens France
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18
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Rudman SM, Kreitzman M, Chan KMA, Schluter D. Evosystem Services: Rapid Evolution and the Provision of Ecosystem Services. Trends Ecol Evol 2017; 32:403-415. [PMID: 28336183 DOI: 10.1016/j.tree.2017.02.019] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 02/23/2017] [Accepted: 02/24/2017] [Indexed: 12/21/2022]
Abstract
Evolution is recognized as the source of all organisms, and hence many ecosystem services. However, the role that contemporary evolution might play in maintaining and enhancing specific ecosystem services has largely been overlooked. Recent advances at the interface of ecology and evolution have demonstrated how contemporary evolution can shape ecological communities and ecosystem functions. We propose a definition and quantitative criteria to study how rapid evolution affects ecosystem services (here termed contemporary evosystem services) and present plausible scenarios where such services might exist. We advocate for the direct measurement of contemporary evosystem services to improve understanding of how changing environments will alter resource availability and human well-being, and highlight the potential utility of managing rapid evolution for future ecosystem services.
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Affiliation(s)
- Seth M Rudman
- Department of Zoology, University of British Columbia, 4200-6270 University Blvd, Vancouver, BC V6T 1Z4, Canada.
| | - Maayan Kreitzman
- Institute for Resources, Environment, and Sustainability, University of British Columbia, 429-2202 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Kai M A Chan
- Institute for Resources, Environment, and Sustainability, University of British Columbia, 429-2202 Main Mall, Vancouver, BC V6T 1Z4, Canada
| | - Dolph Schluter
- Department of Zoology, University of British Columbia, 4200-6270 University Blvd, Vancouver, BC V6T 1Z4, Canada
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19
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Groner ML, Rogers LA, Bateman AW, Connors BM, Frazer LN, Godwin SC, Krkošek M, Lewis MA, Peacock SJ, Rees EE, Revie CW, Schlägel UE. Lessons from sea louse and salmon epidemiology. Philos Trans R Soc Lond B Biol Sci 2016; 371:rstb.2015.0203. [PMID: 26880836 DOI: 10.1098/rstb.2015.0203] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Effective disease management can benefit from mathematical models that identify drivers of epidemiological change and guide decision-making. This is well illustrated in the host-parasite system of sea lice and salmon, which has been modelled extensively due to the economic costs associated with sea louse infections on salmon farms and the conservation concerns associated with sea louse infections on wild salmon. Consequently, a rich modelling literature devoted to sea louse and salmon epidemiology has been developed. We provide a synthesis of the mathematical and statistical models that have been used to study the epidemiology of sea lice and salmon. These studies span both conceptual and tactical models to quantify the effects of infections on host populations and communities, describe and predict patterns of transmission and dispersal, and guide evidence-based management of wild and farmed salmon. As aquaculture production continues to increase, advances made in modelling sea louse and salmon epidemiology should inform the sustainable management of marine resources.
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Affiliation(s)
- Maya L Groner
- Department of Health Management, Centre for Veterinary and Epidemiological Research, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Luke A Rogers
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2
| | - Andrew W Bateman
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2 Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 Salmon Coast Field Station, Simoom Sound, British Columbia, Canada V0P 1S0
| | - Brendan M Connors
- Salmon Coast Field Station, Simoom Sound, British Columbia, Canada V0P 1S0 ESSA Technologies Ltd, Vancouver, British Columbia, Canada V6H 3H4 School of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - L Neil Frazer
- Salmon Coast Field Station, Simoom Sound, British Columbia, Canada V0P 1S0 Department of Geology and Geophysics, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
| | - Sean C Godwin
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6
| | - Martin Krkošek
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2 Salmon Coast Field Station, Simoom Sound, British Columbia, Canada V0P 1S0
| | - Mark A Lewis
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9 Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2G1
| | - Stephanie J Peacock
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2E9
| | - Erin E Rees
- Department of Health Management, Centre for Veterinary and Epidemiological Research, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Crawford W Revie
- Department of Health Management, Centre for Veterinary and Epidemiological Research, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, Prince Edward Island, Canada C1A 4P3
| | - Ulrike E Schlägel
- Department of Mathematical and Statistical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G 2G1
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20
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21
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Rittenhouse MA, Revie CW, Hurford A. A model for sea lice (Lepeophtheirus salmonis) dynamics in a seasonally changing environment. Epidemics 2016; 16:8-16. [DOI: 10.1016/j.epidem.2016.03.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 03/22/2016] [Accepted: 03/25/2016] [Indexed: 11/28/2022] Open
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22
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Predicting the effectiveness of depth-based technologies to prevent salmon lice infection using a dispersal model. Prev Vet Med 2016; 129:48-57. [DOI: 10.1016/j.prevetmed.2016.05.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 04/01/2016] [Accepted: 05/20/2016] [Indexed: 11/19/2022]
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23
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Jansen PA, Grøntvedt RN, Tarpai A, Helgesen KO, Horsberg TE. Surveillance of the Sensitivity towards Antiparasitic Bath-Treatments in the Salmon Louse (Lepeophtheirus salmonis). PLoS One 2016; 11:e0149006. [PMID: 26889677 PMCID: PMC4759459 DOI: 10.1371/journal.pone.0149006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 01/26/2016] [Indexed: 11/18/2022] Open
Abstract
The evolution of drug resistant parasitic sea lice is of major concern to the salmon farming industry worldwide and challenges sustainable growth of this enterprise. To assess current status and development of L. salmonis sensitivity towards different pesticides used for parasite control in Norwegian salmon farming, a national surveillance programme was implemented in 2013. The programme aims to summarize data on the use of different pesticides applied to control L. salmonis and to test L. salmonis sensitivity to different pesticides in farms along the Norwegian coast. Here we analyse two years of test-data from biological assays designed to detect sensitivity-levels towards the pesticides azamethiphos and deltamethrin, both among the most common pesticides used in bath-treatments of farmed salmon in Norway in later years. The focus of the analysis is on how different variables predict the binomial outcome of the bioassay tests, being whether L. salmonis are immobilized/die or survive pesticide exposure. We found that local kernel densities of bath treatments, along with a spatial geographic index of test-farm locations, were significant predictors of the binomial outcome of the tests. Furthermore, the probability of L. salmonis being immobilized/dead after test-exposure was reduced by odds-ratios of 0.60 (95% CI: 0.42–0.86) for 2014 compared to 2013 and 0.39 (95% CI: 0.36–0.42) for low concentration compared to high concentration exposure. There were also significant but more marginal effects of parasite gender and developmental stage, and a relatively large random effect of test-farm. We conclude that the present data support an association between local intensities of bath treatments along the coast and the outcome of bioassay tests where salmon lice are exposed to azamethiphos or deltamethrin. Furthermore, there is a predictable structure of L. salmonis phenotypes along the coast in the data, characterized by high susceptibility to pesticides in the far north and far south, but low susceptibility in mid Norway. The study emphasizes the need to address local susceptibility to pesticides and the need for restrictive use of pesticides to preserve treatment efficacy.
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Affiliation(s)
- Peder A. Jansen
- Norwegian Veterinary Institute, Oslo, Norway
- Sea Lice Research Centre, Department of Biology, University of Bergen, Bergen, Norway
- * E-mail:
| | | | | | - Kari O. Helgesen
- NMBU School of Veterinary Science, Sea Lice Research Centre, Oslo, Norway
| | - Tor Einar Horsberg
- NMBU School of Veterinary Science, Sea Lice Research Centre, Oslo, Norway
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