1
|
Chang T, Hunt BPV, Hirai J, Suttle CA. Divergent RNA viruses infecting sea lice, major ectoparasites of fish. PLoS Pathog 2023; 19:e1011386. [PMID: 37347729 DOI: 10.1371/journal.ppat.1011386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 04/25/2023] [Indexed: 06/24/2023] Open
Abstract
Sea lice, the major ectoparasites of fish, have significant economic impacts on wild and farmed finfish, and have been implicated in the decline of wild salmon populations. As blood-feeding arthropods, sea lice may also be reservoirs for viruses infecting fish. However, except for two groups of negative-strand RNA viruses within the order Mononegavirales, nothing is known about viruses of sea lice. Here, we used transcriptomic data from three key species of sea lice (Lepeophtheirus salmonis, Caligus clemensi, and Caligus rogercresseyi) to identify 32 previously unknown RNA viruses. The viruses encompassed all the existing phyla of RNA viruses, with many placed in deeply branching lineages that likely represent new families and genera. Importantly, the presence of canonical virus-derived small interfering RNAs (viRNAs) indicates that most of these viruses infect sea lice, even though in some cases their closest classified relatives are only known to infect plants or fungi. We also identified both viRNAs and PIWI-interacting RNAs (piRNAs) from sequences of a bunya-like and two qin-like viruses in C. rogercresseyi. Our analyses showed that most of the viruses found in C. rogercresseyi occurred in multiple life stages, spanning from planktonic to parasitic stages. Phylogenetic analysis revealed that many of the viruses infecting sea lice were closely related to those that infect a wide array of eukaryotes with which arthropods associate, including fungi and parasitic tapeworms, implying that over evolutionary time there has been cross-phylum and cross-kingdom switching of viruses between arthropods and other eukaryotes. Overall, this study greatly expands our view of virus diversity in crustaceans, identifies viruses that infect and replicate in sea lice, and provides evidence that over evolutionary time, viruses have switched between arthropods and eukaryotic hosts in other phyla and kingdoms.
Collapse
Affiliation(s)
- Tianyi Chang
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - Brian P V Hunt
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, Canada
- Hakai Institute, Campbell River, Canada
| | - Junya Hirai
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
| | - Curtis A Suttle
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, Canada
- Hakai Institute, Campbell River, Canada
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Botany, University of British Columbia, Vancouver, Canada
| |
Collapse
|
2
|
Morefield RD, Hamlin HJ. Larval salmon lice Lepeophtheirus salmonis exhibit behavioral responses to conspecific pre-adult and adult cues. DISEASES OF AQUATIC ORGANISMS 2022; 149:121-132. [PMID: 35678357 DOI: 10.3354/dao03666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In the larval stage of the parasitic copepod Lepeophtheirus salmonis, the free-living copepodid must locate and settle on a salmonid host. Chemosensory mechanisms play a role in determining whether a potential host is suitable for attachment, yet the full suite of chemical cues and resulting behavioral mechanisms used are unknown. After maturing, pre-adult female and adult male salmon lice aggregate upon salmonid hosts for reproduction. Copepodid salmon lice have been observed preferentially infesting hosts that harbor conspecific adults. The aim of this study was to investigate the possibility that salmon lice copepodids perceive and respond to cues from pre-adult female, adult-male, and/or gravid female salmon lice. Behavioral bioassays were conducted in vitro with copepodids exposed to water conditioned with 3 stages of conspecific lice (pre-adult female, adult male, or gravid female), and seawater conditioned with Atlantic salmon Salmo salar Linnaeus, 1758. Experiments demonstrated that copepodids exposed to water conditioned with the salmon host, pre-adult female, or adult male salmon lice significantly altered their behavior, whereas salmon lice exposed to water conditioned with gravid females did not. These results are potentially valuable in the development of novel methods for mitigation of L. salmonis in the salmon aquaculture industry.
Collapse
Affiliation(s)
- Robert D Morefield
- School of Marine Sciences, Murray Hall, University of Maine, Orono, ME 04469, USA
| | | |
Collapse
|
3
|
Firkus TJ, Goetz FW, Fischer G, Murphy CA. The Influence of Life History on the Response to Parasitism: Differential response to non-lethal sea lamprey parasitism by two lake charr ecomorphs. Integr Comp Biol 2022; 62:104-120. [PMID: 35026028 PMCID: PMC9375137 DOI: 10.1093/icb/icac001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The energetic demands of stressors like parasitism require hosts to reallocate energy away from normal physiological processes to survive. Life history theory provides predictions about how hosts will reallocate energy following parasitism, but few studies provide empirical evidence to test these predictions. We examined the sub-lethal effects of sea lamprey parasitism on lean and siscowet lake charr, two ecomorphs with different life history strategies. Leans are shorter lived, faster growing, and reach reproductive maturity earlier than siscowets. Following a parasitism event of 4 days, we assessed changes to energy allocation by monitoring endpoints related to reproduction, energy storage, and growth. Results indicate that lean and siscowet lake charr differ considerably in their response to parasitism. Severely parasitized leans slightly increased their reproductive effort and maintained growth and energy storage, consistent with expectations based on life history that leans are less likely to survive parasitism and have shorter lifespans than siscowets making investing in immediate reproduction more adaptive. Siscowets nearly ceased reproduction following severe parasitism and showed evidence of altered energy storage, consistent with a strategy that favors maximizing long-term reproductive success. These findings suggest that life history can be used to generalize stressor response between populations and can aid management efforts.
Collapse
Affiliation(s)
- Tyler J Firkus
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| | - Frederick W Goetz
- Great Lakes WATER Institute, University of Wisconsin-Milwaukee, Milwaukee, WI 53204, USA
| | - Gregory Fischer
- Northern Aquaculture Demonstration Facility, University of Wisconsin-Stevens Point, Bayfield, WI 54814, USA
| | - Cheryl A Murphy
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA
| |
Collapse
|
4
|
Godwin SC, Krkošek M, Reynolds JD, Bateman AW. Bias in self-reported parasite data from the salmon farming industry. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02226. [PMID: 32896013 DOI: 10.1002/eap.2226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/01/2020] [Accepted: 07/20/2020] [Indexed: 06/11/2023]
Abstract
Many industries are required to monitor themselves in meeting regulatory policies intended to protect the environment. Self-reporting of environmental performance can place the cost of monitoring on companies rather than taxpayers, but there are obvious risks of bias, often addressed through external audits or inspections. Surprisingly, there have been relatively few empirical analyses of bias in industry self-reported data. Here, we test for bias in reporting of environmental compliance data using a unique data set from Canadian salmon farms, where companies monitor the number of parasitic sea lice on fish in open sea pens, in order to minimize impacts on wild fish in surrounding waters. We fit a hierarchical population-dynamics model to these sea-louse count data using a Bayesian approach. We found that the industry's monthly counts of two sea-louse species, Caligus clemensi and Lepeophtheirus salmonis, increased by a factor of 1.95 (95% credible interval: 1.57, 2.42) and 1.18 (1.06, 1.31), respectively, in months when counts were audited by the federal fisheries department. Consequently, industry sea-louse counts are less likely to trigger costly but mandated delousing treatments intended to avoid sea-louse epidemics in wild juvenile salmon. These results highlight the potential for combining external audits of industry self-reported data with analyses of their reporting to maintain compliance with regulations, achieve intended conservation goals, and build public confidence in the process.
Collapse
Affiliation(s)
- Sean C Godwin
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
- Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia, B3H 4R2, Canada
| | - Martin Krkošek
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, M5S 3B2, Canada
- Salmon Coast Field Station, General Delivery, Simoom Sound, British Columbia, V0P 1S0, Canada
| | - John D Reynolds
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
| | - Andrew W Bateman
- Salmon Coast Field Station, General Delivery, Simoom Sound, British Columbia, V0P 1S0, Canada
- Department of Geography, University of Victoria, 3800 Finnerty Road, Victoria, British Columbia, V8P 5C2, Canada
| |
Collapse
|
5
|
Shea D, Bateman A, Li S, Tabata A, Schulze A, Mordecai G, Ogston L, Volpe JP, Neil Frazer L, Connors B, Miller KM, Short S, Krkošek M. Environmental DNA from multiple pathogens is elevated near active Atlantic salmon farms. Proc Biol Sci 2020; 287:20202010. [PMID: 33081614 PMCID: PMC7661312 DOI: 10.1098/rspb.2020.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The spread of infection from reservoir host populations is a key mechanism for disease emergence and extinction risk and is a management concern for salmon aquaculture and fisheries. Using a quantitative environmental DNA methodology, we assessed pathogen environmental DNA in relation to salmon farms in coastal British Columbia, Canada, by testing for 39 species of salmon pathogens (viral, bacterial, and eukaryotic) in 134 marine environmental samples at 58 salmon farm sites (both active and inactive) over 3 years. Environmental DNA from 22 pathogen species was detected 496 times and species varied in their occurrence among years and sites, likely reflecting variation in environmental factors, other native host species, and strength of association with domesticated Atlantic salmon. Overall, we found that the probability of detecting pathogen environmental DNA (eDNA) was 2.72 (95% CI: 1.48, 5.02) times higher at active versus inactive salmon farm sites and 1.76 (95% CI: 1.28, 2.42) times higher per standard deviation increase in domesticated Atlantic salmon eDNA concentration at a site. If the distribution of pathogen eDNA accurately reflects the distribution of viable pathogens, our findings suggest that salmon farms serve as a potential reservoir for a number of infectious agents; thereby elevating the risk of exposure for wild salmon and other fish species that share the marine environment.
Collapse
Affiliation(s)
- Dylan Shea
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada
| | - Andrew Bateman
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.,Salmon Coast Field Station, Simoom Sound, British Columbia, Canada.,Pacific Salmon Foundation, Vancouver, British Columbia, Canada
| | - Shaorong Li
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Amy Tabata
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Angela Schulze
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Gideon Mordecai
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lindsey Ogston
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada
| | - John P Volpe
- School of Environmental Studies, University of Victoria, Victoria, British Columbia, Canada
| | - L Neil Frazer
- Department of Earth Sciences, University of Hawaii at Mānoa, Honolulu, Hawaii, Canada
| | - Brendan Connors
- Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia, Canada
| | - Kristina M Miller
- Pacific Biological Station, Fisheries and Oceans Canada, Nanaimo, British Columbia, Canada
| | - Steven Short
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.,Department of Biology, University of Toronto Mississauga, Mississauga, British Columbia, Canada
| | - Martin Krkošek
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada.,Salmon Coast Field Station, Simoom Sound, British Columbia, Canada
| |
Collapse
|
6
|
Atkinson EM, Bateman AW, Dill LM, Krkošek M, Reynolds JD, Godwin SC. Oust the louse: leaping behaviour removes sea lice from wild juvenile sockeye salmon Oncorhynchus nerka. JOURNAL OF FISH BIOLOGY 2018; 93:263-271. [PMID: 29956312 DOI: 10.1111/jfb.13684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/02/2018] [Indexed: 06/08/2023]
Abstract
We conducted a manipulative field experiment to determine whether the leaping behaviour of wild juvenile sockeye salmon Oncorhynchus nerka dislodges ectoparasitic sea lice Caligus clemensi and Lepeophtheirus salmonis by comparing sea-lice abundances between O. nerka juveniles prevented from leaping and juveniles allowed to leap at a natural frequency. Juvenile O. nerka allowed to leap had consistently fewer sea lice after the experiment than fish that were prevented from leaping. Combined with past research, these results imply potential costs due to parasitism and indicate that the leaping behaviour of juvenile O. nerka does, in fact, dislodge sea lice.
Collapse
Affiliation(s)
- Emma M Atkinson
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Andrew W Bateman
- Department of Geography, University of Victoria, Victoria, British Columbia, Canada
- Salmon Coast Field Station, Simoom Sound, British Columbia, Canada
| | - Lawrence M Dill
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Martin Krkošek
- Salmon Coast Field Station, Simoom Sound, British Columbia, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - John D Reynolds
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Sean C Godwin
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| |
Collapse
|
7
|
Halttunen E, Gjelland KØ, Hamel S, Serra-Llinares RM, Nilsen R, Arechavala-Lopez P, Skarðhamar J, Johnsen IA, Asplin L, Karlsen Ø, Bjørn PA, Finstad B. Sea trout adapt their migratory behaviour in response to high salmon lice concentrations. JOURNAL OF FISH DISEASES 2018; 41:953-967. [PMID: 29159923 DOI: 10.1111/jfd.12749] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/21/2017] [Accepted: 09/24/2017] [Indexed: 05/25/2023]
Abstract
Sea trout face growth-mortality trade-offs when entering the sea to feed. Salmon lice epizootics resulting from aquaculture have shifted these trade-offs, as salmon lice might both increase mortality and reduce growth of sea trout. We studied mortality and behavioural adaptations of wild sea trout in a large-scale experiment with acoustic telemetry in an aquaculture intensive area that was fallowed (emptied of fish) synchronically biannually, creating large variations in salmon lice concentrations. We tagged 310 wild sea trout during 3 years, and gave half of the individuals a prophylaxis against further salmon lice infestation. There was no difference in survival among years or between treatments. In years of high infestation pressure, however, sea trout remained closer to the river outlet, used freshwater (FW) habitats for longer periods and returned earlier to the river than in the low infestation year. This indicates that sea trout adapt their migratory behaviour by actively choosing FW refuges from salmon lice to escape from immediate mortality risk. Nevertheless, simulations show that these adaptations can lead to lost growth opportunities. Reduced growth can increase long-term mortality of sea trout due to prolonged exposure to size-dependent predation risk, lead to lower fecundity and, ultimately, reduce the likelihood of sea migration.
Collapse
Affiliation(s)
- E Halttunen
- Institute of Marine Research (IMR), Tromsø, Norway
| | - K-Ø Gjelland
- Norwegian Institute for Nature Research (NINA), Trondheim, Norway
| | - S Hamel
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, The Arctic University of Norway, Tromsø, Norway
| | | | - R Nilsen
- Institute of Marine Research (IMR), Tromsø, Norway
| | - P Arechavala-Lopez
- Department of Marine Sciences and Applied Biology, University of Alicante, Alicante, Spain
- Department of Ecology of Marine Resources, Mediterranean Institute for Advanced Studies, Esporles, Mallorca, Spain
| | - J Skarðhamar
- Institute of Marine Research (IMR), Tromsø, Norway
| | - I A Johnsen
- Institute of Marine Research (IMR), Bergen, Norway
| | - L Asplin
- Institute of Marine Research (IMR), Bergen, Norway
| | - Ø Karlsen
- Institute of Marine Research (IMR), Bergen, Norway
| | - P-A Bjørn
- Institute of Marine Research (IMR), Tromsø, Norway
| | - B Finstad
- Norwegian Institute for Nature Research (NINA), Trondheim, Norway
| |
Collapse
|
8
|
Fogel D, Fuentes JL, Soto LM, Lafuente W, Moncayo-Estrada R, López C. Ectoparasitic copepod infestation on a wild population of Neotropical catfish Sciades herzbergii Bloch, 1794: Histological evidences of lesions on host. Int J Parasitol Parasites Wildl 2017; 6:344-348. [PMID: 29379712 PMCID: PMC5779637 DOI: 10.1016/j.ijppaw.2017.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/27/2017] [Accepted: 10/05/2017] [Indexed: 10/31/2022]
Abstract
We analyzed the infestation of the attached copepod species Lepeophtheirus sp on a wild population of Sciades herzbergii. The infestation and occurrence of attached copepods were related to body size, maturity and sex of host and the presence of lesions on fish skin were described. In 61 fish specimens (37 males and 24 females), total of 218 ectoparasitic copepods, including 204 mature and 14 immature stages were found. Copepods were attached to different regions of fish body without any regular pattern. The prevalence of infestation was 80.3% and intensity between 1 and 15 copepods/fish. No significant differences were found between sex or maturity and the presence of attached Lepeophtheirus sp. However, a contingency table including both sex and maturity status, and the total number of attached copepod per combined category showed a significant association. A positive correlation was found between body length of fish and intensity of infestation. Similarly, when comparing the infested fish according to group size, we found more copepods on larger individual. Attached copepods were associated with the presence of lesions visible to the naked eye. Histological analyses showed changes in cell architecture when sections of copepod-free tissues and attached copepods were compared.
Collapse
Affiliation(s)
- Deborah Fogel
- Programa de Maestría en Ciencias Biológicas, mención Ecología Acuática, División de Estudios para Graduados, Facultad Experimental de Ciencias, Universidad del Zulia, Maracaibo, Venezuela
| | - José Luis Fuentes
- Centro Regional de Investigaciones Ambientales, Universidad de Oriente, Venezuela
| | - Luz Marina Soto
- Escuela Superior Politécnica del Litoral, ESPOL, Carrera de Biología, Facultad de Ciencias de la Vida, Campo Gustavo Galindo, Km. 30,5 Vía Perimetral, Guayaquil, Ecuador
| | - Wilson Lafuente
- Escuela Superior Politécnica del Litoral, ESPOL, Carrera de Biología, Facultad de Ciencias de la Vida, Campo Gustavo Galindo, Km. 30,5 Vía Perimetral, Guayaquil, Ecuador
| | - Rodrigo Moncayo-Estrada
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, COFAA, La Paz, Baja California Sur, Mexico
| | - Carlos López
- Escuela Superior Politécnica del Litoral, ESPOL, Carrera de Biología, Facultad de Ciencias de la Vida, Campo Gustavo Galindo, Km. 30,5 Vía Perimetral, Guayaquil, Ecuador
| |
Collapse
|