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Geographic and temporal genetic structure in Lepeophtheirus salmonis from four salmon farms along the northwest and west coasts of Ireland: results from a microsatellite analysis

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Abstract

The marine ectoparasitic copepod of salmonids, Lepeophtheirus salmonis (Krøyer), is a major pest of farmed Atlantic salmon (Salmo salar L.) causing great economic impact. The spatial scales over which L. salmonis populations in different salmon farms are typically connected, and the temporal scales over which L. salmonis from the same farm typically undergo genetic change are largely unknown. These questions were posed in a small-scale geographic study of population structure in L. salmonis from four salmon farms, along the northwest and west coasts of Ireland, using two outgroups from Norway and Canada. The temporal stability of genetic composition was also studied in samples collected quarterly during one year from one salmon farm in Ireland. Genetic composition in L. salmonis was characterised using four nuclear microsatellites. Significant but low genetic differentiation was observed between all sites (F ST = 0.08), with no evidence that differentiation was correlated with geographic distance. Temporal genetic differentiation was also evident (F ST = 0.07). An analysis of all L. salmonis samples except the ones from Norway detected two separate clusters. Each cluster contained both geographical and temporal samples. These results are consistent with a population model in which L. salmonis in salmon farms along the northwest and west coasts of Ireland are not isolated, but are potentially subject to (i) localised ecological factors at the particular farm sites or (ii) selection post-settlement or a combination thereof.

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References

  • Belkhir, K., P. Borsa, L. Chikhi, N. Raufaste & F. Bonhomme, 2000. GENETIX version 4.03, logiciel sous Windows pour la génétique des populations. Laboratoire Génome, Populations, Interactions, Universite de Montpellier, II, France.

  • Costello, M. J., 2006. Ecology of sea lice parasitic on farmed and wild fish. TRENDS in Parasitology 22(10): 475–481.

    Article  PubMed  Google Scholar 

  • Dixon, B. A., A. P. Shinn & C. Sommerville, 2004. Genetic characterization of populations of the ectoparasitic caligid, Lepeophtheirus salmonis (Krøyer 1837) using randomly amplified polymorphic DNA. Aquaculture Research 35: 730–741.

    Article  CAS  Google Scholar 

  • Felsenstein, J., 1993. PHYLIP (Phylogeny Inference Package) Version 3.5c. Department of Genetics, University of Washington, Seattle. Distributed by the author.

  • Guo, S. W. & E. A. Thompson, 1992. Performing the exact test of Hardy–Weinberg proportion for multiple alleles. Biometrics 48: 361–372.

    Article  PubMed  CAS  Google Scholar 

  • Heuch, P. A., P. A. Bjørn, B. Finstad, J. C. Holst, L. Asplin & F. Nilsen, 2005. A review of the Norwegian “National action plan against salmon lice on salmonids”: the effect on wild salmonids. Aquaculture 246: 79–92.

    Article  Google Scholar 

  • Isdal, E., A. Nylund & G. Nævdal, 1997. Genetic differences among salmon lice (Lepeophtheirus salmonis) from six Norwegian coastal sites: evidence from allozymes. Bulletin of the European Association of Fish Pathologists 17: 17–22.

    Google Scholar 

  • Jackson, D. & D. Minchin, 1992. Aspects of the reproductive output of two caligid copepod species on cultivated salmon. Invertebrate Reproduction and Development 22: 87–90.

    Google Scholar 

  • Johnson, S. C., J. W. Treasurer, S. Bravo, K. Nagasawa & Z. Kabata, 2004. A review of the impact of parasitic copepods on marine aquaculture. Zoological Studies 43: 229–243.

    Google Scholar 

  • Jones, S. R. M., G. Prosperi-Porta, E. Kim, P. Callow & N. B. Hargreaves, 2006. The occurrence of Lepeophtheirus salmonis and Caligus clemensi (Copepoda: Caligidae) on three-spine stickleback Gasterosteus aculeatus in coastal British Columbia. Journal of Parasitology 92: 473–480.

    Article  PubMed  Google Scholar 

  • Mantel, N., 1967. The detection of disease clustering and a generalised regression approach. Cancer Research 27: 209–220.

    PubMed  CAS  Google Scholar 

  • Michalakis, Y. & L. Excoffier, 1996. A generic estimation of population subdivision using distances between alleles with special reference for microsatellite loci. Genetics 142: 1061–1064.

    PubMed  CAS  Google Scholar 

  • Nolan, D. V., S. A. M. Martin, Y. Kelly, K. Glennon, T. Smith, G. P. McCormack & R. Powell, 2000a. Development of microsatellite PCR typing methodology for the sea louse, Lepeophtheirus salmonis (Krøyer). Aquaculture Research 31: 815–822.

    Article  Google Scholar 

  • Nolan, D. T., N. M. Ruane, Y. van der Heijden, E. S. Quabius, J. Costelloe & S. E. W. Bonga, 2000b. Juvenile Lepeophtheirus salmonis (Krøyer) affect the skin and gills of rainbow trout, Oncorhynchus mykiss (Walbaum), and the host response to a handling procedure. Aquaculture Research 31: 823–833.

    Article  Google Scholar 

  • Pike, A. W. & S. L. Wadsworth, 1999. Sea lice on salmonids: their biology and control. Advances in Parasitology 44: 234–337.

    Article  Google Scholar 

  • Raymond, M. & F. Rousset, 1995. GENEPOP version 1.2—population genetics software for exact tests and ecumenicism. Journal of Heredity 86: 248–249.

    Google Scholar 

  • Shinn, A. P., B. A. Banks, N. Tange, A. P. Bron, C. Sommerville, T. Aoki & R. Wooten, 2000. Utility of the 18S rDNA and ITS sequences as population markers for Lepeophtheirus salmonis (Copepoda: Caligidae) parasitising Atlantic salmon (Salmo salar) in Scotland. Contributions to Zoology 69: 79–87.

    Google Scholar 

  • Slatkin, M. & L. Excoffier, 1996. Testing for linkage disequilibrium in genotypic data using the expectation-maximization algorithm. Heredity 76: 377–383.

    Article  PubMed  Google Scholar 

  • Todd, C. D., A. M. Walker, M. G. Ritchie, J. A. Graves & A. F. Walker, 2004. Population genetic differentiation of sea lice (Lepeophtheirus salmonis) parasitic on Atlantic and Pacific salmonids: analyses of microsatellite DNA variation among wild and farmed hosts. Canadian Journal of Fisheries and Aquatic Sciences 61: 1176–1190.

    Article  CAS  Google Scholar 

  • Todd, C. D., A. M. Walker, K. Wolff, S. J. Northcott, A. F. Walker, M. G. Ritchie, R. Hoskins, R. J. Abbott & N. Hazon, 1997. Genetic differentiation of populations of the copepod sea louse Lepeophtheirus salmonis (Krøyer) ectoparasitic on wild and farmed salmonids around the coasts of Scotland: evidence from RAPD markers. Journal of Experimental Marine Biology and Ecology 210: 251–274.

    Article  Google Scholar 

  • Tully, O. & D. T. Nolan, 2002. A review of the population biology and host–parasite interaction of the sea louse Lepeophtheirus salmonis (Copepoda: Caligidae). Parasitology 124: 165–182.

    Article  Google Scholar 

  • Tully, O. & K. F. Whelan, 1993. Production of nauplii of Lepeophtheirus salmonis (Krøyer) (Copepoda: Caligidae) from farmed and wild salmon and its relation to the infestation of wild sea trout (Salmo trutta L.) off the west coast of Ireland in 1991. Fisheries Research 17: 187–200.

    Article  Google Scholar 

  • Walker, A. F., 1994. Sea trout and salmon stocks in the western highlands. In Shelton, R. G. J. (ed.), Problems with Sea Trout and Salmon in the Western Highlands. Atlantic Salmon Trust, Pitlochry: 6–18.

    Google Scholar 

  • Weir, B. S. & C. C. Cockerham, 1984. Estimating F-statistics for the analysis of population structure. Evolution 38: 1358–1370.

    Article  Google Scholar 

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Acknowledgements

This research was supported by the E.U. supported Operational Programme for Fisheries (Contract 97.IR.MR.011) coordinated by the Marine Institute, Ireland. The gifts of sea lice from Alan Walker and Christopher Todd (Scotland), Per Gunnar Kvenseth and Anne-Mette Kvenseth (Norway), John F. Burka of the Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island (Canada), and David Jackson and Dan Hassett of the Marine Institute (Ireland) are gratefully acknowledged. D. V. Nolan was supported by an N.U.I., Galway postgraduate fellowship. The preparation of this paper was delayed by the untimely death of Dr. Richard Powell and is hereby dedicated to his memory.

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Authors and Affiliations

  1. Department of Microbiology, National University of Ireland, Galway, Ireland

    Damien V. Nolan & Richard Powell

  2. School of Biological Sciences, University of Aberdeen, Aberdeen, Scotland, UK

    Damien V. Nolan

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  1. Damien V. Nolan
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  2. Richard Powell
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Correspondence to Damien V. Nolan.

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R. Powell—deceased.

Guest editors: S. Souissi & G. A. Boxshall

Copepoda in the Mediterranean: Papers from the 9th International Conference on Copepoda, Hammamet, Tunisia

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Nolan, D.V., Powell, R. Geographic and temporal genetic structure in Lepeophtheirus salmonis from four salmon farms along the northwest and west coasts of Ireland: results from a microsatellite analysis. Hydrobiologia 617, 55–63 (2009). https://doi.org/10.1007/s10750-008-9525-7

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