Identifying 'firebreaks' to fragment dispersal networks of a marine parasite

TitleIdentifying 'firebreaks' to fragment dispersal networks of a marine parasite
AuthorsSamsing F, Johnsen I, Treml EA, Dempster T
TypeJournal Article
Journal NameInternational journal for parasitology
CitationSamsing F, Johnsen I, Treml EA, Dempster T. Identifying 'firebreaks' to fragment dispersal networks of a marine parasite. International journal for parasitology. 2019 Jan 17.


Marine ecosystems are beset by disease outbreaks, and efficient strategies to control dispersal of pathogens are scarce. We tested whether introducing no-farming areas or 'firebreaks' could disconnect dispersal networks of a parasitic disease affecting the world's largest marine fish farming industry (∼1000 farms). Larval salmon lice (Lepeophtheirus salmonis) are released from and transported among salmon farms by ocean currents, creating inter-farm networks of louse dispersal. We used a state-of-the-art biophysical model to predict louse movement along the Norwegian coastline and network analysis to identify firebreaks to dispersal. At least one firebreak that fragmented the network into two large unconnected groups of farms was identified for all seasons. During spring, when wild salmon migrate out into the ocean, and louse levels per fish at farms must be minimised, two effective firebreaks were created by removing 13 and 21 farms (1.3% and 2.2% of all farms in the system) at ∼61°N and 67°N, respectively. We have demonstrated that dispersal models coupled with network analysis can identify no-farming zones that fragment dispersal networks. Reduced dispersal pathways should lower infection pressure at farms, slow the evolution of resistance to parasite control measures, and alleviate infection pressure on wild salmon populations.

Author Details
Additional information about authors:
1Francisca Samsing
2Ingrid Johnsen
3Eric A Treml
4Tim Dempster
Additional details for this publication include:
Property NameValue
Publication ModelPrint-Electronic
Publication Date2019 Jan 17
Journal AbbreviationInt. J. Parasitol.
CopyrightCopyright © 2019 Australian Society for Parasitology. All rights reserved.
Language Abbreng
Publication TypeJournal Article
Journal CountryEngland
Cross References
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PMID: PMID:30660636