Space-time cluster analysis of sea lice infestation (Caligus clemensi and Lepeophtheirus salmonis) on wild juvenile Pacific salmon in the Broughton Archipelago of Canada

Overview
TitleSpace-time cluster analysis of sea lice infestation (Caligus clemensi and Lepeophtheirus salmonis) on wild juvenile Pacific salmon in the Broughton Archipelago of Canada
AuthorsPatanasatienkul T, Sanchez J, Rees EE, Pfeiffer D, Revie CW
TypeJournal Article
Journal NamePreventive veterinary medicine
VolumeN/A
IssueN/A
Year2015
Page(s)N/A
CitationPatanasatienkul T, Sanchez J, Rees EE, Pfeiffer D, Revie CW. Space-time cluster analysis of sea lice infestation (Caligus clemensi and Lepeophtheirus salmonis) on wild juvenile Pacific salmon in the Broughton Archipelago of Canada. Preventive veterinary medicine. 2015 Mar 17.

Abstract

Sea lice infestation levels on wild chum and pink salmon in the Broughton Archipelago region are known to vary spatially and temporally; however, the locations of areas associated with a high infestation level had not been investigated yet. In the present study, the multivariate spatial scan statistic based on a Poisson model was used to assess spatial clustering of elevated sea lice (Caligus clemensi and Lepeophtheirus salmonis) infestation levels on wild chum and pink salmon sampled between March and July of 2004 to 2012 in the Broughton Archipelago and Knight Inlet regions of British Columbia, Canada. Three covariates, seine type (beach and purse seining), fish size, and year effect, were used to provide adjustment within the analyses. The analyses were carried out across the five months/datasets and between two fish species to assess the consistency of the identified clusters. Sea lice stages were explored separately for the early life stages (non-motile) and the late life stages of sea lice (motile). Spatial patterns in fish migration were also explored using monthly plots showing the average number of each fish species captured per sampling site. The results revealed three clusters for non-motile C. clemensi, two clusters for non-motile L. salmonis, and one cluster for the motile stage in each of the sea lice species. In general, the location and timing of clusters detected for both fish species were similar. Early in the season, the clusters of elevated sea lice infestation levels on wild fish are detected in areas closer to the rivers, with decreasing relative risks as the season progresses. Clusters were detected further from the estuaries later in the season, accompanied by increasing relative risks. In addition, the plots for fish migration exhibit similar patterns for both fish species in that, as expected, the juveniles move from the rivers toward the open ocean as the season progresses The identification of space-time clustering of infestation on wild fish from this study can help in targeting investigations of factors associated with these infestations and thereby support the development of more effective sea lice control measures.

Author Details
Additional information about authors:
Details
1Thitiwan Patanasatienkul
2Javier Sanchez
3Erin E Rees
4Dirk Pfeiffer
5Crawford W Revie
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Property NameValue
CopyrightCopyright © 2015 Elsevier B.V. All rights reserved.
Publication ModelPrint-Electronic
ISSN1873-1716
eISSN1873-1716
Publication Date2015 Mar 17
Journal AbbreviationPrev. Vet. Med.
Elocation10.1016/j.prevetmed.2015.03.006
LanguageEnglish
Language AbbrENG
Publication TypeJournal Article
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PMID: PMID:25869117