Sea lice infestation levels decrease with deeper 'snorkel' barriers in Atlantic salmon sea-cages

Overview
TitleSea lice infestation levels decrease with deeper 'snorkel' barriers in Atlantic salmon sea-cages
AuthorsOppedal F, Samsing F, Dempster T, Wright DW, Bui S, Stien LH
TypeJournal Article
Journal NamePest management science
VolumeN/A
IssueN/A
Year2017
Page(s)N/A
CitationOppedal F, Samsing F, Dempster T, Wright DW, Bui S, Stien LH. Sea lice infestation levels decrease with deeper 'snorkel' barriers in Atlantic salmon sea-cages. Pest management science. 2017 Mar 01.

Abstract

BACKGROUND
Salmon lice (Lepeophtheirus salmonis) are the most important parasite of farmed salmon. Infective larvae position themselves in the upper part of the water column to increase encounter probabilities with potential hosts. Previous studies have shown that a 'snorkel' sea-cage technology protects salmon from infection in surface waters. We tested whether deep snorkels would more effectively reduce lice infestation than shallow snorkels and still uphold adequate conditions for the fish. Five sea-cages (12 m × 12 m) each holding approximately 3000 Atlantic salmon (Salmo salar) (53 ± 10 g) were fitted with snorkels that gave protection from infection for 0, 4, 8, 12 or 16 m. We tested if reductions in the settlement of new salmon lice copepodids were consistent among 4 separate infection periods.

RESULTS
Lice infestation decreased exponentially with depth in all time periods. Infection levels in shallow snorkels (0 and 4 m) were consistently four to ten times higher than those in deep snorkels (12 and 16 m). Key welfare and production performance indices were similar across all snorkel depths.

CONCLUSION
Deeper snorkels dramatically and consistently reduced infection levels of salmon lice compared to shallow snorkels without consequences for fish welfare and production performance. Therefore, reducing salmon sea lice encounters using a depth-based barrier is a powerful management tool for salmon farming.

Author Details
Additional information about authors:
Details
1Frode Oppedal
2Francisca Samsing
3Tim Dempster
4Daniel W Wright
5Samantha Bui
6Lars H Stien
Properties
Additional details for this publication include:
Property NameValue
Publication ModelPrint-Electronic
ISSN1526-4998
eISSN1526-4998
Publication Date2017 Mar 01
Journal AbbreviationPest Manag. Sci.
DOI10.1002/ps.4560
Elocation10.1002/ps.4560
Journal CountryEngland
CopyrightThis article is protected by copyright. All rights reserved.
LanguageEnglish
Language Abbreng
Publication TypeJournal Article
Cross References
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DatabaseAccession
PMID: PubMedPMID:28247541