Commercial trials using emamectin benzoate to control sea lice Lepeophtheirus salmonis infestations in Atlantic salmon Salmo salar

Overview
TitleCommercial trials using emamectin benzoate to control sea lice Lepeophtheirus salmonis infestations in Atlantic salmon Salmo salar
AuthorsStone J, Sutherland IH, Sommerville C, Richards RH, Varma KJ
TypeClinical Trial
Media TitleDiseases of aquatic organisms
Volume41
Issue2
Year2000
Page(s)141-9
CitationStone J, Sutherland IH, Sommerville C, Richards RH, Varma KJ. Commercial trials using emamectin benzoate to control sea lice Lepeophtheirus salmonis infestations in Atlantic salmon Salmo salar. Diseases of aquatic organisms. 2000 Jun 19; 41(2):141-9.

Abstract

Two trials were conducted at commercial salmon farms to evaluate the efficacy of emamectin benzoate (Slice, 0.2% aquaculture pre-mix, Schering-Plough Animal Health) as a treatment for sea lice Lepeophtheirus salmonis (Krøyer) and Caligus elongatus Nordmann infestations in Atlantic salmon Salmo salar L. Trials were carried out in 15 m2 commercial sea pens, at temperatures of 5.5 to 7.5 degrees C and 10.8 to 13.8 degrees C. Each pen was stocked with 14,000 to 17,500 fish with mean weights of 0.44 to 0.74 and 1.33 to 1.83 kg. Fish were naturally infested with sea lice at the start of each trial. At Day -1, samples of 10 or 15 fish were taken from each pen to determine pre-treatment numbers of lice. Emamectin benzoate was administered in feed, to 4 replicate pens, at a dose of 50 micrograms kg-1 biomass d-1 for 7 consecutive days (Days 0 to 6). Sea lice were counted again, between Days 7 and 77, and comparisons made with untreated control fish. Despite adverse weather conditions, wide variations in fish weights and exposure to new infestations, treatment was effective against chalimus and motile stages of L. salmonis. In the autumn trial, efficacy at Day 27 was 89%, and lice numbers remained lower on treated fish than on control fish 64 d from the start of treatment. In the winter trial, reductions in lice numbers at low temperatures were slower but good efficacy was achieved by Day 35. Although control fish had to be treated with hydrogen peroxide at Day 21, fish treated only with emamectin benzoate on Days 0 to 6 still had 89% fewer lice than control fish at Day 35. There were very few C. elongatus present, but at the end of both trials numbers were lower on treated fish. No adverse effects were associated with treatment of fish with emamectin benzoate.

Author Details
Additional information about authors:
Details
1J Stone
2I H Sutherland
3C Sommerville
4R H Richards
5K J Varma
Properties
Additional details for this publication include:
Property NameValue
Publication ModelPrint
ISSN0177-5103
pISSN0177-5103
Publication Date2000 Jun 19
Journal AbbreviationDis. Aquat. Org.
LanguageEnglish
Language Abbreng
Publication TypeClinical Trial
Journal CountryGERMANY
Publication TypeJournal Article
Publication TypeResearch Support, Non-U.S. Gov't
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DatabaseAccession
PMID: PMID:10918982