Illuminating the planktonic stages of salmon lice: A unique fluorescence signal for rapid identification of a rare copepod in zooplankton assemblages

Overview
TitleIlluminating the planktonic stages of salmon lice: A unique fluorescence signal for rapid identification of a rare copepod in zooplankton assemblages
AuthorsThompson CRS, Bron JE, Bui S, Dalvin S, Fordyce MJ, Furmanek T, Á Norði G, Skern-Mauritzen R
TypeJournal Article
Journal NameJournal of fish diseases
VolumeN/A
IssueN/A
Year2021
Page(s)N/A
CitationThompson CRS, Bron JE, Bui S, Dalvin S, Fordyce MJ, Furmanek T, Á Norði G, Skern-Mauritzen R. Illuminating the planktonic stages of salmon lice: A unique fluorescence signal for rapid identification of a rare copepod in zooplankton assemblages. Journal of fish diseases. 2021 Feb 15.

Abstract

Monitoring of planktonic salmon louse (Lepeophtheirus salmonis salmonis) abundance and parameterization of key life-history traits has been hindered by labour-intensive and error-prone quantification using traditional light microscopy. Fluorescence illumination has been proposed as a means of improving visualization, but prior to this study adequate investigation of the relevant fluorescence profiles and measurement conditions has not been undertaken. We investigated the fluorescence profiles of L. salmonis and non-target copepod spp. with excitation and emission matrices (200-600 nm) and identified unique fluorescence signals. Fluorescence microscopy using excitation wavelengths of 470 ± 40 nm, and emission wavelengths of 525 ± 50 nm, showed that after 90 days of formalin storage salmon lice have a mean fluorescence intensity that is 2.4 times greater than non-target copepods (copepodid and adult stages). A 7-day heat treatment of 42°C in formalin increased the difference between salmon louse copepodids and non-target copepods to a factor of 3.6, eliminating the need for prolonged storage. Differences in the fluorescence signal and endogenous fluorophores were investigated with respect to variation in sea lice species, age, stage and host fish origin. Under the conditions outlined in this paper, the fluorescence signal was found to be a reliable means of visualizing and differentiating salmon lice from non-target zooplankters. Adaptation of the fluorescence signal would greatly expedite traditional methods of enumerating salmon louse larvae in plankton samples and could provide a means of automated detection.

Properties
Additional details for this publication include:
Property NameValue
Journal CountryEngland
Publication TypeJournal Article
Language Abbreng
LanguageEnglish
Copyright© 2021 The Authors. Journal of Fish Diseases published by John Wiley & Sons Ltd.
Elocation10.1111/jfd.13345
DOI10.1111/jfd.13345
Journal AbbreviationJ Fish Dis
Publication Date2021 Feb 15
eISSN1365-2761
ISSN1365-2761
Publication ModelPrint-Electronic
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PMID: PMID:33586246