Dual-band fluorosensor for discriminating non-eating from algae-eating zooplankton in aquatic environments

J. H. Nielsen*, C. Pedersen, Thomas Kiørboe, Thomas Nikolajsen, M. Brydegaard, Peter John Rodrigo

*Corresponding author for this work

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We present a fluorosensor for the detection of laser-induced autofluorescence of zooplankton in marine environments. The sensor uses an inexpensive 410 nm laser diode as excitation source and simultaneously measures two fluorescence bands, 500-550 nm and 675-725 nm, using two identical 16-bit linear array detectors. We show continuous measurements at 200 Hz of zooplankton swimming through a water volume illuminated by the 410 nm laser. The sensor can distinguish salmon lice (Lepeophtheirus salmonis) larvae from an algae-eating reference species (Acartia tonsa) with a sensitivity of up to 99%. The system successfully differentiates the two species using mixed-species cultures at different ratios. This work shows the potential of fluorescent pest monitoring in the salmon farming industry and paves the way for single-ended aquatic lidars.

Original languageEnglish
JournalOSA Continuum
Issue number7
Pages (from-to)1730-1738
Publication statusPublished - 2020

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