The reaction distance of a planktivorous fish (Scardinius erythrophthalmus) and the evasiveness of its prey (Daphnia pulex\u2009\xd7\u2009pulicaria) under different artificial light spectra

Joanna Tałanda,Ewa Babkiewicz,Piotr Maszczyk

doi:10.1007/s10201-018-0548-0

Abstract

Artificial light at night may affect mortality risk in prey from visually oriented predators because the effect of the artificial light spectrum may differ for a predator’s visual prey detection and for prey evasiveness. To test this, we conducted two types of experiment. First, we assessed the reaction distance and swimming speed of juvenile rudd (Scardinius erythrophthalmus) allowed to forage on juvenile Daphnia pulex × pulicaria under three artificial light sources: halogen, high pressure sodium (HPS), and metal halide bulbs, at the same light intensity. Second, we assessed the evasiveness of D. pulex × pulicaria under the same artificial light sources and in darkness (as a control), in the presence and absence of chemical information on predation risk (kairomones) of juvenile rudd. We found that while both reaction distance and swimming speed of fish was greater under halogen compared to HPS, and similar under metal halide light compared to halogen and HPS, the evasiveness of Daphnia was greater under halogen and HPS-generated light than under metal halide light. The results suggest a possible mismatch of Daphnia’s behavioural response under metal halide light to predicted predation risk, and thus a possible threat to predator–prey balance in a lake ecosystem.

Highlights

Increasing exposure to artificial light relating to human activity at night is considered a serious threat to organisms today (Hölker et al 2010)
Our study revealed that the swimming speed of rudd was greater in halogen than in high pressure sodium (HPS) light
This is consistent with the results obtained in earlier studies, in which the greater swimming speed of fish correlated with better visual conditions, which was attributed to better visibility and greater foraging activity (Batty et al 1990; Gjelland et al 2004; Onsrud et al 2005; Utne-Palm 1999)

Summary

Introduction

Increasing exposure to artificial light relating to human activity at night is considered a serious threat to organisms today (Hölker et al 2010). Nocturnal illumination disrupts the natural cycle of light and darkness in various ecosystems, generating a specific type of pollution called ecological light pollution (Longcore and Rich 2004). It has been shown that artificial light at night can alter predator–prey interactions The number of studies on light pollution is increasing from year to year, little is known about aquatic ecosystems, they require particular attention (Brüning et al 2011; Moore et al.2001; Perkin et al 2011; Perkin et al 2014)

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