Noise‐induced reduction in the attack rate of a planktivorous freshwater fish revealed by functional response analysis

Abstract

Anthropogenic noise can affect animals physically, physiologically, and behaviourally. Although individual responses to noise are well documented, the consequences in terms of community structure, species coexistence, and ecosystem functioning remain fairly unknown. The impact of noise on predation has received a growing interest and alterations in trophic links are observed when animals shift from foraging to stress‐related behaviours, are distracted by noise, or because of acoustic masking. However, the experimental procedures classically used to quantify predation do not inform on the potential demographic impact on prey. We derived the relationship between resource use and availability (the functional response) for European minnows (Phoxinus phoxinus) feeding on dipteran larvae (Chaoborus sp.) under two noise conditions: ambient noise and ambient noise supplemented with motorboat noise. The shape and magnitude of the functional response are powerful indicators of population outcomes and predator–prey dynamics. We also recorded fish behaviour to explore some proximate determinants of altered predation. For both noise conditions, fish displayed a saturating (type II) functional response whose shape depends on two parameters: attack rate and handling time. Boat noise did not affect handling time but significantly reduced attack rate, resulting in a functional response curve of the same height but with a less steep initial slope. Fish exhibited a stress‐related response to noise including increased swimming distance, more social interactions, and altered spatial distribution. Our study shows the usefulness of the functional response approach to study the ecological impacts of noise and illustrates how the behavioural responses of predators to noise can modify the demographic pressure on prey. It also suggests that prey availability might mediate the negative effect of noise on predation. Community outcomes are expected if the reduced consumption of the main food sources goes with the overconsumption of alternative food sources, changing the distribution pattern of interaction strengths. Predation release could also trigger a trophic cascade, propagating the effect of noise to lower trophic levels.

From distraction to habituation: Ecological and behavioural responses of invasive fish to anthropogenic noise

“…We expected to find type II (i.e. decelerating) FRs, the FR type usually displayed by fish in shelter-free experimental arenas (Alexander et al, 2014(Alexander et al, , 2015Hanache et al, 2020;Laverty et al, 2017). Under noise, stress could manifest itself through behaviour with altered swimming distance (either increased or decreased depending on the species, Voellmy et al, 2014), avoidance of the sound source (De Robertis & Handegard, 2013) and more social interactions (Voellmy et al, 2014).…”

Fish from urban rivers and with high pollutant levels have shorter telomeres

“…In fact, fish from urban and agricultural rivers did not differ in their pollutant load, except for slightly higher plasticizer and pesticide levels in urban watercourses. Urban river systems have however undergone profound changes, such as damming, banking and channelization that have led to the disruption of longitudinal connectivity, and loss of wetlands and spawning grounds, but also increased water temperature, pathogens and boat noise [45,46,47]. Our study suggests that the diverse and profound degradation of urban streams induces deleterious effects in fish by accelerating telomere attrition and probably jeopardizing their survival.…”

Six steps towards operationalising freshwater ecoacoustic monitoring

“…This information can be used to build automatic classification algorithms, as can the characterisations by Grabowski, Young, and Cott (2020), who analysed spawning calls by soniferous burbot in northern Canada. Automatic detection algorithms are now widespread in terrestrial and marine systems, F I G U R E 3 Ecoacoustics can detect and monitor: (a) water-dependent birds and amphibians (Dema et al, 2020;Dutilleux & Curé, 2020;Indraswari et al, 2020;Linke & Deretic, 2020); (b) activity of aquatic insects and other invertebrates (Desjonquères, Rybak, et al, 2020;Gottesman et al, 2020;Linke, Decker, et al, 2020); (c) communication between fish (Grabowski et al, 2020;Hanache et al, 2020;Higgs & Humphrey, 2020;Linke, Decker, et al, 2020;Roca et al, 2020;Rountree & Juanes, 2020); (d) biophysical processes such as sediment transport and gas exchange (Gottesman et al, 2020;Linke, Decker, et al, 2020); (e) anthropogenic disturbance, for example boat and engine noises (Desjonquères, Rybak, et al, 2020;Higgs & Humphrey, 2020) [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…Two other studies did not describe noise as a proxy, but as a direct effect. Both Hanache et al (2020) and Roca, Magnan and Proulx (2020) described changed feeding behaviour of two fish species in relation to ambient noise. The former study in particular discussed farther reaching consequences of noise pollution-noise can modify predator behaviour and therefore change the entire food web.…”

“…Ecoacoustics can detect and monitor: (a) water‐dependent birds and amphibians (Dema et al, ; Dutilleux & Curé, ; Indraswari et al, ; Linke & Deretic, ); (b) activity of aquatic insects and other invertebrates (Desjonquères, Rybak, et al, ; Gottesman et al, ; Linke, Decker, et al, ); (c) communication between fish (Grabowski et al, ; Hanache et al, ; Higgs & Humphrey, ; Linke, Decker, et al, ; Roca et al, ; Rountree & Juanes, ); (d) biophysical processes such as sediment transport and gas exchange (Gottesman et al, ; Linke, Decker, et al, ); (e) anthropogenic disturbance, for example boat and engine noises (Desjonquères, Rybak, et al, ; Higgs & Humphrey, ) [Colour figure can be viewed at wileyonlinelibrary.com]…”