Assessing effects of increased noise levels on fish behaviour

Man-made noise can affect physiology and behaviour of animals of all taxa, including fish. However, there is not much known about effects of increased noise levels on anti-predator and foraging behaviour, which are both essential for survival and reproduction. In our laboratory study, we investigated effects of increased noise levels on these behaviours in two sympatric fish species, three-spined sticklebacks (Gasterosteus aculeatus) and European minnows (Phoxinus phoxinus), which differ in their anti-predator defences and likely in their hearing capabilities. Our study indicated that both behavioural contexts were affected by increased noise levels, but effects differed between species. Sticklebacks responded to a visual predatory stimulus sooner when exposed to additional noise playbacks than in control conditions, whereas minnows were not affected by the noise treatments. In foraging experiments, both fish species consumed fewer water fleas, but the reasons fish decreased food consumption seemed species specific: sticklebacks increased the number of foraging errors, whereas minnows tended to decrease their foraging effort by interacting socially more often and more individuals were inactive during increased noise level conditions. To allow for controlled comparative experiments, our studies were conducted in the laboratory. Complementary field experiments ensuring natural acoustic conditions will be necessary to investigate whether species differences can translate into community effects and whether these effects differ between different kinds of noise, such as drilling, pile driving and energy device operation noise. Expanding research to commercially important fish and quantification of particle motion in addition to sound pressure as most fish, and likely invertebrate species, perceive particle motion rather than sound pressure, would further deliver valuable knowledge for industry, policy makers and fisheries managers about how marine renewable energy devices may interfere with the marine environment.University of BristolBasler Stiftung für Biologische ForschungDefraNER

Increased noise levels have different impacts on the anti-predator behaviour of two sympatric fish species.

types: Journal ArticleCopyright: © 2014 Voellmy et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Animals must avoid predation to survive and reproduce, and there is increasing evidence that man-made (anthropogenic) factors can influence predator-prey relationships. Anthropogenic noise has been shown to have a variety of effects on many species, but work investigating the impact on anti-predator behaviour is rare. In this laboratory study, we examined how additional noise (playback of field recordings of a ship passing through a harbour), compared with control conditions (playback of recordings from the same harbours without ship noise), affected responses to a visual predatory stimulus. We compared the anti-predator behaviour of two sympatric fish species, the three-spined stickleback (Gasterosteus aculeatus) and the European minnow (Phoxinus phoxinus), which share similar feeding and predator ecologies, but differ in their body armour. Effects of additional-noise playbacks differed between species: sticklebacks responded significantly more quickly to the visual predatory stimulus during additional-noise playbacks than during control conditions, while minnows exhibited no significant change in their response latency. Our results suggest that elevated noise levels have the potential to affect anti-predator behaviour of different species in different ways. Future field-based experiments are needed to confirm whether this effect and the interspecific difference exist in relation to real-world noise sources, and to determine survival and population consequences.University of BristolBasler Stiftung für Biologische ForschungDefr

Can sleep and resting behaviours be used as indicators of welfare in shelter dogs (Canis lupusfamiliaris)?

Previous research on humans and animals suggests that the analysis of sleep patterns may reliably inform us about welfare status, but little research of this kind has been carried out for non-human animals in an applied context. This study explored the use of sleep and resting behaviour as indicators of welfare by describing the activity patterns of dogs (Canis lupus familiaris) housed in rescue shelters, and comparing their sleep patterns to other behavioural and cognitive measures of welfare. Sleep and activity patterns were observed over five non-consecutive days in a population of 15 dogs. Subsequently, the characteristics of sleep and resting behaviour were described and the impact of activity on patterns of sleep and resting behaviour analysed. Shelter dogs slept for 2.8% of the day, 14.3% less than previously reported and experienced less sleep fragmentation at night (32 sleep bouts). There were no statistically significant relationships between behaviours exhibited during the day and sleep behaviour. A higher proportion of daytime resting behaviour was significantly associated with a positive judgement bias, less repetitive behaviour and increased time spent coded as ‘relaxed’ across days by shelter staff. These results suggest that, in the context of a busy shelter environment, the ability to rest more during the day could be a sign of improved welfare. Considering the non-linear relationship between sleep and welfare in humans, the relationship between sleep and behavioural indicators of welfare, including judgement bias, in shelter dogs may be more complex than this study could detect

Environmental noise reduces predation rate in an aquatic invertebrate

Noise is one of a wide range of disturbances associated with human activities that have been shown to have detrimental impacts on a wide range of species, from montane regions to the deep marine environment. Noise may also have community-level impacts via predator–prey interactions, thus jeopardising the stability of trophic networks. However, the impact of noise on freshwater ecosystems is largely unknown. Even more so is the case of insects, despite their crucial role in trophic networks. Here, we study the impact of underwater noise on the predatory functional response of damselfly larvae. We compared the feeding rates of larvae under anthropogenic noise, natural noise, and silent conditions. Our results suggest that underwater noise (pooling the effects of anthropogenic noise and natural noise) decreases the feeding rate of damselflies significantly compared to relatively silent conditions. In particular, natural noise increased the handling time significantly compared to the silent treatment, thus reducing the feeding rate. Unexpectedly, feeding rates under anthropogenic noise were not reduced significantly compared to silent conditions. This study suggests that noise per se may not necessarily have negative impacts on trophic interactions. Instead, the impact of noise on feeding rates may be explained by the presence of nonlinearities in acoustic signals, which may be more abundant in natural compared to anthropogenic noise. We conclude by highlighting the importance of studying a diversity of types of acoustic pollution, and encourage further work regarding trophic interactions with insects using a functional response approach

Underwater noise emission from the NOAH’s drilling operation at the narec site, Blyth, UK

In November 2011, the National Renewable Energy Center (narec) launched their offshore wind demonstrator project 'round 3'. Narec commissioned SeaRoc to undertake the deployment and drilling operation of the Narec Offshore Anemometric Hub (NOAH). On this occasion, the Bio-Acoustic Research Consortium combining university and industry researchers conducted a study on noise and marine mammal occurrence before, during and after installation of the Noah platform. This paper describes the noise emission from the installation of the NOAH's jacket. The team preliminary undertook underwater ambient noise measurements at different seasons, and locations at the site. The results of these measurements are discussed in this paper. The pin pile drilling itself occurred at 3 nautical miles offshore Blyth and at a 40 m depth. The Newcastle research vessel Princess Royal was positioned at 500m and 3 nautical miles from the NOAH's drilling. The engine and all electronic equipment on board, such as sonar and depth sensors were switched off during the pin pile drilling noise monitoring. At each position, a self-recorder hydrophone was deployed from a semi-submersible drifting buoy to reduce the effect of the swell (sea state 3), which could have affected the quality of the recordings. The deployment from a drifting buoy also has the advantage of reducing mechanical noise from the boat as the buoy drifts freely away from the vessel. Each recording lasted between 5 and 10 minutes and the buoy was then retrieved for another deployment at the next position. Sample measurements were taken at approximately 10 m depth and at a sampling rate of 312 kHz and 24 bits resolution. Matlab was used as a post-processing tool to analyse the data. Each file was processed on a 2 min average using a FFT of 216 points. The in-house code displays Sound Pressure Level (dB re1µParms) and Pressure Spectral Density (dB re1µParms2/Hz) with a 1Hz resolution. The results demonstrate that the noise coming from the pin pile drilling was relatively low in comparison to the background noise. At 500 m from the drilling, the noise appears to be only 10 to 20 dB higher than the background noise over the frequency band 10 Hz to 50 kHz. Higher energy was concentrated between 100 Hz and 600 Hz reaching up to 100 dB re1µParms.Natural Environment Research Counci

Motorboat noise disrupts co-operative interspecific interactions

Human-made noise is contributing increasingly to ocean soundscapes. Its physical, physiological and behavioural effects on marine organisms are potentially widespread, but our understanding remains largely limited to intraspecific impacts. Here, we examine how motorboats affect an interspecific cleaning mutualism critical for coral reef fish health, abundance and diversity. We conducted in situ observations of cleaning interactions between bluestreak cleaner wrasses (Labroides dimidiatus) and their fish clients before, during and after repeated, standardised approaches with motorboats. Cleaners inspected clients for longer and were significantly less cooperative during exposure to boat noise, and while motorboat disturbance appeared to have little effect on client behaviour, as evidenced by consistency of visit rates, clientele composition, and use of cleaning incitation signals, clients did not retaliate as expected (i.e., by chasing) in response to increased cheating by cleaners. Our results are consistent with the idea of cognitive impairments due to distraction by both parties. Alternatively, cleaners might be taking advantage of distracted clients to reduce their service quality. To more fully understand the importance of these findings for conservation and management, further studies should elucidate whether the efficacy of ectoparasite removal by cleaners is affected and explore the potential for habituation to boat noise in busy areas

Validation of a Fecal Glucocorticoid Assay to Assess Adrenocortical Activity in Meerkats Using Physiological and Biological Stimuli

In mammals, glucocorticoid (i.e. GC) levels have been associated with specific life-history stages and transitions, reproductive strategies, and a plethora of behaviors. Assessment of adrenocortical activity via measurement of glucocorticoid metabolites in feces (FGCM) has greatly facilitated data collection from wild animals, due to its non-invasive nature, and thus has become an established tool in behavioral ecology and conservation biology. The aim of our study was to validate a fecal glucocorticoid assay for assessing adrenocortical activity in meerkats (Suricata suricatta), by comparing the suitability of three GC enzyme immunoassays (corticosterone, 11β-hydroxyetiocholanolone and 11oxo-etiocholanolone) in detecting FGCM increases in adult males and females following a pharmacological challenge with adrenocorticotropic hormone (ACTH) and biological stimuli. In addition, we investigated the time course characterizing FGCM excretion, the effect of age, sex and time of day on FGCM levels and assessed the potential effects of soil contamination (sand) on FGCM patterns. Our results show that the group specific 11β-hydroxyetiocholanolone assay was most sensitive to FGCM alterations, detecting significant and most distinctive elevations in FGCM levels around 25 h after ACTH administration. We found no age and sex differences in basal FGCM or on peak response levels to ACTH, but a marked diurnal pattern, with FGCM levels being substantially higher in the morning than later during the day. Soil contamination did not significantly affect FGCM patterns. Our results emphasize the importance of conducting assay validations to characterize species-specific endocrine excretion patterns, a crucial step to all animal endocrinology studies using a non-invasive approach.peerReviewe