Good or bad vibrations? Impacts of anthropogenic vibration on the marine epibenthos

Characteristic noise of offshore wind turbine impacts the behavior and muscle physiology of sea cucumber Apostichopus japonicus

Sea cucumbers plays a crucial role in maintaining ecological balance through their unique behaviors and physiological functions. However, the noise from offshore wind turbines disrupts the habitat environment of the sea cucumber, potentially altering their behavior and physiology. Nevertheless, limited research exists on how noise from offshore wind turbines affects the sea cucumbers. In our study, we explored the effects of specific wind turbine noise frequencies on the behavior and muscle metabolism of sea cucumbers through four experimental groups: control, 125 Hz, 250 Hz, and 2500 Hz. Statistical analysis of the sea cucumber's ingestion rate, fecal production rate, step frequency and total step length showed that low-frequency noise (125 Hz and 250 Hz) significantly enhanced their locomotion and feeding activity compared to the control group. Further examination demonstrated that low-frequency noise significantly changed the metabolic products in sea cucumber's muscles, altering levels of nine metabolites, excluding tetraazecyclododecane tetraacetic acid. Furthermore, four key metabolic pathways showed marked alterations: pantothenate and CoA biosynthesis, glycerophospholipid metabolism, pyrimidine metabolism, and purine metabolism. These findings demonstrate that sea cucumbers adapt behaviorally and metabolically to anthropogenic noise disturbances.

Exploring offshore particle motion soundscapes

Fishes and aquatic invertebrates utilize acoustic particle motion for hearing, and some additionally detect sound pressure. Yet, few underwater soundscapes studies report particle motion, which is often assumed to scale predictably with pressure in offshore habitats. This relationship does not always exist for low frequencies or near reflective boundaries. This study compared particle motion and sound pressure from hydrophone arrays near the seafloor at six sites on the U.S. Mid and South Atlantic Outer Continental Shelf and assessed predictability of sound pressure and particle motion levels by environmental indicators (wind, vessels, temperature, currents). Unidentified fish sounds (100-750 Hz) had particle motion magnitudes 4.8-12.6 dB greater than those predicted from single hydrophone (pressure) measurements, indicating that these sounds were received in the near field. Excess particle motion attributed to hydrodynamic flow noise (<100 Hz) was also present at all sites. Most sounds (25th-75th percentile) from other sources received in the far field (vessels, mammals), had measured particle motion within ±3 dB of that predicted from single hydrophone measurements. The results emphasize for offshore soundscapes the importance of particle motion measurement for short-time (1 min) and near field signals, and that pressure measurement is sufficient for long-term (1 year) predictive modeling.

Marine and Freshwater Sounds Impact Invertebrate Behavior and Physiology: A Meta-Analysis

The diversity of biotic and abiotic sounds that fill underwater ecosystems has become polluted by anthropogenic noise in recent decades. Yet, there is still great uncertainty surrounding how different acoustic stimuli influence marine and freshwater (i.e., aquatic) communities. Despite capabilities to detect and produce sounds, aquatic invertebrates are among the most understudied taxa within the field of soundscape ecology. We conducted a meta-analysis to understand how sounds from various sources influence the behavior and physiology of aquatic invertebrates. We extracted 835 data points from 46 studies conducted in 15 countries. The resulting data included 50 species, a range of experimental conditions, and four sound categories: anthropogenic, environmental, synthetic, and music. We used meta-analytic multivariate mixed-effect models to determine how each sound category influenced aquatic invertebrates and if responses were homogeneous across taxa. Our analyses illustrate that anthropogenic noise and synthetic sounds have detrimental impacts on aquatic invertebrate behavior and physiology, and that environmental sounds have slightly beneficial effects on their behavior. Defence responses were the most impacted behaviors, while the most prominent physiological responses were related to biochemistry, genetics, and morphology. Additionally, arthropods and molluscs exhibited the most pronounced physiological responses to anthropogenic and synthetic noise. These findings support the conclusion that many invertebrate species are sensitive to changes in aquatic soundscapes, which can cause adverse or favorable consequences to individuals and populations, dependent on the sound source. This quantitative synthesis highlights the necessity of including marine and freshwater invertebrates in acoustic exposure studies, aquatic ecosystem assessments, and emerging noise pollution policies.

Comprehensive analysis of the seismic wave fields generated by offshore pile driving: A case study at the BARD Offshore 1 offshore wind farm

Offshore pile driving not only generates high sound pressure levels, but also induces ground vibrations and particle motions that have the potential to affect fish and invertebrates living near or in the seabed. In particular, the seismic wave field in the form of interface waves is thought to be responsible for causing these particle motions and ground vibrations. However, the magnitude and spatial extent of the seismic wave field resulting from pile driving has not been clearly established. To fill this knowledge gap, this paper analyzes and illustrates in detail the seismic wave field at a construction site of the BARD Offshore 1 wind farm. For this purpose, the measured data from the construction site are compared to the results of a seismo-acoustic model. The measured and modeled data in combination provides a potential benchmark case for subsequent studies and other authors. The computed seismic wave field is investigated in terms of wave generation, mode composition, and propagation range of individual modes. The different seismic wave forms and their contribution to the particle motions in the seabed vicinity are discussed. The results indicate that, for the considered case, interface waves dominate the particle motion at the seafloor level up to a distance of 200 m.

The effect of anthropogenic substrate-borne vibrations on locomotion of the fiddler crab Austruca lactea

The anthropogenic construction activities on the coasts, such as pile-driving, generate vibrations that propagate through the substrate. Such substrate-borne vibrations could potentially affect marine organisms inhabiting the benthic environments. However, there is a lack of documented studies on the effects of vibrations on benthic animals. To investigate whether anthropogenic substrate-borne vibrations such as pile-driving operation influence the fiddler crab, Austruca lactea, we measured their locomotion response under vibrations of 35, 120, 250, 500, and 750 Hz generated by a vibrator. We compared the locomotion of crabs between control and vibration-treatment groups using videography. The duration of movements was significantly lower under 120 Hz vibrations compared to the control. Moreover, crab velocity was significantly higher under vibrations of 120 Hz and 250 Hz compared to the control group. Our result suggests that A. lactea can detect low-frequency substrate-borne vibrations and experience stress, leading to increased energy consumption.

Anthropogenic underwater noise: A review on physiological and molecular responses of marine biota

The detrimental effects of anthropogenic underwater noise on marine organisms have garnered significant attention among scientists. This review delves into the research concerning the repercussions of underwater noise on marine species, with specific emphasis on the physiological and molecular responses of marine biota. This review investigates the sensory mechanisms, hearing sensitivity, and reaction thresholds of diverse marine organisms, shedding light on their susceptibility to underwater noise disturbances. The physiological and molecular effects of anthropogenic underwater noise on marine biota include oxidative stress, energy homeostasis, metabolism, immune function, and respiration. Additionally, changes in the gene expression profile associated with oxidative stress, metabolism, and immunological response are among the responses reported for marine biota. These effects pose a threat to animal fitness and potentially affect their survival as individuals and populations.

Transcriptomic analysis reveals the immune response mechanisms of sea cucumber Apostichopus japonicus under noise stress from offshore wind turbine

As an important form of renewable energy, offshore wind power can effectively reduce dependence on traditional energy sources and decrease carbon emissions. However, operation of wind turbines can generate underwater noise that may have negative impacts on marine benthic organisms in the surrounding area. Sea cucumbers are slow-moving invertebrates that inhabit the ocean, relying on their immune system to adapt to their environment. To evaluate the frequency range of characteristic noise produced by offshore wind turbines, we conducted a field survey. Additionally, we utilized sea cucumbers in simulated experiments to assess their response to the noise produced by offshore wind turbines. We established a control group, a low-frequency noise group simulating offshore wind turbine noise at 125 Hz and 250 Hz, and a high-frequency noise group at 2500 Hz, each lasting for 7 days. Results from measuring immune enzyme activity in the coelomic fluid suggest that noise can reduce the activity of superoxide dismutase enzymes, which may make sea cucumbers more susceptible to oxidative damage caused by free radicals. Exposure to low-frequency noise can have the effect of diminishing the activity of catalase, and this decrease in catalase activity could potentially increase the susceptibility of the sea cucumber's coelom to inflammation. In order to elucidate the hypothetical mechanism of immune response, intestinal tissue was extracted for transcriptome sequencing. The results showed that under 125 Hz low-frequency noise stress, the number of differentially expressed genes was the highest, reaching 1764. Under noise stress, sea cucumber's cell apoptosis and cell motility are reduced, interfering with lipid metabolism process and membrane synthesis. This research provides theoretical support for the environmental safety assessment of offshore wind power construction.

Vibrational and acoustic communication in fishes: The overlooked overlap between the underwater vibroscape and soundscape

Substrate-borne communication via mechanical waves is widespread throughout the animal kingdom but has not been intensively studied in fishes. Families such as the salmonids and sculpins have been documented to produce vibratory signals. However, it is likely that fish taxa on or close to the substrate that produce acoustic signals will also have a vibratory component to their signal due to their proximity to substrates and energy transfer between media. Fishes present an intriguing opportunity to study vibrational communication, particularly in the context of signal production and detection, detection range, and how vibratory signals may complement or replace acoustic signals. It is highly likely that the vibrational landscape, the vibroscape, is an important component of their sensory world, which certainly includes and overlaps with the soundscape. With the wide range of anthropogenic activities modifying underwater substrates, vibrational noise presents similar risks as acoustic noise pollution for fishes that depend on vibrational communication. However, in order to understand vibrational noise, more empirical studies are required to investigate the role of vibrations in the fish environment.

Sound and sturgeon: Bioacoustics and anthropogenic sounda)

Sturgeons are basal bony fishes, most species of which are considered threatened and/or endangered. Like all fishes, sturgeons use hearing to learn about their environment and perhaps communicate with conspecifics, as in mating. Thus, anything that impacts the ability of sturgeon to hear biologically important sounds could impact fitness and survival of individuals and populations. There is growing concern that the sounds produced by human activities (anthropogenic sound), such as from shipping, commercial barge navigation on rivers, offshore windfarms, and oil and gas exploration, could impact hearing by aquatic organisms. Thus, it is critical to understand how sturgeon hear, what they hear, and how they use sound. Such data are needed to set regulatory criteria for anthropogenic sound to protect these animals. However, very little is known about sturgeon behavioral responses to sound and their use of sound. To help understand the issues related to sturgeon and anthropogenic sound, this review first examines what is known about sturgeon bioacoustics. It then considers the potential effects of anthropogenic sound on sturgeon and, finally identifies areas of research that could substantially improve knowledge of sturgeon bioacoustics and effects of anthropogenic sound. Filling these gaps will help regulators establish appropriate protection for sturgeon.

Daytime boat sound does not affect the behavior of wild thorny oysters (Spondylus americanus): A field-based study

There is increasing awareness of boat sound effects on coral reef assemblages. While behavioral disturbances have been found in fishes, the effects on marine invertebrates remain largely unknown. Here, the behavioral effects of recreational boat sound on thorny oysters at two coral reef habitats within the U.S. Virgin Island National Park were assessed. The "treatment" site was characterized by frequent boat traffic, which increased daytime mean particle acceleration levels (PALrms) by more than 6 dB, while mean PALrms at the "control" site were not contaminated by boat sound. Despite these contrasting soundscapes, all oysters showed the same diurnal cycle, with their valves open at night and partially closed during the day. There was no statistical evidence of behavioral responses in oysters exposed to daytime boat sound. This can be explained by low auditory sensitivity, habituation to a noisy environment due to the pervasiveness of boat sound pollution, or that boat sound may not represent an immediate concern for this species. These findings contrast with laboratory studies that have shown behavioral responses in bivalves exposed to boat sound, highlighting the need for more realistic field-based studies when evaluating potential effects of anthropogenic sounds on this group.

Sound sensitivity of the giant scallop (Placopecten magelanicus) is life stage, intensity, and frequency dependent

There is increasing concern that anthropogenic sounds have a significant impact on marine animals, but there remains insufficient data on sound sensitivities for most invertebrates, despite their ecological and economic importance. We quantified auditory thresholds (in particle acceleration levels) and bandwidth of the giant scallop (Placopecten magellanicus) and subsequently sought to discern sensitivity among two different life stages: juveniles (1 yr olds) and subadults (3 yr olds). We also leveraged a novel valvometry technique to quantify the amplitude of scallop valve gape reductions when exposed to different sound amplitudes and frequencies. Behavioral responses were obtained for lower frequencies below 500 Hz, with best sensitivity at 100 Hz. There were significant differences between the auditory thresholds of juveniles and subadults, with juveniles being more sensitive, suggesting ontogenetic differences in hearing sensitivity. Scallops showed intensity and frequency dependent responses to sounds, with higher valve closures to lower frequencies and higher sound levels. To our knowledge, these are the first data highlighting life stage, intensity, and frequency responses to sound in a marine benthic invertebrate. These results demonstrate clear sound sensitivity and underscore that the potential impacts of anthropogenic sound in valuable ecological resources, such as scallops, may be dependent on sound characteristics.

Pile driving repeatedly impacts the giant scallop (Placopecten magellanicus)

Large-scale offshore wind farms are a critical component of the worldwide climate strategy. However, their developments have been opposed by the fishing industry because of concerns regarding the impacts of pile driving vibrations during constructions on commercially important marine invertebrates, including bivalves. Using field-based daily exposure, we showed that pile driving induced repeated valve closures in different scallop life stages, with particularly stronger effects for juveniles. Scallops showed no acclimatization to repetitive pile driving across and within days, yet quickly returned to their initial behavioral baselines after vibration-cessation. While vibration sensitivity was consistent, daily pile driving did not disrupt scallop circadian rhythm, but suggests serious impacts at night when valve openings are greater. Overall, our results show distance and temporal patterns can support future mitigation strategies but also highlight concerns regarding the larger impact ranges of impending widespread offshore wind farm constructions on scallop populations.

The Sound World of Zebrafish: A Critical Review of Hearing Assessment

Zebrafish, like all fish species, use sound to learn about their environment. Thus, human-generated (anthropogenic) sound added to the environment has the potential to disrupt the detection of biologically relevant sounds, alter behavior, impact fitness, and produce stress and other effects that can alter the well-being of animals. This review considers the bioacoustics of zebrafish in the laboratory with two goals. First, we discuss zebrafish hearing and the problems and issues that must be considered in any studies to get a clear understanding of hearing capabilities. Second, we focus on the potential effects of sounds in the tank environment and its impact on zebrafish physiology and health. To do this, we discuss underwater acoustics and the very specialized acoustics of fish tanks, in which zebrafish live and are studied. We consider what is known about zebrafish hearing and what is known about the potential impacts of tank acoustics on zebrafish and their well-being. We conclude with suggestions regarding the major gaps in what is known about zebrafish hearing as well as questions that must be explored to better understand how well zebrafish tolerate and deal with the acoustic world they live in within laboratories.

Is It Time for Ecotremology?

Our awareness of air-borne sounds in natural and urban habitats has led to the recent recognition of soundscape ecology and ecoacoustics as interdisciplinary fields of research that can help us better understand ecological processes and ecosystem dynamics. Because the vibroscape (i.e., the substrate-borne vibrations occurring in a given environment) is hidden to the human senses, we have largely overlooked its ecological significance. Substrate vibrations provide information crucial to the reproduction and survival of most animals, especially arthropods, which are essential to ecosystem functioning. Thus, vibroscape is an important component of the environment perceived by the majority of animals. Nowadays, when the environment is rapidly changing due to human activities, climate change, and invasive species, this hidden vibratory world is also likely to change without our notice, with potentially crucial effects on arthropod communities. Here, we introduce ecotremology, a discipline that mainly aims at studying substrate-borne vibrations for unraveling ecological processes and biological conservation. As biotremology follows the main research concepts of bioacoustics, ecotremology is consistent with the paradigms of ecoacoustics. We argue that information extracted from substrate vibrations present in the environment can be used to comprehensively assess and reliably predict ecosystem changes. We identify key research questions and discuss the technical challenges associated with ecotremology studies.

Recent progress in marine noise pollution: A thorough review

The increase in urbanization and the progressive development of marine industries have led to the appearance of a new kind of pollution called "noise pollution". This pollution exerts an increasing pressure on marine mammals, fish species, and invertebrates, which constitutes a new debate that must be controlled in a sustainable way by environmental and noise approaches with the objective of preserving marine and human life. Despite, noise pollution can travel long distances underwater, cover large areas, and have secondary effects on marine animals; by masking their ability to hear their prey or predators, finding their way, or connecting group members. During the COVID-19 pandemic, except for the transportation of essential goods and emergency services, all the public transport services were suspended including aircraft and ships. This lockdown has impacted positively on the marine environment through reduction of the noise sources. In this article, we are interested in noise pollution in general, its sources, impacts, and the management and future actions to follow. And since this pollution is not studied in Morocco, we focused on the different sources that can generate it on the Moroccan coasts. This is the first review article, which focuses on the impact of the COVID 19 pandemic on this type of pollution in the marine environment; which we aim to identify the impact of this pandemic on underwater noise and marine species. Finally, and given the increase in noise levels, preventive management, both at the national and international level, is required before irreversible damage is caused to biodiversity and the marine ecosystem.

Potential impacts from simulated vessel noise and sonar on commercially important invertebrates

Human usage of coastal water bodies continues to increase and many invertebrates face a broad suite of anthropogenic stressors (e.g., warming, pollution, acidification, fishing pressure). Underwater sound is a stressor that continues to increase in coastal areas, but the potential impact on invertebrates is not well understood. In addition to masking natural sound cues which may be important for behavioral interactions, there is a small but increasing body of scientific literature indicating sublethal physiological stress may occur in invertebrates exposed to high levels of underwater sound, particularly low frequency sounds such as vessel traffic, construction noise, and some types of sonar. Juvenile and sub-adult blue crabs (Callinectes sapidus) and American lobsters (Homarus americanus) were exposed to simulated low-frequency vessel noise (a signal was low-pass filtered below 1 kHz to ensure low-frequency content only) and mid-frequency sonar (a 1-s 1.67 kHz continuous wave pulse followed by a 2.5 to 4.0 kHz 1-s linear frequency modulated chirp) and behavioral response (the animal's activity level) was quantified during and after exposure using EthoVision XT™ from overhead video recordings. Source noise was quantified by particle acceleration and pressure. Physiological response to the insults (stress and recovery) were also quantified by measuring changes in hemolymph heat shock protein (HSP27) and glucose over 7 days post-exposure. In general, physiological indicators returned to baseline levels within approximately 48 h, and no observable difference in mortality between treatment and control animals was detected. However, there was a consistent amplified hemolymph glucose signal present 7 days after exposure for those animals exposed to mid-frequency sound and there were changes to C. sapidus competitive behavior within 24 h of exposure to sound. These results stress the importance of considering the impacts of underwater sound among the suite of stressors facing marine and estuarine invertebrates, and in the discussion of management actions such as protected areas, impact assessments, and marine spatial planning efforts.

Offshore wind energy development: Research priorities for sound and vibration effects on fishes and aquatic invertebrates

There are substantial knowledge gaps regarding both the bioacoustics and the responses of animals to sounds associated with pre-construction, construction, and operations of offshore wind (OSW) energy development. A workgroup of the 2020 State of the Science Workshop on Wildlife and Offshore Wind Energy identified studies for the next five years to help stakeholders better understand potential cumulative biological impacts of sound and vibration to fishes and aquatic invertebrates as the OSW industry develops. The workgroup identified seven short-term priorities that include a mix of primary research and coordination efforts. Key research needs include the examination of animal displacement and other behavioral responses to sound, as well as hearing sensitivity studies related to particle motion, substrate vibration, and sound pressure. Other needs include: identification of priority taxa on which to focus research; standardization of methods; development of a long-term highly instrumented field site; and examination of sound mitigation options for fishes and aquatic invertebrates. Effective assessment of potential cumulative impacts of sound and vibration on fishes and aquatic invertebrates is currently precluded by these and other knowledge gaps. However, filling critical gaps in knowledge will improve our understanding of possible sound-related impacts of OSW energy development to populations and ecosystems.

Noisy waters can influence young-of-year lobsters' substrate choice and their antipredatory responses

Offshore human activities lead to increasing amounts of underwater noise in coastal and shelf environments, which may affect commercially-important benthic invertebrate groups like the re-stocked Helgoland European lobster (Homarus gammarus) in the German Bight (North Sea). It is crucial to understand the impact tonal low-frequency noises, like maritime transport and offshore energy operations, may have on substrate choice and lobsters' behavior to assess potential benefits or bottlenecks of new hard-substrate artificial offshore environments that become available. In this study, we investigated the full factorial effect of a tonal low-frequency noise and predator presence on young-of-year (YOY) European lobsters' in a diurnal and nocturnal experiment. Rocks and European oyster shells (Ostrea edulis) were offered as substrate to YOY lobsters for 3 h. Video recordings (n = 134) allowed the identification of lobsters' initial substrate choice, diel activity and key behaviors (peeking, shelter construction, exploration and hiding). To ensure independence, YOY lobsters in the intermolt stage were randomly selected and assigned to the experimental tanks and used only once. We provide the first evidence that stressors alone, and in combination, constrain YOY lobsters' initial substrate choice towards rocks. During nighttime, the joint effect of exposure to a constant low-frequency noise and predator presence decreased antipredator behavior (i.e., hiding) and increased exploration behavior. Noise may thus interfere with YOY lobsters' attention and decision-making processes. This outcome pinpoints that added tonal low-frequency noise in the environment have the potential to influence the behavior of early-life stages of European lobsters under predator pressure and highlights the importance of including key benthic invertebrates' community relationships in anthropogenic noise risk assessments. Among others, effects of noise must be taken into consideration in plans involving the multi-use of any offshore area for decapods' stock enhancement, aquaculture, and temporary no-take zones.

Comparative sound detection abilities of four decapod crustaceans

Sound perception and detection in decapod crustaceans is surprisingly poorly understood, even though there is mounting evidence for sound playing a critical role in many life history strategies. The suspected primary organ of sound perception are the paired statocysts at the base of the first antennal segment. To better understand the comparative sound detection of decapods, auditory evoked potentials were recorded from the statocyst nerve region of four species (Leptograpsus variegate, Plagusia chabrus, Ovalipes catharus, Austrohelice crassa) in response to two different auditory stimuli presentation methods, shaker table (particle acceleration) and underwater speaker (particle acceleration and pressure). The results showed that there was significant variation in the sound detection abilities between all four species. However, exposure to the speaker stimuli increased all four species sound detection abilities, both in terms of frequency bandwidth and sensitivity, compared to shaker table derived sound detection abilities. This indicates that there is another sensory mechanism in play as well as the statocyst system. Overall, the present research provides comparative evidence of sound detection in decapods and indicates underwater sound detection in this animal group was even more complex than previously thought.

The role of auditory and vibration stimuli in zebrafish neurobehavioral models

Strongly affecting human and animal physiology, sounds and vibration are critical environmental factors whose complex role in behavioral and brain functions necessitates further clinical and experimental studies. Zebrafish are a promising model organism for neuroscience research, including probing the contribution of auditory and vibration stimuli to neurobehavioral processes. Here, we summarize mounting evidence on the role of sound and vibration in zebrafish behavior and brain function, and outline future directions of translational research in this field. With the growing environmental exposure to noise and vibration, we call for more active use of zebrafish models for probing neurobehavioral and bioenvironmental consequences of acute and long-term exposure to sounds and vibration in complex biological systems.

Anthropogenic underwater vibrations are sensed and stressful for the shore crab Carcinus maenas

Acoustic pollution in aquatic environments has increased with adverse effects on many aquatic organisms. However, little work has been done considering the effects of the vibratory component of acoustic stimuli, which can be transmitted in the substrate and propagated into the aquatic medium. Benthic marine organisms, including many invertebrates, are capable of sensing seabed vibration, yet the responses they trigger on organism have received little attention. This study investigates the impact of underwater vibration on the physiology and behaviour of a ubiquitous inhabitant of coastal areas of the northern hemisphere, the shore crab Carcinus maenas. We developed a novel vibratory apparatus with geophones supported on a softly sprung frame to induce a seabed vibration of 20 Hz frequency, as observed during dredging, piling and other anthropogenic activities. The geophone internal mass caused the frame to vibrate in a controlled manner. Our results show that transition from ambient to anthropogenic vibrations induced an increase in activity and antennae beats in shore crabs, indicating perception of the vibratory stimulus and a higher stress level. There was also a trend on sex-specific responses to anthropogenic vibration, with males showing a higher activity level than females. However, no effect of anthropogenic vibrations was found upon oxygen consumption. These results show that anthropogenic underwater vibration induces behavioural responses in Carcinus maenas. This highlights the importance of evaluating man-made vibratory activities on coastal invertebrates and the necessity of evaluating anthropogenic effects on both sexes.

North Sea soundscapes from a fish perspective: Directional patterns in particle motion and masking potential from anthropogenic noise

The aquatic world of animals is an acoustic world as sound is the most prominent sensory capacity to extract information about the environment for many aquatic species. Fish can hear particle motion, and a swim bladder potentially adds the additional capacity to sense sound pressure. Combining these capacities allows them to sense direction, distance, spectral content, and detailed temporal patterns. Both sound pressure and particle motion were recorded in a shallow part of the North Sea before and during exposure to a full-scale airgun array from an experimental seismic survey. Distinct amplitude fluctuations and directional patterns in the ambient noise were found to be fluctuating in phase with the tidal cycles and coming from distinct directions. It was speculated that the patterns may be determined by distant sources associated with large rivers and nearby beaches. Sounds of the experimental seismic survey were above the ambient conditions for particle acceleration up to 10 km from the source, at least as detectable for the measurement device, and up to 31 km for the sound pressure. These results and discussion provide a fresh perspective on the auditory world of fishes and a shift in the understanding about potential ranges over which they may have access to biologically relevant cues and be masked by anthropogenic noise.

Substrate vibrations and their potential effects upon fishes and invertebrates

This paper reviews the nature of substrate vibration within aquatic environments where seismic interface waves may travel along the surface of the substrate, generating high levels of particle motion. There are, however, few data on the ambient levels of particle motion close to the seabed and within the substrates of lakes and rivers. Nor is there information on the levels and the characteristics of the particle motion generated by anthropogenic sources in and on the substrate, which may have major effects upon fishes and invertebrates, all of which primarily detect particle motion. We therefore consider how to monitor substrate vibration and describe the information gained from modeling it. Unlike most acoustic modeling, we treat the substrate as a solid. Furthermore, we use a model where the substrate stiffness increases with depth but makes use of a wave that propagates with little or no dispersion. This shows the presence of higher levels of particle motion than those predicted from the acoustic pressures, and we consider the possible effects of substrate vibration upon fishes and invertebrates. We suggest that research is needed to examine the actual nature of substrate vibration and its effects upon aquatic animals.

Changes in feeding behavior of longfin squid (Doryteuthis pealeii) during laboratory exposure to pile driving noise

Anthropogenic noise can cause diverse changes in animals' behaviors, but effects on feeding behaviors are understudied, especially for key invertebrate taxa. With the offshore wind industry expanding, concern exists regarding potential impacts of pile driving noise on squid and other commercially and ecologically vital taxa. We investigated changes in feeding and alarm (defense) behaviors of squid, Doryteuthis pealeii, predating on killifish, Fundulus heteroclitus, during playbacks of pile driving noise recorded from wind farm construction within squids' habitat. Fewer squid captured killifish during noise exposure compared to controls. Squid had more failed predation attempts when noise was started during predation sequences. Alarm responses to noise were similar whether or not squid were hunting killifish, indicating similar vigilance to threat stimuli in these contexts. Additionally, novel hearing measurements on F. heteroclitus confirmed they could detect the noise. These results indicate noise can disrupt feeding behaviors of a key invertebrate species, and will leverage future studies on how noise may disrupt squids' vital ecological interactions.

Use of Ecoacoustics to Characterize the Marine Acoustic Environment off the North Atlantic French Saint-Pierre-et-Miquelon Archipelago

Visual observations of the marine biodiversity can be difficult in specific areas for different reasons, including weather conditions or a lack of observers. In such conditions, passive acoustics represents a potential alternative approach. The objective of this work is to demonstrate how information about marine biodiversity can be obtained via detailed analysis of the underwater acoustic environment. This paper presents the first analysis of the Saint-Pierre-and-Miquelon (SPM) archipelago underwater acoustic environment. In order to have a better knowledge about the marine biodiversity of SPM, acoustic recordings were sampled at different time periods to highlight seasonal variations over several years. To extract information from these acoustic recordings, standard soundscape and ecoacoustic analysis workflow was used to compute acoustic metrics such as power spectral density, third-octave levels, acoustic complexity index, and sound pressure levels. The SPM marine acoustic environment can be divided into three main sound source classes: biophony, anthrophony, and geophony. Several cetacean species were encountered in the audio recordings including sperm whales (which were detected by visual observations and strandings of 3 males in 2014), humpback, and blue whales.

Anthropogenic noise and biological sounds in a heavily industrialized coastal area (Gulf of Naples, Mediterranean Sea)

Underwater noise is one of the most widespread threats to the world oceans. Its negative impact on fauna is nowadays well established, but baseline data to be used in management and monitoring programs are still largely lacking. In particular, the acoustic assessment of human-impacted marine coastal areas provides complementary information on the health status of marine ecosystems. The objective of our study was to provide a baseline of underwater noise levels and biological sounds at two sites within the Gulf of Naples (Italy), one of which is located in Bagnoli-Coroglio, a Site of National Interest (SIN) for its high contamination levels. Within the SIN, sounds were recorded both before and during sediment coring activities (vibrocorer sampling), in order to investigate the potential acoustic impact due to such operations. Acoustic recordings were analyzed following the European Marine Strategy Framework Directive indications as defined in the frame of the Descriptor 11. Results reported here show that the investigated area is characterized by a high anthropogenic noise pressure. Ambient noise levels were principally driven by shipping noise and biological sounds of invertebrates (e.g., snapping shrimps). Sounds referable to other biological activity were difficult to detect because heavily masked by shipping noise. Coring activity determined a substantial introduction of additional noise at a local spatial scale. This study expands underwater noise baseline data to be further implemented in future monitoring programs of coastal areas affected by anthropogenic impacts. In addition, it proposes new cues for using underwater acoustic monitoring tools to complement traditional methodologies for evaluating health status of ecosystems and for investigating recovery rates after restoration/reclamation programs.

Impulsive pile driving noise elicits alarm responses in squid (Doryteuthis pealeii)

Pile driving occurs during construction of marine platforms, including offshore windfarms, producing intense sounds that can adversely affect marine animals. We quantified how a commercially and economically important squid (Doryteuthis pealeii: Lesueur 1821) responded to pile driving sounds recorded from a windfarm installation within this species' habitat. Fifteen-minute portions of these sounds were played to 16 individual squid. A subset of animals (n = 11) received a second exposure after a 24-h rest period. Body pattern changes, inking, jetting, and startle responses were observed and nearly all squid exhibited at least one response. These responses occurred primarily during the first 8 impulses and diminished quickly, indicating potential rapid, short-term habituation. Similar response rates were seen 24-h later, suggesting squid re-sensitized to the noise. Increased tolerance of anti-predatory alarm responses may alter squids' ability to deter and evade predators. Noise exposure may also disrupt normal intraspecific communication and ecologically relevant responses to sound.

Finding a home in the noise: cross-modal impact of anthropogenic vibration on animal search behaviour

Chemical cues and signals enable animals to sense their surroundings over vast distances and find key resources, like food and shelter. However, the use of chemosensory information may be impaired in aquatic habitats by anthropogenic activities, which produce both water-borne sounds and substrate-borne vibrations, potentially affecting not only vibroacoustic sensing but other modalities as well. We attracted marine hermit crabs (Pagurus acadianus) in field experiments using a chemical cue indicative of a newly available shell home. We then quantified the number of crabs arriving in control versus impulsive noise conditions. Treatment (control or noise), time (before or after), and the interaction between the two significantly affected the numbers of crabs, with fewer crabs attracted to the chemical cue after noise exposure. The results indicate that noise can affect chemical information use in the marine environment, acting cross-modally to impact chemically-guided search behaviour in free-ranging animals. Broadly, anthropogenic noise and seabed vibration may have profound effects, even on behaviours mediated by other sensory modalities. Hence, the impact of noise should be investigated not only within, but also across sensory modalities.

This article has an associated First Person interview with the first author of the paper.

Summary: Chemical cues enable animals to sense their surroundings and find key resources. Here we show that anthropogenic noise affects a chemically-guided search behaviour by acting cross-modally.

Are semi-terrestrial crabs threatened by human noise? Assessment of behavioural and biochemical responses of Neohelice granulata (Brachyura, Varunidae) in tank

This study examined the effects of human lab-generated noise (sweep tone) on the behaviour and biochemistry of a semi-terrestrial crab (Neohelice granulata). The experiment was carried out in tanks equipped with video- and audio-recording systems on a total of seventy-eight specimens. In total, 42 experimental trials with sweep-tone exposure and control conditions were performed using crabs in single and group layouts. After a habituation period of 30 min, the locomotor and acoustic (sound signals emitted by the crabs) behaviours were monitored for 30 min. During this time, the animals in sweep-tone conditions were exposed to ascending sweeps in a bandwidth range of 2.5-25 kHz. Exposure to sweep-tone noise produced significant changes in the number of signals emitted, locomotor behaviours and plasma parameters, such as haemolymph total haemocyte count and glucose, lactate and total protein concentrations, revealing that human noise could represent a disturbance for this crustacean species.

Assessing the impacts of seabed mineral extraction in the deep sea and coastal marine environments: Current methods and recommendations for environmental risk assessment

Mineral extraction from the seabed has experienced a recent surge of interest from both the mining industry and marine scientists. While improved methods of geological investigation have enabled the mapping of new seafloor mineral reserves, the ecological impacts of mining in both the deep sea and the shallow seabed are poorly known. This paper presents a synthesis of the empirical evidence from experimental seabed mining and parallel industries to infer the effects of seabed mineral extraction on marine ecosystems, focusing on polymetallic nodules and ferromanganese concretions. We use a problem-structuring framework to evaluate causal relationships between pressures caused by nodule extraction and the associated changes in marine ecosystems. To ensure that the rationale behind impact assessments is clear, we propose that future impact assessments use pressure-specific expert elicitation. We further discuss integrating ecosystem services in the impact assessments and the implications of current methods for environmental risk assessments.

Using best expert judgement to harmonise marine environmental status assessment and maritime spatial planning

All maritime states have the challenge of maintaining the environmental quality of their seas while at the same time maximising their economic potential thus requiring appropriate science, governance and management measures. In Europe, directives and regulations are used to address the pressures affecting the health and sustainability of marine resources, and to promote Good Environmental Status (GES) (e.g. the Marine Strategy Framework Directive, MSFD), while having a coherent and integrated pattern of sea use (e.g. the Maritime Spatial Planning Directive, MSPD). Therefore, an approach is required to meet these challenges for all maritime states including, for Europe, the joint adoption of these two directives. As such an approach does not yet exist, one is proposed here based on a hypothetical example and a Best Expert Judgement (BEJ) methodology. Forty-two marine science, management and impact assessment specialists provided views on a hypothetical marine scenario to derive and interrogate a framework applicable to marine areas with multiple uses and users. The scenario allowed the severity of the activity effects-footprints to be determined on the 11 MSFD Descriptors of GES with that severity being weighted according to the area of each activity effect-footprint. In turn, this allowed the calculation of marine regional environmental status thereby indicating whether the adoption of quality assessment and spatial planning can be mutually beneficial, or are antagonistic in meeting environmental targets. This paper uses the proposed approach to discuss maximising the assimilative capacity of a marine area and minimising the environmental degradation due to new activities. It especially shows the role of BEJ in cases where marine adaptive management is still required despite their being an often paucity of information or data on which to base management decisions.

The importance of particle motion to fishes and invertebrates

This paper considers the importance of particle motion to fishes and invertebrates and the steps that need to be taken to improve knowledge of its effects. It is aimed at scientists investigating the impacts of sounds on fishes and invertebrates but it is also relevant to regulators, those preparing environmental impact assessments, and to industries creating underwater sounds. The overall aim of this paper is to ensure that proper attention is paid to particle motion as a stimulus when evaluating the effects of sound upon aquatic life. Directions are suggested for future research and planning that, if implemented, will provide a better scientific basis for dealing with the impact of underwater sounds on marine ecosystems and for regulating those human activities that generate such sounds. The paper includes background material on underwater acoustics, focusing on particle motion; the importance of particle motion to fishes and invertebrates; and sound propagation through both water and the substrate. Consideration is then given to the data gaps that must be filled in order to better understand the interactions between particle motion and aquatic animals. Finally, suggestions are provided on how to increase the understanding of particle motion and its relevance to aquatic animals.