Acoustic monitoring and analyses of air gun, pile driving, vessel, and ambient sounds during the 2015 seismic surveys on the Sakhalin shelf.

During the summer of 2015, four 4D seismic surveys were conducted on the northeastern Sakhalin shelf near the feeding grounds of the Korean-Okhotsk (western) gray whale (Eschrichtius robustus) population. In addition to the seismic surveys, onshore pile driving activities and vessel operations occurred. Forty autonomous underwater acoustic recorders provided data in the 2 Hz to15 kHz frequency band. Recordings were analyzed to evaluate the characteristics of impulses propagating from the seismic sources. Acoustic metrics analyzed comprised peak sound pressure level (PK), mean square sound pressure level (SPL), sound exposure level (SEL), T100%, T90% (the time intervals that contain the full and 90% of the energy of the impulse), and kurtosis. The impulses analyzed differed significantly due to the variability and complexity of propagation in the shallow water of the northeast Sakhalin shelf. At larger ranges, a seismic precursor propagated in the seabed ahead of the acoustic impulse, and the impulses often interfered with each other, complicating analyses. Additional processing of recordings allowed evaluation and documentation of relevant metrics for pile driving, vessel sounds, and ambient background levels. The computed metrics were used to calibrate acoustic models, generating time resolved estimates of the acoustic levels from seismic surveys, pile driving, and vessel operations on a gray whale distribution grid and along observed gray whale tracks. This paper describes the development of the metrics and the calibrated acoustic models, both of which will be used in work quantifying gray whale behavioral and distribution responses to underwater sounds and to determine whether these observed responses have the potential to impact important parameters at the population level (e.g., reproductive success).

Ontogenetic variation in the auditory sensitivity of black sea bass (Centropristis striata) and the implications of anthropogenic sound on behavior and communication.

Black sea bass (Centropristis striata) is an important fish species in both commercial and recreational fisheries of southern New England and the mid-Atlantic Bight. Due to the intense urbanization of these waters, this species is subject to a wide range of anthropogenic noise pollution. Concerns that C. striata are negatively affected by pile driving and construction noise predominate in areas earmarked for energy development. However, as yet, the hearing range of C. striata is unknown, making it hard to evaluate potential risks. This study is a first step in understanding the effects of anthropogenic noise on C. striata by determining the auditory detection bandwidth and thresholds of this species using auditory evoked potentials, creating pressure and acceleration audiograms. These physiological tests were conducted on wild-caught C. striata in three size/age categories. Results showed that juvenile C. striata had the significantly lowest thresholds, with auditory sensitivity decreasing in the larger size classes. Furthermore, C.striata has fairly sensitive sound detection relative to other related species. Preliminary investigations into the mechanisms of their sound detection ability were undertaken with gross dissections and an opportunistic micro-computed tomography image to address the auditory structures including otoliths and swim bladder morphology. Crucially, the auditory detection bandwidth of C. striata, and their most sensitive frequencies, directly overlap with high-amplitude anthropogenic noise pollution such as shipping and underwater construction.

Test and Study of Pipe Pile Penetration in Cohesive Soil Using FBG Sensing Technology.

In order to examine the applicability of Fiber Bragg Grating (FBG) sensing technology in the static penetration of pipe piles, static penetration tests in clay were conducted using double-wall open and closed model pipe piles. The strain was measured using FBG sensors, and the plug height was measured using a cable displacement sensor. Using one open pile and two closed piles, the difference in pipe pile penetration was compared and analyzed. Based on FBG sensing technology and the strain data, the penetration characteristics of the pipe pile, such as axial force, lateral friction, and driving resistance were examined. Results showed that FBG sensing technology has superior testing performance for the pipe pile penetration process, can accurately reflect the strain time history of pipe piles, and can clearly reflect the penetration process of pipe piles with increasing penetration depth. In addition, the variation law of the characteristics of the jacked pile pile-soil interface was obtained. This test has significance for model tests and the engineering design of pipe piles.

Effects of impulsive noise on marine mammals: investigating range-dependent risk.

Concerns exist about the impacts of underwater noise on marine mammals. These include auditory damage, which is a significant risk for marine mammals exposed to impulsive sounds such as explosions, pile-driving, and seismic air guns. Currently, impact assessments use different risk criteria for impulsive and non-impulsive sounds (e.g., ships, drilling). However, as impulsive sounds dissipate through the environment, they potentially lose hazardous features (e.g., sudden onset) and become non-impulsive at some distance from the source. Despite management implications, a lack of data on range-dependent characteristics currently limits their inclusion in impact assessments. We address this using acoustic recordings of seismic air guns and pile-driving to quantify range dependency in impulsive characteristics using four criteria: (1) rise time < 25 ms; (2) quotient of peak pressure and pulse duration > 5,000 Pa/s; (3) duration < 1 s; (4) crest factor > 15 dB. We demonstrate that some characteristics changed markedly within ranges of ~10 km, and that the mean probability of exceeding criteria 1 and 2 was <0.5 at ranges >3.5 km. In contrast, the mean probability of exceeding criteria 3 remained >0.5 up to ~37.0 km, and the mean probability of exceeding criteria 4 remained <0.5 throughout the range. These results suggest that a proportion of the recorded signals should be defined as impulsive based on each of the criteria, and that some of the criteria change markedly as a result of propagation. However, the impulsive nature of a sound is likely to be a complex interaction of all these criteria, and many other unrelated parameters such as duty cycle, recovery periods, and sound levels will also strongly affect the risk of hearing damage. We recommend future auditory damage studies and impact assessments explicitly consider the ranges at which sounds may lose some of their potentially hazardous characteristics.

Anthropogenic noise pollution from pile-driving disrupts the structure and dynamics of fish shoals.

Noise produced from a variety of human activities can affect the physiology and behaviour of individual animals, but whether noise disrupts the social behaviour of animals is largely unknown. Animal groups such as flocks of birds or shoals of fish use simple interaction rules to coordinate their movements with near neighbours. In turn, this coordination allows individuals to gain the benefits of group living such as reduced predation risk and social information exchange. Noise could change how individuals interact in groups if noise is perceived as a threat, or if it masked, distracted or stressed individuals, and this could have impacts on the benefits of grouping. Here, we recorded trajectories of individual juvenile seabass (Dicentrarchus labrax) in groups under controlled laboratory conditions. Groups were exposed to playbacks of either ambient background sound recorded in their natural habitat, or playbacks of pile-driving, commonly used in marine construction. The pile-driving playback affected the structure and dynamics of the fish shoals significantly more than the ambient-sound playback. Compared to the ambient-sound playback, groups experiencing the pile-driving playback became less cohesive, less directionally ordered, and were less correlated in speed and directional changes. In effect, the additional-noise treatment disrupted the abilities of individuals to coordinate their movements with one another. Our work highlights the potential for noise pollution from pile-driving to disrupt the collective dynamics of fish shoals, which could have implications for the functional benefits of a group's collective behaviour.

Developing Sound Exposure Criteria for Fishes.

In assessing the impact of aquatic developments, it is important to evaluate whether accompanying underwater sounds might have adverse effects on fishes. Risk assessment can then be used to evaluate new and existing technologies for effective prevention, control, or mitigation of impacts. It is necessary to know the levels of sound that may cause potential harm to different species from different sources as well as those levels that are likely to be of no consequence. The development and use of impact criteria are still at an early stage for fishes.

Effects of Offshore Wind Farms on the Early Life Stages of Dicentrarchus labrax.

Anthropogenically generated underwater noise in the marine environment is ubiquitous, comprising both intense impulse and continuous noise. The installation of offshore wind farms across the North Sea has triggered a range of ecological questions regarding the impact of anthropogenically produced underwater noise on marine wildlife. Our interest is on the impact on the "passive drifters," i.e., the early life stages of fish that form the basis of fish populations and are an important prey for pelagic predators. This study deals with the impact of pile driving and operational noise generated at offshore wind farms on Dicentrarchus labrax (sea bass) larvae.

Residency of Reef Fish During Pile Driving Within a Shallow Pierside Environment.

The potential effects of pile driving on fish populations and commercial fisheries have received significant attention given the prevalence of construction occurring in coastal habitats throughout the world. In this study, we used acoustic telemetry to assess the movement and survival of free-ranging reef fish in Port Canaveral, FL, in response to 35 days of pile driving at an existing wharf complex. The site fidelity and behavior of 15 sheepshead (Archosargus probatocephalus) and 10 gray snapper (Lutjanus griseus) were determined before, during, and after pile driving. No obvious signs of mortality or injury to tagged fish were evident from the data. There was a significant decline in the residency index for mangrove snapper at the construction wharf after pile driving compared with the baseline, although this may be influenced by natural movements of this species in the study area rather than a direct response to pile driving.

A Change in the Use of Regulatory Criteria for Assessing Potential Impacts of Sound on Fishes.

The National Marine Fisheries Service (NMFS) currently uses interim criteria developed on the US West Coast to assess the potential onset of peak and cumulative effects of noise on fishes. Analyses performed for this project provided adequate support for the NMFS to use the peak criterion (i.e., area ensonified by 206 dB re 1 µPa peak sound pressure level [SPL(peak)]) for estimating the incidental take of Hudson River sturgeon. Application of the peak criterion (rather than the cumulative criterion) could have implications for future construction projects because estimates of take using SPL(peak) will generally be considerably lower than estimates of take based on the cumulative sound exposure level.

Pile Driving at the New Bridge at Tappan Zee: Potential Environmental Impacts.

A new bridge will be constructed to replace the aging Tappan Zee Bridge over the Hudson River in New York. Construction will potentially result in hydroacoustic impacts to the local fish fauna. As a consequence, a substantial environmental impact analysis had to be conducted to obtain construction permits. This paper describes the process of environmental analysis and some of the results of the studies that led up to the final permitting. The process included modeling of pile-driving acoustics, analysis of river ambient noise, analysis of test piling, and observations on fish behavior during these tests.

Underwater Sound Propagation from Marine Pile Driving.

Pile driving occurs in a variety of nearshore environments that typically have very shallow-water depths. The propagation of pile-driving sound in water is complex, where sound is directly radiated from the pile as well as through the ground substrate. Piles driven in the ground near water bodies can produce considerable underwater sound energy. This paper presents examples of sound propagation through shallow-water environments. Some of these examples illustrate the substantial variation in sound amplitude over time that can be critical to understand when computing an acoustic-based safety zone for aquatic species.

Acoustic Response to Playback of Pile-Driving Sounds by Snapping Shrimp.

There is concern about the effects of noise from impact pile driving as this constructional technique becomes increasingly widespread in coastal areas. The habitats of most marine invertebrate species are likely to overlap with the areas of human activities along the coast and be affected by the increased levels of noise produced. This paper investigates the acoustic response of chorusing snapping shrimp to different sound pressure levels. A significant increase in the snap number and snap amplitude was recorded during the playback of piling noise, suggesting that noise exposure affected the acoustic behavior of these animals.

Fulfilling EU Laws to Ensure Marine Mammal Protection During Marine Renewable Construction Operations in Scotland.

Large-scale offshore renewable energy infrastructure construction in Scottish waters is anticipated in coming decades. An approach being pursued, with a view to preventing short-range marine mammal injury, is the introduction of additional noise sources to intentionally disturb and displace animals from renewable sites over the construction period. To date, no full and transparent consideration has been given to the long-term cost benefits of noise reduction compared with noise-inducing mitigation techniques. It has yet to be determined if the introduction of additional noise is consistent with the objectives of the EU Habitats Directive and the Marine Strategy Framework Directive.

Cumulative Effects of Exposure to Continuous and Intermittent Sounds on Temporary Hearing Threshold Shifts Induced in a Harbor Porpoise (Phocoena phocoena).

The effects of exposure to continuous and intermittent anthropogenic sounds on temporary hearing threshold shifts (TTSs) in a harbor porpoise were investigated by testing hearing before and after exposure to 1- to 2-kHz downsweeps of 1 s, without harmonics, presented as paired-intermittent and continuous-exposure combinations with identical cumulative sound exposure levels (SEL(cum)). Exposure to intermittent sounds resulted in lower TTSs than exposure to continuous sounds with the same SEL(cum). Therefore, the hearing of marine mammals is at less risk from intermittent anthropogenic noises than from continuous ones at the same received sound pressure level and duration.

Noise Exposure Criteria for Harbor Porpoises.

Despite a major research effort, no generally accepted exposure limits are available for harbor porpoises. Recent studies of the temporary threshold shift (TTS) in porpoises indicate that the sound exposure levels (SELs) required to induce low levels of TTS depend on stimulus frequency and roughly parallel the shape of the audiogram. A number of studies on behavioral avoidance reactions (negative phonotaxis) to pingers, seal scarers, and pile driving show a similar dependence on stimulus frequency. Both TTS and behavioral data suggest that weighting sound pressure levels with a filter function resembling the inverted audiogram would be appropriate.

Noise pollution causes parental stress on marine invertebrates, the Giant scallop example.

In marine invertebrates, abiotic stresses on adults can act directly on gametes quality, which impacts phenotype and development success of the offspring. Human activities introduce noise pollution in the marine environment but still few studies on invertebrates have considered the impacts on adult or larval stages separately, and to our knowledge, never investigated the cross-generational effects of anthropogenic noise. This article explores parental effects of pile driving noise associated with the building phase of offshore wind turbines on a coastal invertebrate, Pecten maximus (L.). Adults were exposed to increasing levels of sound during gametogenesis, then their offspring were also exposed. The results highlight that anthropogenic noise experienced by the parents reduces their reproductive investment and modify larval response in similar conditions. Also, larvae from exposed adults grew 6-fold faster and metamorphosed 5-fold faster, which could be an amplified adaptive strategy to reduce the pelagic phase in a stressful environment.

Effects of exposure to pile driving sounds on fish inner ear tissues.

Impulsive pile driving sound can cause injury to fishes, but no studies to date have examined whether such injuries include damage to sensory hair cells in the ear. Possible effects on hair cells were tested using a specially designed wave tube to expose two species, hybrid striped bass (white bass Morone chrysops × striped bass Morone saxatilis) and Mozambique tilapia (Oreochromis mossambicus), to pile driving sounds. Fish were exposed to 960 pile driving strikes at one of three treatment levels: 216, 213, or 210dB re 1 µPa(2)·s cumulative Sound Exposure Level. Both hybrid striped bass and tilapia exhibited barotraumas such as swim bladder ruptures, herniations, and hematomas to several organs. Hybrid striped bass exposed to the highest sound level had significant numbers of damaged hair cells, while no damage was found when fish were exposed at lower sound levels. Considerable hair cell damage was found in only one out of 11 tilapia specimens exposed at the highest sound level. Results suggest that impulsive sounds such as from pile driving may have a more significant effect on the swim bladders and surrounding organs than on the inner ears of fishes, at least at the sound exposure levels used in this study.

Effects of pile driving sound on local movement of free-ranging Atlantic cod in the Belgian North Sea.

Offshore energy acquisition through the construction of wind farms is rapidly becoming one of the major sources of green energy all over the world. The construction of offshore wind farms contributes to the ocean soundscape as steel monopile foundations are commonly hammered into the seabed to anchor wind turbines. This pile driving activity causes repeated, impulsive, low-frequency sounds, reaching far into the environment, which may have an impact on the surrounding marine life. In this study, we investigated the effect of the construction of 50 wind turbine foundations, over a time span of four months, on the presence and movement behaviour of free-swimming, individually tagged Atlantic cod. The turbine foundations were constructed at a distance ranging between 2.3 and 7.1 km from the cod, which resided in a nearby, existing wind farm in the southern North Sea. Our results indicated that local fish remained in the exposed area during and in-between pile-driving activities, but showed some modest changes in movement patterns. The tagged cod did not increase their net movement activity, but moved closer to the scour-bed (i.e. hard substrate), surrounding their nearest turbine, during and after each piling event. Additionally, fish moved further away from the sound source, which was mainly due to the fact that they were positioned closer to a piling event before its start. We found no effect of the time since the last piling event. Long-term changes in movement behaviour can result in energy budget changes, and thereby in individual growth and maturation, eventually determining growth rate of populations. Consequently, although behavioural changes to pile driving in the current study seem modest, we believe that the potential for cumulative effects, and species-specific variation in impact, warrant more tagging studies in the future, with an emphasis on quantification of energy budgets.

Evaluation of pile driving accidents in geotechnical engineering.

Pile driving accidents that occurred between 1984 and 2018 were selected from the Occupational Safety and Health Administration database, producing 84 cases. To evaluate the causes of accidents, pile driving stages were presented and the potential hazards were discussed. Two models were necessary to link the accidents with workers' behavior. An accident type model and a workers' behavior model were developed. The accident type model was related to physical factors leading to accidents, and the workers' behavior model determined the occupational behavior under the act of the incident. Among fatal accidents, unsafe site conditions had the highest frequency at 26.9%. Among non-fatal accidents, both poor attitudes toward safety and unsafe methods had the highest frequency at 28.1%. Furthermore, a map presenting work-specific accident frequencies in pile driving operations was created. Consequently, project-specific countermeasures should be taken regarding the root causes of accidents, leading to vigorous strategies to develop safety measures.

Closure of spontaneous cerebrospinal fluid leakage via fistula at the lateral wall of the sphenoid sinus using a bone pile.

This report describes a case of spontaneous cerebrospinal fluid leak through a narrow canal-like fistula in the lateral wall of the sphenoid sinus, which was managed through rigid reconstruction. Rigid reconstruction of the skull base was performed by fitting a pile-shaped bone into the fistula like the pile-driving technique.