Alexander O MacGillivray

JASCO Research Ltd | JASCO

Investigation of sound pressure waveforms helps the selection of appropriate metrics to evaluate their effects on marine life in relation to noise thresholds. As marine animals move farther away from a sound source, the temporal characteristics of sound pressure may be influenced by interactions with the sediment and the sea surface. Sound pressure...

Models of the underwater acoustic soundscape are important for evaluating the effects of human generated sounds on marine life. The performance of models can be validated against measurements or verified against each other for consistency. A verification workshop was held to compare models that predict the soundscape from wind and vessels and estim...

Metrics to be used in noise impact assessment must integrate the physical acoustic characteristics of the sound field with relevant biology of animals. Several metrics have been established to determine and regulate underwater noise exposure to aquatic fauna. However, recent advances in understanding cause-effect relationships indicate that additio...

Evaluation of possible effects of underwater sound on aquatic life requires quantification of the sound field. A marine sound source and propagation modelling workshop took place in June 2022, whose objectives were to facilitate the evaluation of source and propagation models and to identify relevant metrics for environmental impact assessment. The...

This study presents the results of three-dimensional (3D) propagation modeling of noise from a transiting bulk carrier vessel. In the simulated scenario, the surface vessel is moving past a bottom-mounted hydrophone system. Sound levels are estimated in decidecade frequency bands as the vessel transits past the hydrophone, and the simulation result...

Against the backdrop of a steadily increasing demand for sea transport of goods and people, the development of a reliable marine shipping soundscape model is an essential planning requirement to assess the effect on ocean noise of operational and technological changes aimed at mitigating the environmental impact of the shipping sector. The NAVISON...

Modelling sound propagation over seabeds where the seabed cannot be approximated as an equivalent fluid due to limestone layers with high shear wave speeds is a common underwater acoustic propagation modelling problem for Australian shallow marine environments. With the increase in prospective areas for offshore windfarm development across Australi...

Vector acoustic properties of the underwater noise originating from impact pile driving on steel piles has been studied, including the identification of features of Mach wave radiation associated with the radial expansion of the pile upon hammer impact. The data originate from a 2005 study conducted in Puget Sound in the U.S. state of Washington, a...

Performing reproducible vessel source level (SL) measurements is complicated by seabed reflections in shallow water. In deep water, with a hydrophone far from the seabed, it is straightforward to estimate propagation loss (PL) and convert sound pressure level (SPL) into SL using the method codified in the international standard ISO 17208-2 [Interna...

Measurements of the source levels of 9880 passes of 3188 different large commercial ships from the Enhancing Cetacean Habitat and Observation (ECHO) program database were used to investigate the dependencies of vessel underwater noise emissions on several vessel design parameters and operating conditions. Trends in the dataset were analyzed using f...

No PDF available ABSTRACT Soundscape modeling is increasingly being used in assessments of marine habitat quality and to inform marine spatial planning. In most locations of interest, noise from shipping traffic and other marine vessels is the dominant anthropogenic contributor to the underwater soundscape. The noise contributions of marine vessels...

The habitat of the endangered southern resident killer whale (SRKW) overlaps major international shipping lanes near the Port of Vancouver, British Columbia. Shipping is a dominant source of underwater noise, which can hinder SRKW key life functions. To reduce environmental pressure on the SRKWs, Vancouver Fraser Port Authority offers incentives fo...

Please go to the DOI to access this open data set. This repository contains spatial data of modelled underwater noise levels at the benthic boundary layer due to vessel traffic in the Salish Sea. Received equivalent continuous noise levels (Leq) near the seabed were calculated using JASCO’s cumulative vessel noise model (Acoustic Real-Time Exposur...

The acoustical output of marine-seismic airguns is determined from recordings of the sound pressure made on hydrophones suspended below a floating barge from which the airguns are also deployed. The signals from multiple types of airguns are considered and each type is operated over a range of deployment depths and chamber pressures. The acoustical...

No PDF available ABSTRACT Launched in 2014, the Enhancing Cetacean Habitat and Observation (ECHO) Program, led by the Vancouver Fraser Port Authority, is a regional, collaborative program designed to better understand and reduce the cumulative effects from commercial shipping activities on at-risk whales. The program advances a number of research p...

No PDF available ABSTRACT Underwater noise from marine vessels can reduce the acoustic space that is available to marine mammals for performing critical life functions. Likewise, measures such as speed reductions that decrease vessel radiated noise can limit the extent to which acoustic space is affected by marine traffic. To investigate the benefi...

No PDF available ABSTRACT Underwater sound was modelled around the Port of Prince Rupert, British Columbia. The waters around the port region contain major international shipping lanes and important habitat for marine species, many of which require a quiet environment. Underwater noise calculations were carried out using JASCO's Acoustic Real-Time...

Underwater sound mapping is increasingly being used as a tool for monitoring and managing noise pollution from shipping in the marine environment. Sound maps typically rely on tracking data from the Automated Information System (AIS), but information available from AIS is limited and not easily related to vessel noise emissions. Thus, robust sound...

No PDF available ABSTRACT The Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat Observation (ECHO) program acquired a large database of several thousand systematic commercial ship noise measurements between September 2015 and April 2017. These measurements were used to develop a multi-variate linear regression model of vessel source leve...

No PDF available ABSTRACT Improving our knowledge of how sound impacts marine mammals is particularly important where the spatial distributions of vessels and marine mammals overlap, as exemplified by the critical habitat for the endangered Southern Resident Killer Whale (SRKW). In this study, two acoustic recorders were deployed in transboundary H...

No PDF available ABSTRACT Measurements from the large ship noise database acquired by the Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat Observation (ECHO) program were used to assess the conservativeness of five vessel noise certification societies. A multi-variate linear regression analysis of the database was used to scale ECHO mea...

The papers in this special issue focuses on the verification and validation of models for predicting the sound field radiated by air guns and air gun arrays. This issue aims to address the demand for increasingly precise assessments of environmental impacts, requiring accurate characterization of the air gun array sound field, including the interfa...

During 2017, the Vancouver Fraser Port Authority's Enhancing Cetacean Habitat and Observation program carried out a two-month voluntary vessel slowdown trial to determine whether slowing to 11 knots was an effective method for reducing underwater radiated vessel noise. The trial was carried out in Haro Strait, British Columbia, in critical habitat...

A voluntary commercial vessel slowdown trial was conducted through 16 nm of shipping lanes overlapping critical habitat of at-risk southern resident killer whales (SRKW) in the Salish Sea. From August 7 to October 6, 2017, the trial requested piloted vessels to slow to 11 knots speed-through-water. Analysis of AIS vessel tracking data showed that 3...

The Enhancing Cetacean Habitat and Observation (ECHO) Program, a collaborative program led by Vancouver Fraser Port Authority, coordinated voluntary slowdowns for commercial shipping traffic in Haro Strait in the summers of 2017 and 2018, to better understand the relationship between vessel speed and source level, and how this may effect noise leve...

The Vancouver Fraser Port Authority’s Enhancing Cetacean Habitat and Observation (ECHO) program sponsored deployment of two autonomous marine acoustic recorders (AMAR) in Haro Strait (BC), from July to October 2017, to measure sound levels produced by commercial vessels transiting the strait. Fisheries and Oceans Canada (DFO), a partner in ECHO, su...

Characterizing the source levels from seismic airgun arrays to increase confidence in model accuracy has been identified as a requirement by the scientific and regulatory community. To comply with regulatory requirements in Australia, a measurement program was conducted to validate the source signature predictions of JASCO’s Airgun Array Source Mod...

Commercial shipping routes pass through important habitat areas for several species of marine mammals in the coastal waterways of southern British Columbia. The Vancouver Fraser Port Authority, through its Enhancing Cetacean Habitat and Observation (ECHO) program, has undertaken studies to develop mitigation measures that will lead to a quantifiabl...

During 2017, the Vancouver Fraser Port Authority's Enhancing Cetacean Habitat and Observation (ECHO) program carried out a voluntary slowdown trial in Haro Strait (British Columbia) to investigate whether limiting vessel speeds to 11 knots would decrease noise in Southern Resident Killer Whale habitat. During the trial, JASCO collected source level...

This study assesses vessel-noise exposure levels for Southern Resident Killer Whales (SRKW) in the Salish Sea. Kernel Density Estimation (KDE) was used to delineate SRKW summer core areas. Those areas were combined with the output of a regional cumulative noise model describing sound level variations generated by commercial vessels (1/3-octave-band...

JASCO's Airgun Array Source Model (AASM) is a combined deterministic and stochastic model that separately treats the low-frequency and high-frequency components of signals produced by airgun arrays. The low-frequency module is based on solving the equations of motion for interacting spherical bubbles. The high-frequency module is based on a stochas...

Underwater noise from impact pile driving of 512 -m-long conductor casings was measured at a deep-water offshore oil platform in the Santa Barbara Channel. Beamforming measurements, obtained with a vertical array, confirmed that the primary wave front generated by hammering the conductor casing was a Mach cone propagating at an angle of 17.6° below...

Man-made ocean noise can cause physical injury and behavioral disturbance to marine life. It hampers marine mammals’ use of sound for foraging, communicating, navigating, socializing, and mating. Advancements in acoustic recorders, ocean observatories, vessel tracking, and noise modelling allow us to study and manage the effects of vessel noise on...

Underwater acousticmeasurements of pile driving operations were made at the Ketchikan ferry terminal in July 2016. At the time of the measurements, marine mammal injury and disturbance criteria developed by the National Marine Fisheries Service (NMFS) were based on sound pressure level (SPL) thresholds. Shortly after the measurements, NMFS changed...

Elevated ambient noise levels have been shown to affect marine fauna communication. The effects due to increased noise levels from the multipath propagation and reverberation of airgun pulses over large distances is a relatively new area of interest. This research examines a distant seismic survey opportunistically recorded at two locations during...

Elevated ambient noise levels have been shown to affect marine fauna communication. The effects due to increased noise levels from the multipath propagation and reverberation of airgun pulses over large distances is a relatively new area of interest. This research examines a distant seismic survey opportunistically recorded at two locations during...

The prediction of underwater noise emissions from impact pile driving during near-shore and offshore construction activities and its potential effect on the marine environment has been a major field of research for several years. A number of different modeling approaches have been suggested recently to predict the radiated sound pressure at differe...

It is a common practice for regulators to require project proponents to estimate the radius around a sound source where marine life could be injured or disturbed. Acoustic propagationmodeling is normally required so that realistic radii are obtained that take into account the bathymetry, bottom properties, water column sound velocity profile, as we...

The potential impact of seismic surveys on marine life has given regulators and scientists a shared interest in quantifying the sound field radiated by airgun arrays. Predictions do not always agree well with measurements, and there is a need to build confidence in model accuracy. To address this need, experts in airgun sound fieldmodeling were inv...

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 enviro...

The potential impacts of pile-driving noise on Hudson River sturgeon during construction of the New NY Bridge were predicted. Abundance data for shortnose and Atlantic sturgeon derived from fisheries sampling were combined with data about the spatial extent of pile-driving noise. This approach was used to calculate the number of sturgeon that could...

Computational models based on the finite difference (FD) method can be successfully used to predict underwater pressure waves generated by marine impact pile driving. FD-based models typically discretize the equations of motion for a cylindrical shell to model the vibrations of a submerged pile in the time domain. However, because the dynamics of a...

Shipping traffic is the largest contributor of anthropogenic noise in the ocean. Chronic exposure to shipping noise may be a significant habitat-level stressor to marine fauna. While sound measurements can characterise shipping noise at discrete locations and depths, acoustic models can predict anthropogenic sound levels over large regions of the o...

Most attention about the acoustic effects of marine survey sound sources on marine mammals has focused on airgun arrays, with other common sources receiving less scrutiny. Sound levels above hearing threshold (sensation levels) were modeled for six marine mammal species and seven different survey sources in shallow water. The model indicated that o...

Shipping traffic is the largest contributor of anthropogenic noise in the ocean.Chronic exposure to shipping noise may be a significant habitat-level stressor to marine fauna. Whilesoundmeasurements can characterise shipping noiseat discrete locationsand depths, acoustic models can predict anthropogenic sound levels over large regions of the oceanp...

Marine impact pile driving generates very high underwater sound pressures that can be harmful to aquatic life. Environmental assessments for pile driving projects typically require advance estimates of acoustic impact zones for marine mammals and fish. A computer model has been developed to predict the radiated acoustic field from impact driving of...

In this paper, we compare airgun sound levels measured during an offshore seismic survey to acoustic model predictions. The survey occurred in deep water (>650 m), on and beyond the continental slope in the Canadian Beaufort Sea. The modeling was performed with JASCO Applied Sciences' Marine Operations Noise Model, which uses a parabolic-equation-b...

JASCO Applied Sciences performed acoustic modeling and measurements to calculate marine mammal exclusion zones for Chevron Canada Limited's 2012 Sirluaq 3-D seismic program in the Canadian Beaufort Sea. The Sirluaq survey was located in deep water (>650 m), on and beyond the continental slope, and presented unique challenges from both modeling and...

Including ocean noise in marine spatial planning requires predictions of noise levels on large spatiotemporal scales. Based on a simple sound transmission model and ship track data (Automatic Identification System, AIS), cumulative underwater acoustic energy from shipping was mapped throughout 2008 in the west Canadian Exclusive Economic Zone, show...

The Steller sea lion (Eumetopias jubatus) is a species of conservation concern and is protected from anthropogenic disturbances by federal legislation in Canada and the United States. Although the breeding population has tripled since intensive culling ended ~40 y ago, conservation concerns persist due in part to the species’ vulnerability to anthr...

This article presents a technique for modeling sound propagation from an airgun array, using the parabolic equation (PE) method, that takes into full account the far-field, angle-dependent radiation pattern of the array. This is achieved by generating a PE starting field for the array by summing together shaded, phase-shifted replicas of the PE sel...

A transmission loss experiment was carried out during the winter in south Hecate Strait using a small airgun array source. Airgun pulses were recorded at horizontal receiver ranges between 20 m and 10 km using a bottom-mounted hydrophone recorder. Transmission loss values were computed by subtracting measured source levels from received sound level...

This article presents a technique for modeling sound propagation from an airgun array, using the parabolic equation (PE) method, that takes into full account the far-field, angle-dependent radiation pattern of the array. This is achieved by generating a PE starting field for the array by summing together shaded, phase-shifted replicas of the PE sel...

Sound generated in the ocean by human activities has the potential to be disturbing or harmful to marine fauna. Environmental assessments of offshore industrial activities must often include noiseimpact studies for regulatory approval. Such noiseimpact studies examine the spatial extent of underwater noise using a computermodel to estimate the prop...

An increasing number of Arctic animal populations are listed as threatened. The list includes ungulates, terrestrial carnivores, marine mammals, and birds. Potential threats are habitat degradation and loss, pollution, prey depletion, harvesting pressure (as a result of human population growth), climate change, and noise. Growing exploration and in...

Noise and ground vibration generated by environmental remediation activities were measured in man-made polar bear (Ursus maritimus) dens at Flaxman Island, Alaska in Mar. 2002. The remediation activities involved use of heavy excavation equipment, ground vehicles, and blasting. Comparison of sound levels measured inside and outside the dens permitt...

A technique for modeling sound propagation from an airgun array using the parabolic equation (PE) method is presented that takes into full account the far?field, angle?dependent directionality pattern of the array. This is achieved by generating a PE starting field for the array by summing together shaded, phase?shifted replicas of the PE self?star...

Seismic airguns produce considerable amounts of acoustic energy that have the potential to affect marine life. This study investigated the effects of exposure to an airgun array in the Mackenzie River Delta on the hearing of three fish species: northern pike (Esox lucius), broad whitefish (Coregonus nasus), and lake chub (Couesius plumbeus). Fish w...

Seismic airguns produce considerable amounts of acoustic energy that have the potential to affect marine life. This study investigates the effects of exposure to a 730 in.3 airgun array on hearing of three fish species in the Mackenzie River Delta, the northern pike (Esox lucius), broad whitefish (Coregonus nasus), and lake chub (Couesius plumbeus)...

A recent numerical modeling study has examined the propagation of underwater noise from potential seismic survey activity in Hecate Strait and Queen Charlotte Sound, Canada. Noise level predictions from this study are based on an integrated modeling approach incorporating an airgun array source model, a broadband transmission loss model, and an env...

In July 2004 Fisheries and Oceans Canada supported a study to investigate effects of seismic airgun signals on hearing organs of freshwater fish in the Mackenzie River at Inuvik, NWT Canada. The study required particle velocitymeasurements for correlation with observed biological effects. JASCO Research built a pressure gradient measurement apparat...

Environmental impact assessments for seismic surveys often include estimates of radially propagating sound levels, which are used to determine marine mammal impact zones. Sound levels may be estimated using computer‐based acoustic modelling techniques but these require an accurate description of the survey source signature—arrays of airguns, in par...