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PubMed | Subacoustech Environmental Ltd, Loughine Ltd and University of Hull
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

To assess and manage the impact of man-made sounds on fish, we need information on how behavior is affected. Here, wild unrestrained pelagic fish schools were observed under quiet conditions using sonar. Fish were exposed to synthetic piling sounds at different levels using custom-built sound projectors, and behavioral changes were examined. In some cases, the depth of schools changed after noise playback; full dispersal of schools was also evident. The methods we developed for examining the behavior of unrestrained fish to sound exposure have proved successful and may allow further testing of the relationship between responsiveness and sound level.

Hawkins A.D.,Loughine Ltd | Pembroke A.E.,Normandeau Associates | Popper A.N.,University of Maryland University College
Reviews in Fish Biology and Fisheries | Year: 2014

The expansion of shipping and aquatic industrial activities in recent years has led to growing concern about the effects of man-made sounds on aquatic life. Sources include (but are not limited to) pleasure boating, fishing, the shipping of goods, offshore exploration for oil and gas, dredging, construction of bridges, harbors, oil and gas platforms, wind farms and other renewable energy devices, and the use of sonar by commercial and military vessels. There are very substantial gaps in our understanding of the effects of these sounds, especially for fishes and invertebrates. Currently, it is almost impossible to come to clear conclusions on the nature and levels of man-made sound that have potential to cause effects upon these animals. In order to develop a better understanding of effects of man-made sound, this paper identifies the most critical information needs and data gaps on the effects of various sounds on fishes, fisheries, and invertebrates resulting from the use of sound-generating devices. It highlights the major issues and discusses the information currently available on each of the information needs and data gaps. The paper then identifies the critical questions concerning the effects of man-made sounds on aquatic life for which answers are not readily available and articulates the types of information needed to fulfill each of these drivers for information—the key information gaps. Finally, a list of priorities for research and development is presented. © 2014, Springer International Publishing Switzerland.

PubMed | University of Maryland University College, Loughine Ltd, CSA Ocean science Inc., Smith-Root, Inc. and 3 more.
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

Pallid sturgeon and paddlefish were placed at different distances from a seismic air gun array to determine the potential effects on mortality and nonauditory body tissues from the sound from a single shot. Fish were held 7 days postexposure and then necropsied. No fish died immediately after sound exposure or over the postexposure period. Statistical analysis of injuries showed no differences between the experimental and control animals in either type or severity of injuries. There was also no difference in injuries between fish exposed closest to the source compared with those exposed furthest from the source.

PubMed | Georgia Institute of Technology, University of Maryland University College, Loughine Ltd and National Oceanic and Atmospheric Administration
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

Researchers often perform hearing studies on fish in small tanks. The acoustic field in such a tank is considerably different from the acoustic field that occurs in the animals natural environment. The significance of these differences is magnified by the nature of the fishs auditory system where either acoustic pressure (a scalar), acoustic particle velocity (a vector), or both may serve as the stimulus. It is essential for the underwater acoustician to understand the acoustics of small tanks to be able to carry out valid auditory research in the laboratory and to properly compare and interpret the results of others.

PubMed | National Oceanic and Atmospheric Administration, University of Washington, University of Maryland University College and Loughine Ltd
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

Auditory evoked potentials (AEPs) have become popular for estimating hearing thresholds and audiograms. What is the utility of these measurements? How do AEP audiograms compare with behavioral audiograms? In general, AEP measurements for fishes and marine mammals often underestimate behavioral thresholds, but comparisons are especially complicated when the AEP and behavioral measures are obtained under different acoustic conditions. There is no single representative relationship between AEP and behavioral audiograms and these audiograms should not be considered equivalent. We suggest that the most valuable comparisons are those made by the same researcher using similar acoustic conditions for both measurements.

PubMed | Loughine Ltd., Georgia Institute of Technology, University of Maryland University College and National Oceanic and Atmospheric Administration
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

In this paper, we discuss the issues encountered when trying to perform hearing experiments in water-filled tanks that are several meters in lateral extent, typically large in terms of the size of the animals under study but not necessarily so with respect to the wavelengths of interest. This paper presents measurements of pressure and particle motion fields in these large tanks. The observed characteristics and complexities are discussed in reference to their potential impact on the planning and interpretation of hearing experiments.

PubMed | Loughine Ltd. and University of Maryland University College
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

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.

PubMed | University of Washington, Loughine Ltd, Smith-Root, Inc., ProBioSound LLC and 3 more.
Type: Journal Article | Journal: PloS one | Year: 2016

This study examined the effects of exposure to a single acoustic pulse from a seismic airgun array on caged endangered pallid sturgeon (Scaphirhynchus albus) and on paddlefish (Polyodon spathula) in Lake Sakakawea (North Dakota, USA). The experiment was designed to detect the onset of physiological responses including minor to mortal injuries. Experimental fish were held in cages as close as 1 to 3 m from the guns where peak negative sound pressure levels (Peak- SPL) reached 231 dB re 1 Pa (205 dB re 1 Pa2s sound exposure level [SEL]). Additional cages were placed at greater distances in an attempt to develop a dose-response relationship. Treatment and control fish were then monitored for seven days, euthanized, and necropsied to determine injuries. Necropsy results indicated that the probability of delayed mortality associated with pulse pressure following the seven day monitoring period was the same for exposed and control fish of both species. Exposure to a single pulse from a small air gun array (10,160 cm3) was not lethal for pallid sturgeon and paddlefish. However, the risks from exposure to multiple sounds and to sound exposure levels that exceed those reported here remain to be examined.

Krysl P.,University of California at San Diego | Hawkins A.D.,Loughine Ltd | Schilt C.,Bigleaf Science Services | Cranford T.W.,Quantitative Morphology Consulting Inc.
PLoS ONE | Year: 2012

Fish can sense a wide variety of sounds by means of the otolith organs of the inner ear. Among the incompletely understood components of this process are the patterns of movement of the otoliths vis-à-vis fish head or whole-body movement. How complex are the motions? How does the otolith organ respond to sounds from different directions and frequencies? In the present work we examine the responses of a dense rigid scatterer (representing the otolith) suspended in an acoustic fluid to low-frequency planar progressive acoustic waves. A simple mechanical model, which predicts both translational and angular oscillation, is formulated. The responses of simple shapes (sphere and hemisphere) are analyzed with an acoustic finite element model. The hemispherical scatterer is found to oscillate both in the direction of the propagation of the progressive waves and also in the plane of the wavefront as a result of angular motion. The models predict that this characteristic will be shared by other irregularly-shaped scatterers, including fish otoliths, which could provide the fish hearing mechanisms with an additional component of oscillation and therefore one more source of acoustical cues. © 2012 Krysl et al.

McWilliam J.N.,Northumbria University | Hawkins A.D.,Loughine Ltd
Journal of Experimental Marine Biology and Ecology | Year: 2013

Sound travels well through water and is capable of conveying information to any listener on both the presence of particular organisms and the quality of the environment. Many marine organisms use sounds to navigate, forage and communicate, while different marine habitats often have their own acoustical characteristics. However, there are still large gaps in our knowledge of marine soundscapes, particularly in regard to their spatial patterns. The goal of this research was to investigate passive acoustic monitoring as an ecological survey technique. The specific objectives were to compare soundscapes between and within benthic habitats and to evaluate the influence of different environmental factors. Acoustic recordings were made in Lough Hyne, Ireland during May 2012, following a nested design in three benthic habitats; Mud, Gravel and Cliff. Three patches of each habitat were selected using hydro-acoustic and underwater video surveys and within each patch five different sites were monitored (n. = 45). A nested analysis of variance (ANOVA) showed that acoustic profiles differed significantly within but not between habitats, although unique acoustic signatures existed over different spatial ranges, illustrating a degree of stability at local patch level. A distinct peak (2-4. kHz) in acoustic complexity was observed in all habitat patches but one, and was caused by the presence of transient broadband pulses or snaps. These snaps were attributed to the presence of snapping shrimp (family Alpheidae), found at a particular location within the lough. Other distinctive sounds of suspected biological origin were identified in particular habitat patches (Cliff and Gravel) and suggested the presence of habitat related biophonies. Soundscape signatures of different patches were strongly correlated with proximity to the source of the high-energy snaps, indicating that location was more important than habitat in determining soundscape characteristics. Other environmental factors such as bottom type and depth were less important. It is evident that acoustical sources of high energy and broadband properties have pervasive effects over considerable distances (up to 1. km). The acoustic characteristics of a habitat patch were greatly influenced by extraneous sounds, in this case from a biological source. The high acoustic connectedness of marine habitats underlines the need for evaluating the impact of anthropogenic activities, particularly for ecosystems with unique biophonies in need of protection. There is potential for developing passive acoustic monitoring as a principal method for surveying marine habitats and observing local processes at different spatial and temporal scales. © 2013 Elsevier B.V.

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