Effects Of Anthropogenic Sounds Research Articles

Influence of ocean dynamics on Cuvier’s beaked whale (Ziphius cavirostris): Presence and their prey

Cuvier’s beaked whales (Ziphius cavirostris; Zc) dive below 1000 m to forage predominantly on deep-sea squids. The impact of oceanographic conditions on Zc prey and the effects of anthropogenic sounds on Zc foraging remain unclear. Zc prey distribution is patchy and potentially influenced by mesoscale oceanographic features interacting with local bathymetry. Favorable environmental conditions lead to aggregations of lower trophic level species that attract squid, and potentially increase Zc presence. We collected simultaneous active and passive acoustic data in Tanner Basin, a southern California submarine canyon, intermittently between 2017 and 2022. Passive acoustic data revealed Zc were present throughout all years, with lower presence during late summer and fall. Subsurface Zc 3D track reconstructions indicated a preference for one side of the canyon, where Zc foraged within a layer of potential prey, detected from active acoustic data. Prey concentrations, quantified as volume backscatter strength below ∼1150 m depth, exhibited an increase following the passage of mesoscale features, which were measured using Finite-size Lyapunov Exponents (FSLE). These prey increases drove immediate increases in Zc presence. Understanding potential physical drivers of Zc predator-prey dynamics is a critical first step for assessing natural variability and potential impacts of sonar use on Zc foraging behavior.

Evaluation of Three Sensor Types for Particle Motion Measurement.

All fish sense acoustic particle motion; some species also sense pressure. Concern over the effects of anthropogenic sounds is increasing the need to monitor acoustic particle motion. Particle motion can be measured directly using vector sensors or calculated from pressure gradients. This article compares three devices that measure particle motion: a three-axis accelerometer, a three-axis velocity sensor, and two 4-element hydrophone arrays. A series of sounds (constant-wave tones, white noise, and Ricker wavelets) were played from a fixed-position projector. The particle motion of sounds from imploding light bulbs was also measured.

Challenges in the quantitative assessment of anthropogenic sound in marine environments.

Concerns about the effects of anthropogenic sounds in aquatic environments have increased over the past 2 decades. There is particular concern with the impact to species that are endangered or those that rely on sound for foraging, navigating, and to detect prey and predators. One of the challenges to quantitative assessment is simply characterizing all environments with potentially harmful sound sources and identifying the impacted species (type and population density). In addition, there are challenges to setting the criteria for physiological and nonphysiological (i.e., behavioral) impacts. Environments vary widely from the deep ocean where navy and commercial sonar systems mostly operate to shallow water (including rivers) where construction sites are often located and activities such as pile driving occur. There are challenges related to both the measurement and the prediction of impact in these environments. Measurements are needed to determine if sound levels and species type and density are as expected. Prediction is required to extrapolate beyond the direct measurements and to define a zone‐of‐influence to determine the overall impact. Acoustic analysis includes accurately describing the sound mechanisms and the sound propagation within the zone‐of‐influence. The focus of this presentation will be on the acoustic challenges related to quantitative assessment.

Anthropogenic sound—Introduction and overview of the ambient and anthropogenic environment

Interest in anthropogenic sound in the marine environment has been directed at concerns about the effects of sound on marine mammals. However, fish make up a far larger and more diverse portion of the oceans than do marine mammals, and they hold considerable economic importance internationally. This has led to a growing interest in the effect of anthropogenic sounds on fish in environments ranging from shallow waters near in-shore shipping lanes to the deep sea. Concerns for effects on fish are parallel to those for marine mammals, and include issues ranging from the death of individual animals to the potential for behavioral changes that could lead to impacts on the survival of populations or species. While the body of data on the effects of anthropogenic sounds on fish is still small, and much of the work is not in the peer-reviewed literature, the number of peer-reviewed studies is growing. The purpose of this special session is to provide an overview of what we currently know about the effects of anthropogenic sound on fish, help define the major outstanding questions on these effects, and to provide the basis for discussion of current and future research in order to help resolve these questions.

Effects of Anthropogenic Sounds on Fishes

There is increasing concern regarding the effect of human-generated (anthropogenic) sounds on marine organisms. While most concern is focused on marine mammals, many of the lower frequency (under 1,000 Hz) sounds are also likely to affect fish. Anthropogenic sounds can range from very intense signals such as noise generated by ships and their sonars to far less intense signals such as background sounds in hatcheries and oceanariums. The sounds may affect behavior and/or physiology, although very little is specifically known about how sounds affect fish. Limited data suggest that short- or long-term exposure to loud sounds may alter behavior, and also result in temporary or permanent loss of hearing. In order to better understand this issue, a series of studies are needed that systematically explore both behavioral and physiological effects of different types of sounds on a select group of species at different stages of their development.