Acoustic Monitoring
Marine Mammals and Noise
GMI’s professional acoustics team has extensive hands-on experience conducting passive acoustics surveys. When it comes to sound, we have experience and capability working with state-of-the-industry technology and software. Through small- and large-scale surveys, noise monitoring, and impact assessment, GMI can assist clients with acoustics needs.
Our strengths include:
Passive Acoustic Monitoring (PAM)
Passive acoustic monitoring offers the opportunity to document acoustic activity – from both biologic and anthropogenic, or human-made, sources – in an identified study area with the least amount of direct labor and greatest degree of safety to human observers. Passive acoustic gear can be deployed for several days to several months with minimum human intervention, except when data are ready to be retrieved and analyzed. PAM is a technique that has the potential of satisfying a diverse number of objectives.
Purposes of PAM usage in marine mammal studies include:
- Detection of marine mammal calls
- Abundance and density determination
- Tracking movement
- Triangulating location
- Habitat use (diurnal or seasonal, annual activity)
- Effects of noise on animal communication
- Mitigation tool (especially in seismic surveys and anthropogenic noise assessment)
Sound Pressure Level (SPL) Monitoring
SPL monitoring is a technique used to specifically monitor noise levels, which are generally associated with activities that increase sound levels in water, such as construction, and seismic surveys.
GMI has experience using state-of-the-industry technology for monitoring noise levels associated with construction. Using a SPL meter, one can monitor the source level of a given activity, with knowledge of sound propagation in water, calculate the distance this elevated level will travel. From this information, effects on local species can be predicted. SPL monitoring can insure that federal regulations, such as the Marine Mammal Protection Act are upheld.
Related Projects
New Jersey Department of Environmental Protection (NJDEP) Ecological Baseline Study
GMI was contracted by the New Jersey Department of Environmental Protection to perform an ecological baseline study of the marine and avian resources that use state offshore waters (0-20 NM). GMI is responsible for the design and implementation of all survey protocols, oversight of field data collection on the abundance and distribution of marine mammals, sea turtles, birds; real-time oceanographic data; and the management, interpretation, validation, and analysis of all data. The project includes a literature review related to all marine resources, birds, oceanography, fishes, fisheries, and habitat found within the Study Area and vicinity.
Marine Mammal and Acoustic Monitoring, failing pier, Santa Rosa Island, Channel Islands National Park
GMI was contracted by the National Park Service to perform acoustic and marine mammal monitoring in Bechers Bay during the demolition and reconstruction of the pier structure. Coordinating with National Marine Fisheries Service and National Oceanic and Atmospheric Administration, GMI is responsible for the design and implementation of all monitoring protocols, and the management, interpretation, validation, and analysis of all data. GMI acoustics monitor collected data for an ambient noise map of the immediate area surrounding the pier. This was done to allow for comparison to be drawn during the reconstruction phase of the project, when the acoustics monitor conducted real-time noise level monitoring of construction activities. During construction activities, an acoustic safety zone was calculated from sound pressure level (SPL) readings measured in recordings and real-time acoustic monitoring data collected at a measured distance from the sound source.
NOAA Acoustic Analysis: Dolphins in the Shewsbury and Navesink Rivers, NJ
GMI was hired by the National Oceanic and Atmospheric Administration (NOAA) to provide oversight and scientific expertise in the study and evaluation of a perceived marine natural resource threat in northern New Jersey waters. The findings and analysis were compiled by GMI, in collaboration with scientists at a local university. The final report provided NOAA with sufficient evidence to mitigate the controversy stemming from an outpouring of public concern over the well-being of a group of local dolphins, by demonstrating that the species had not been at risk.