Research in Ocean Acoustics

Marine Animal Communication Systems
"Blue whale vocalizations in the Gulf of Alaska"
Kate Stafford - NOAA
Acoustic data from an autonomous moored array have been analysed for the seasonal and geographic occurrence of large whales in the Gulf of Alaska. Recordings sampled continuously at 1000 Hz (0-470 Hz working range) from October 1999 - June 2001. Species recorded in the Gulf of Alaska included: eastern and western blue, fin, humpback, sperm and right whales. All baleen whale species showed seasonal and geographic variation in call reception. Work is underway to model detection distances for each of these species.

Monitoring Ambient Noise
"Recovery of LRAPP Acoustic Data"
Dr. Roy Gaul - Applied Research Laboratory, University of Texas (ARL:UT) and Blue Sea Corp.
This project was initiated to recover and digitize data acquired in the 1970s under the Long Range Acoustic Propagation Project (LRAPP) of the Office of Naval Research (ONR). Discussions between NMFS and Navy during the past year have led to mutual interest in recovering previously classified ocean acoustic data acquired by the Navy. These data are particularly useful for assessment of long-term trends of ambient noise that may be pertinent to marine mammals. The LRAPP data were recorded in analog format on magnetic tape and retained at ARL:UT. A recent pilot project (funded by ONR) demonstrated that the data can be recovered and digitized without loss of accuracy. Routine data recovery from multiple locations requires special equipment and customized procedures. The central objective of the ongoing effort is acquisition and set-up of the most critical long-lead equipment item needed to prepare archival magnetic tape for processing.

"GNOMES - Gulf of Mexico Noise Monitoring System"
Doug Nowacek - Department of Oceanography, Florida State University
David Mann - College of Marine Science, University of S. Florida
The Gulf of Mexico Noise Monitoring System (GNOMES) has initially focused on three distinct, primarily estuarine, areas in the eastern Gulf that have varying amounts of human activity, listed from most to least developed: Tampa Bay, Charlotte Harbor, and the Steinhatchee River area. By sampling these different environments we are documenting not only the baseline noise levels in the areas, but also to compare the anthropogenic influence on developed vs. relatively pristine areas of coastline. Our focus is to document anthropogenic noise, but we will also record natural sounds produced by animals in the area, primarily fish and marine mammals. We are currently analyzing recordings made by our small, self-contained recording devices. In general, day time records contain boats and dolphins, while evening and night time recordings are dominated by fish choruses.

Effects of Sound on Hearing and Behavior
"Development of Rapid Behavioral Psychoacoustic Techniques in Marine Mammals"
David Kastak - UC Santa Cruz
Experiments designed to study the effects of anthropogenic noise on hearing in marine mammals typically involve behavioral psychophysical tasks. Such tasks require voluntary participation by captive subjects, are time-consuming, and subjects' physiological and behavioral states often interfere with data collection and interpretation. We are using a psychophysical technique, the method of adjustment (MOA), using two species of pinniped and one species of odontocete, which will considerably shorten the time required to obtain behavioral audiometric data. Data obtained in this way will considerably enhance our knowledge of basic and applied aspects of hearing in marine mammals

"Evoked Potential Hearing Measurements with Cetaceans"
David Mann - USF

"Standardization of Electrophysiological Measures of Hearing in Marine Mammals"
Colleen Kastak - UC Santa Cruz
The primary purpose of this project is to identify the conditions under which electrophysiological methods can be used to investigate auditory sensitivity and function in pinnipeds, and to establish the relationship between such neurological measurements and those obtained using standard behavioral techniques. We first developed two independent systems for the collection and analysis of pinniped evoked potentials produced by exposure to brief airborne sounds. We then used monopolar recording techniques to determine the electrode positions that yielded the optimal evoked response amplitude for each species. The results of these studies provide a general understanding of species-typical auditory evoked responses and advance the long-term goal of using minimally invasive evoked potential techniques to make rapid, quantitative, repeatable, and interpretable measurements of pinniped auditory function.

"TTS Measurements in Odontocete Cetaceans from Multiple Exposures"
James Finneran - SPAWAR Systems Center

Non-Auditory Effects of Sound and/or Explosions
"Blood Nitrogen Uptake and Distribution During Diving in Bottlenose Dolphins"
Dr. Paul Ponganis - Scripps Institution of Oceanography, University of California, San Diego
The goal of this project is to examine blood nitrogen uptake and distribution during diving in a trained bottlenose dolphin. This is relevant to the issue of nitrogen supersaturation in cetaceans, and to the etiology of the mass strandings of beaked whales associated with the use of naval sonar. The project investigates physiological responses during diving including heart rate (a backpack digital ECG recorder), thoracic impedance as a measure of lung collapse (backpack chest impedance recorder), and blood sampling (a backpack blood sampler). The project is conducted in association with the Navy Marine Mammal Facility at Pt. Loma, and in collaboration with another project headed by Dr. Dorian Houser.

"Effects of blast trauma on sea turtle cadavers"
Dr. Darlene Ketten - WHOI

Developing Acoustic Technologies
"Development of acoustic propagation visualization software"
Dr. Adam Frankel - Marine Acoustics, Inc.

Sponsored Professional Meetings/Reports
2006 (planned) - International Symposium following on 2004 meeting "Technological and Economic Considerations of Applying Quieting Technology to Large Commercial Vessels" (sponsor). Details and co-sponsors to be determined.

2005 - "Marine Mammal Populations and Ocean Noise: Determining When Noise Causes Biologically Significant Effects" - National Research Council of the National Academies publication (co-sponsor with Office of Naval Research, National Science Foundation, and Minerals Management Service).

2004 to 2005 - Partial support of Scientific Panel developing Noise Exposure Criteria for Fish and Sea Turtles

2004 - International Symposium "Shipping Noise and Marine Mammals: A Forum for Science, Management, and Technology" (sponsor).

2003 - "Ocean Noise and Marine Mammals" - National Research Council of the National Academies publication (co-sponsor with Office of Naval Research, National Science Foundation, and U. S. Geological Survey)

2003 - Workshop on Temporary Threshold Shift in Marine Mammals at the University of Hawai'i (meeting co-sponsor with Office of Naval Research Marine Mammal Program)

2002 - Workshop on Acoustic Resonance as a Source of Tissue Trauma in Cetaceans [pdf] (meeting sponsor)