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This project developed acoustical systems for monitoring of wildlife sounds over large areas where access is limited. These systems were tested at Fort Hood, Texas, where Golden-cheeked Warblers and Black-capped Vireos are managed intensively. A balloon system was designed to carry digital audio recorders across inaccessible areas. Horn-loaded microphones were developed to provide lightweight acoustical sensors that were highly sensitive to bird songs and deemphasized low-frequency noise from military training activity. The balloon control system included GPS track logging, altitude control, and bidirectional wireless communications., The original document contains color images. SERDP(Strategic Environmental Research and Development Program), SERDP Collection.

El primer objetivo del trabajo tiene como fin describir el patrón de presencia estacional del rorcual común en las diferentes áreas de estudio a lo largo de la región occidental del mar Mediterráneo. La determinación de los meses de mayor y menor presencia de las ballenas en cada área de estudio permite contrastar si existe un patrón de presencia estacional en la región occidental del mar Mediterráneo. El segundo objetivo del trabajo tiene como fin confirmar y describir la presencia de un patrón migratorio estacional en la población del rorcual común en el Mediterráneo occidental. La comparación de los diferentes patrones de presencia estacional a lo largo de la región Mediterránea de la Península Ibérica permite contrastar si la población de rorcual común del mar Mediterráneo se desplaza hacia el norte en primavera y hacia el sur en otoño o si por el contrario no presenta un patrón migratorio estacional definido.

The project goals are to map the low-frequency (<1000 Hz) ocean noise budget throughout the Stellwagen Bank National Marine Sanctuary (SBNMS) ecosystem, identify and quantify the contributing sources of anthropogenic sounds within that ecosystem, and determine whether or not such noises have the potential to impact endangered marine mammals and fishes that use the Sanctuary. This project represents a high-level, integrative 'bench mark' study aimed at characterizing the marine acoustic environment and the health of an urbanized, productive ecosystem, SBNMS. The primary products will be a suite of tools designed to be transferable to other ecological regions and an extensive database specific to the project. These will include both mechanisms for data collection and analysis as well as a conceptual framework for integrating and interpret the scientific results.

Integrated field research was conducted on the potential impact of man-made underwater sound on marine mammals and the functions of the low-frequency sounds of whales. This was accomplished using passive acoustics, active acoustics, tagging, vessel survey, biopsy sampling, and photo-ID. Relationships were determined between low-frequency vocal rates of individual fin (Balaenoptera physalus) whales; the identity and sex of singers; and the presence, number and distribution of animals. All singers (n = 9) were males. There were correlations between number of whales seen, level of vocal activity and number of singers. There were associations between where and when males sang, food distribution and feeding activity. Contrary to previous assumptions singers concentrated near high densities of food and sang more during periods of high feeding activity. Resultant data are important for estimating relative abundance based on passive acoustic monitoring systems and for models (e.g., AIM) used to predict acoustic impact for mitigation purposes. By placing the biologically important behavior of acoustic communication within the appropriate ecological context, hypotheses on communication functions (e.g., whale sounds are detected throughout the oceans on (USS) can be tested. This should result in a more rigorous understanding on the potential impact of human-produced LFS on large whales., Prepared in cooperation with Institute of Marine Sciences, University of California, Santa Cruz.

This was part of the first major project addressing the potential impact of an operational DoD LFS source on free-ranging marine mammals. Based on available prior research, the expectation was that we would detect obvious and statistically significant responses at received levels of around 120dB re 1 micronPa, and that such changes would be manifested across multiple measures. This was not entirely the case. Although our measures were sensitive enough to detect subtle changes indicating that animals detected the sound, animals were tolerant of received levels between 120-130dB. Most tests for statistical significance were negative. The few statistically significant behavioral responses were subtle, short-term and small-scale. All responses were small relative to natural variation, leading to the interpretation that ATOC LFS has a negligible impact on marine mammals., Prepared in cooperation with Cornell Univ., Lab. of Ornithology, Ithaca. NY.

Acoustic data from a horizontal line array deployed from the R/V Cory Chouest were analyzed for marine mammal sounds in order to assess the accuracy of Navy personnel in detecting and identifying whale vocalizations, and to determine whether there was any evidence of potential impact on whales from SURTASS LFA transmissions. Results were based on an analysis of 386 hours from the LFA-15 exercise, February and March 1996. Detection and identification of blue whale signals was poor in both months, while good for fin whales. Errors had little or no impact on compliance because most of the whale calls that were missed were probably from distant animals. Whale acoustic detections were converted into probability of detection statistics with appropriate confidence intervals, and detection probabilities were compared between the LFA-on and LFA-off conditions. The data provide some evidence that whales are less likely to call when the SURTASS-LFA is transmitting. However, the data for this set of circumstances are too sparse to make an accurate assessment of impact. In order to accurately assess the effects of SURTASS-LFA transmissions on whale call probability, transmissions need to be turned off on a more regular basis for periods of 1 hour or longer.

A three-phased research program was completed to study the effects of SURTASS-LFA sounds on three different species of mysticetes under three different biologically critical contexts. A suite of data collection protocols and techniques were combined to document evidence of response from whales over time scales from a few minutes up to one month, and over distances of approximately 1 to tens of kilometers. Playback experiments were designed to expose whales to received levels of < 155 dB re 1 micro-Pa, but it proved difficult to expose animals to levels > 150 dB, and few were exposed to levels > 140 dB. A whale's reactions to the LFA sound varied depending on RL, social context and proximity to the coast. Some whales did respond at levels between 110-150 dB range, but all of the observed responses lasted less than an hour and occurred over ranges of less than several kilometers. None of the observed reactions were considered biologically significant even for received levels as high as 150 dB. These results are surprising. They require critical rethinking of existing assumptions about sound exposure impacts on individuals and populations, and a re-evaluation of existing regulations regarding permissible levels of underwater sound exposure.