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COMPTUEX/JTFEX EA/OEA Final Chapter 4Schlundt et al. (2000) and Finneran and Schlundt (2004). These data are considered the most applicableto mid-frequency sonar because they are based on controlled, tonal sound exposures within the tacticalsonar frequency range.These behavioral response data are an important foundation for the scientific basis of the Navy’spreferred onset behavioral effects at 190 dB re 1 μPa 2 because of the (1) finer control over acousticconditions; (2) greater quality and confidence in recorded sound exposures; and (3) the exposure stimuliclosely match those of interest for COMPTUEX/JTFEX. Since no comparable data exist, or are likely tobe obtained in the near-term, the relationship between the behavioral results reported by Finneran andSchlundt (2004) and wild animals is not known. Although experienced, trained subjects may toleratehigher sound levels than inexperienced animals; it is also possible that prior experiences and resultantexpectations may have made some trained subjects less tolerant of sound exposures. Potential differencesbetween trained subjects and wild animals are accounted for by deriving a conservative proposedthreshold for effect compared to the regulatory definition of harassment (see Section 6.2.2.2).Behavioral Effects to Cetaceans Exposed to Sonar-Like SoundsResearchers conducting TTS experiments with marine mammals have noted certain “behavioralalterations,” or changes from the subjects’ trained behaviors, that tended to occur as the subjects wereexposed to sounds of increasing intensity. Behavioral alterations were generally attempts by the subjectsto avoid the site of previous noise exposures (Schlundt et al., 2000), or attempts to avoid an exposure inprogress (Kastak et al., 1999). On some occasions, subjects became aggressive or refused to furtherparticipate in the test (Schlundt et al., 2000).Schlundt et al. (2000) and Finneran et al. (2001) reported behavioral alterations, defined as deviationsfrom subjects’ normal trained behaviors, and the exposure levels above which they were observed duringcetacean TTS experiments using 1-second tones. Finneran and Schlundt (2004) analyzed the behavioraldata and provided a statistical summary relating altered behaviors to exposure levels. A summary of the3-, 10-, and 20-kHz results from Finneran and Schlundt (2004) – the frequencies most directly relevant toCOMPTUEX/JTFEX – is provided below.A probit analysis technique (Finney, 1971) was used to fit a smooth dose-response curve to the percentaltered behavior versus exposure level data for the pooled dolphin/white whale data set (upper panel).The exposure levels corresponding to specific percentages of sessions with altered behavior were foundby interpolating within the dose-response curve. Exposure levels corresponding to sessions with 25, 50,and 75% altered behavior were 180, 190, and 199 dB re 1 μPa SPL (or 180, 190, and 199 dB re 1 μPa 2 -sEL), respectively. More detailed statistical results are provided in Finneran and Schlundt (2004).To summarize:Behaviors of subjects during intense sound exposures were compared to subjects’ normalbehaviors without intense sound exposures.Each test session was subjectively classified as “normal” or “altered” behavior.The percentage of sessions with altered behavior was calculated as a function of exposure level.The percentage of sessions with altered behavior generally increased with increasing exposurelevel.A smooth dose-response curve was fit to the resulting data.The exposure levels required to produce 25, 50, and 75% behavioral alteration were determinedby interpolating within the dosage-response curve.4-33 February 2007