We are pleased to announce that the following article has just been published. Holt, M.M., Noren, D., and Emmons, C. 2011. The effects of noise levels and call types on the source levels of killer whale calls. Journal of the Acoustical Society of America.130: 3100-3106. The publication is available online at: http://link.aip.org/link/?JAS/130/3100 Abstract: Accurate parameter estimates relevant to the vocal behavior of marine mammals are needed to assess potential effects of anthropogenic sound exposure including how masking noise reduces the active space of sounds used for communication. Information about how these animals modify their vocal behavior in response to noise exposure is also needed for such assessment. Prior studies have reported variations in the source levels of killer whale sounds, and a more recent study reported that killer whales compensate for vessel masking noise by increasing their call amplitude. The objectives of the current study were to investigate the source levels of a variety of call types in southern resident killer whales while also considering background noise level as a likely factor related to call source level variability. The source levels of 763 discrete calls along with corresponding background noise were measured over three summer field seasons in the waters surrounding the San Juan Islands, WA. Both noise level and call type were significant factors on call source levels (1–40 kHz band, range of 135.0–175.7 dB_rms re 1 µPa at 1 m). These factors should be considered in models that predict how anthropogenic masking noise reduces vocal communication space in marine mammals. © 2011 /Acoustical Society of America/ -- __________________________________ Marla M. Holt, Ph.D. Research Wildlife Biologist Marine Mammal Ecology Team NOAA/NMFS Northwest Fisheries Science Center 2725 Montlake Blvd East Seattle, WA 98112 www.nwfsc.noaa.gov/research/divisions/cbd/marine_mammal/marinemammal.cfm