Dear Colleagues, My co-authors and I are pleased to announce that a new publication is now available: Holt, M.M., Ghoul, A., and Reichmuth, C.J. 2012. Temporal summation of airborne tonal signals in a California sea lion (*Zalophus californianus*). *Journal of the Acoustical Society of America *132: 3569-3575. ABSTRACT: The trade-off between sound level and duration on hearing sensitivity (temporal summation) was investigated in a California sea lion ( *Zalophus californianus*) using airborne pure-tone stimuli. Thresholds were behaviorally measured using the method of constant stimuli at 2.5, 5, and 10 kHz for nine signal durations ranging from 25 to 500 ms. In general, thresholds decreased as duration increased up to 300 ms, beyond which thresholds did not significantly improve. When these data were fitted separately to two versions of an exponential model, the estimated time constants (92–167 ms) were generally consistent between the two fits. However, the model with more free parameters generated fits with consistently higher *R*2 values, while avoiding potential arbitrary decisions about which data to include. The time constants derived for the California sea lion were generally consistent with those reported for other mammals, including other pinnipeds. The current study did not show a clear correlation between time constant and test frequency. The results should be considered when conducting audiometric work, assessing communications ranges, and evaluating potential noise impacts of airborne tonal signals on California sea lions. © 2012 *Acoustical Society of America* The full article can be found online at: http://asadl.org/jasa/resource/1/jasman/v132/i5/p3569_s1 -- __________________________________ Marla M. Holt, Ph.D. Research Wildlife Biologist Marine Mammal & Seabird Ecology Team Conservation Biology Division NOAA/NMFS Northwest Fisheries Science Center 2725 Montlake Blvd East Seattle, WA 98112 Phone: 206.860.3261 Fax: 206.860.3475 www.nwfsc.noaa.gov/research/divisions/cbd/marine_mammal/marinemammal.cfm <http://www.nwfsc.noaa.gov/research/divisions/cbd/marine_mammal/marinemammal.cfm>