construction noise

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Kendall, LS, Širović A, Roth EH.  2013.  Effects of construction noise on the Cook Inlet beluga whale (Delphinapterus leucas) vocal behavior. Canadian Acoustics. 41(3):3-13. Abstract

Cook Inlet beluga whales (Delphinapterus leucas) are listed as endangered under the US Endangered Species Act. Potential threats to this population include anthropogenic noise and coastal zone development. The Port of Anchorage Marine Terminal Redevelopment (MTR) Project, taking place in the Knik Arm of Cook Inlet, Alaska, involves multiple construction activities including dredging, gravel fill and pile driving. The impacts of construction noise on beluga vocalizations were investigated in this study. Passive sonobuoys were deployed in a four mooring array during 20 d in August and September 2009 near the MTR Project. Data were recorded in real-time at a shore-based observation station. No beluga whistles or noisy vocalizations were recorded during this period; however, beluga echolocation clicks were frequently detected. An energy summation method was used to automatically detect echolocation clicks. Times with and without construction noise (i.e., dredging and pile driving) were determined from long-term spectral averages. The detected hourly click rate was higher during times without (429 detected clicks/h) than with (291 detected clicks/h) construction activity; however, the difference was not statistically significant (t (24) = -0.56, P = 0.58). Lower frequency beluga whale vocalizations (e.g., whistles) were potentially masked, there may be have been an overall reduction in beluga vocalizations, or it is possible belugas were avoiding the area during construction activity.