Temporary Hearing Threshold Shift in California Sea Lions (Zalophus californianus) Due to One-Sixth-Octave Noise Bands Centered at 2 and 4 kHz: Effect of Duty Cycle and Testing the Equal-Energy Hypothesis
Ronald A. Kastelein, Lean Helder-Hoek, Linde N. Defillet, Léonie A. E. Huijser, John M. Terhune, Robin Gransier
Abstract
sponsorship: We thank assistants Suzanne Cornelisse, Femke Kuiphof, and Stacey van der Linden; students Irna Huisjes, Anouk van der Horst, Roos de Lepper, Pepijn Degger, Luna Korsuize, and Eline Theuws; and volunteer Manouk Vermeulen for their help in collecting the data. We thank Arie Smink for the design, construction, and maintenance of the electronic equipment. We thank Bert Meijering (Topsy Baits) for providing space for the SEAMARCO Research Institute. Erwin Jansen (TNO, the Hague, the Netherlands) conducted the acoustic calibration measurements. We also thank Nancy Jennings (Dotmoth.co.uk) and the anonymous reviewers for their valuable constructive comments on this manuscript. Funding for this study was obtained from the U.S. Navy's Living Marine Resources program (Contract No. N-39430-20-C-2215). We thank Mandy Shoemaker and Anu Kumar for their guidance on behalf of the LMR program. The sea lions were made available for the research by Blijdorp Zoo, Rotterdam, the Netherlands. The training and testing of the California sea lions was conducted under authorization of the Netherlands Ministry of Economic Affairs, Department of Nature Management. (U.S. Navy's Living Marine Resources program|N-39430-20-C-2215)