Marine mammal observations and mitigation associated with USGS seismic surveys in the southern California Bight in 1999
Quan, J. and J. Calambokidis. 1999. Marine mammal observations and mitigation associated with USGS seismic surveys in the southern California Bight in 1999. Report to U.S. Geological Survey, Menlo Park, CA. Cascadia Research, 218½ W Fourth Ave., Olympia, WA 98501. 16pp
From 6 to 17 June 1999 (4 to 5 June were transit days), the U.S. Geological Survey conducted seismic-reflection surveys in the coastal waters of the Pacific Ocean, between Los Angeles and San Diego, to investigate earthquake hazards. As a part of this project, Cascadia Research was contracted by the USGS to monitor marine mammals from the survey platform and provide mitigation on impacts on marine mammals by requesting shutdown of the sound sources when marine mammals were close to the operations.
This report summarizes the results of a marine mammal mitigation and monitoring program conducted in conjunction with these USGS surveys and adds information to similar work conducted by Cascadia Research in 1998 (Calambokidis et al 1998b). There were several modifications to observations and mitigation operations made for the 1999 survey from that in 1998: 1) Three observers were on board with two on duty during daylight observations, 2) the mitigation safety zone was extended from 200 meters to 250 meters for baleen and sperm whales, and 3) airgun operations during the night time hours were suspended.