SOCAL-13 continues the multi-year effort (2010-2015) project “SOCAL-BRS” (Southern California Behavioral Response Study). This project is designed to better understand the behavior of a number of protected marine mammal species that inhabit the southern California Bight and provide direct, controlled measurements of their reactions to sound, including military sonar systems. The overall objective is to provide a better scientific basis for estimating risk and minimizing effects of sonar for the U.S. Navy and regulatory agencies. SOCAL-BRS includes collaborations among the National Oceanic and Atmospheric Administration (NOAA), private sector and academic scientists, and U.S. Navy researchers. It is jointly funded by the U. S. Navy Living Marine Resources Program (LMR) and the Office of Naval Research (ONR) and is part of an international collaboration to measure the impacts of noise on marine mammals. Three successful field seasons of SOCAL-BRS have been completed using an adaptive approach that optimizes the probability of good weather and finding and tagging different focal species. Over 120 tags have been deployed on individuals of nine different species and 55 complete experimental BRS sequences conducted on individuals from seven different federally protected marine mammal species (Cuvier’s beaked whale, Baird’s beaked whale, sperm whale, Risso’s dolphin, blue whale, fin whale, and humpback whale).
SOCAL-13 will use similar configurations, protocols, focal species, equipment, and areas, as previous field seasons with a few modifications. These include the testing and deployment of an even lighter sound source and smaller vessel configurations. Additionally, building on the experiences and planning in previous seasons and in coordination with ongoing Navy training operations, SOCAL-13 will for the first time include the use of realistic Navy sonar systems in experimental applications coordinated with already planned and regular training operations. SOCAL-BRS will attempt to tag whales opportunistically around these activities at much greater distances than used in our simulated sonar sound exposures to date. The experimental objective is to match received sound levels with those tested but in a completely realistic scenario. These experiments will mark the first such integration of realistic operations in behavioral response studies for mid-frequency military sonar and they are being closely coordinated and planned with the Navy and regulatory agencies.