Southall Environmental Associates, Inc.


SOCAL-15 continues a multi-year research collaboration called the “SOCAL-BRS” (Southern California Behavioral Response Study). This project is designed to better understand the behavior of numerous 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 mid-frequency active sonar (MFAS) systems 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.

Click here to view the SOCAL-15 Public Summary



Tagged blue whale (Photo: Ari Friedlaender)

Several successful field seasons of SOCAL-BRS have already been completedand over 170 tags have been deployed on individuals of nine different species and 83 complete experimental BRS sequences have been 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). The results of these experiments have been presented in scientific meetings and increasingly in the scientific literature (please see numerous papers available at for more detailed discussion).

SOCAL-15 will use similar configurations, protocols, focal species, equipment, and areas with an increasing reliance on smaller, adaptive vessel configurations. SOCAL-15 will build on earlier integrations of CEE methods with ongoing regular training operations to directly use Navy sonar systems in experimental applications. Whales will opportunistically be tagged around these activities at much greater distances than typically used in simulated sonar exposures. The experimental objective is to match received sound levels with those tested using simulated sonars but in a completely realistic scenario to study the relative effects on behavior of source type, received sound level, and physical range to sound sources.


SOCAL-BRS is a study of basic behavior and responses to controlled sound exposures in a variety of marine mammal species.

Southall Environmental Associates, Inc.

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