Southall Environmental Associates, Inc.


View the SOCAL-11 Final Project Report

SOCAL-11 is second field season of a multi-year effort (2010-2014), more generally referred to as “SOCAL-BRS” (Behavioral Response Study); for more information on our very successful first field season please see SOCAL-10. SOCAL-11 is an interdisciplinary study of basic behavior and responses to controlled sound exposures in a variety of marine mammal species, building on a number of related efforts. The overall objective is to provide a better scientific basis for estimating risk and minimizing effects of active sonar for the U.S. Navy and regulatory agencies. SOCAL-BRS is part of a larger international collaboration to measure the impacts of noise marine mammals using opportunistic and experimental approaches (including controlled exposure experiments, or “CEEs”).

Specific objectives for SOCAL-11 include:

(1) Obtaining baseline behavioral data on a range of marine mammal species.

(2) Conducting CEEs on baleen whales, beaked whales, Risso’s dolphins, sperm whales.

(3) Testing optimal configuration for subsequent studies, which may include realistic/actual military sources.

(4) Obtaining data to support the Navy’s SOCAL range monitoring efforts

A more detailed summary of SOCAL-11 is also available here. This project is very much an interdisciplinary collaboration of biologists, acousticians, engineers, and other scientists from a variety of academic, private, and government research organizations. Brief descriptions of the roles of these organizations in the overall SOCAL BRS effort are given here.

Leg I: July 29 – August 11, 2011
Leg II: September 17 – 30, 2011

SOCAL-11 operational area includes both “inshore” areas along southern California from Morro Bay to San Diego and an offshore area that includes the U.S. Navy’s SCORE range near San Clemente Island. SOCAL-11 sound transmissions will occur more than 1nm from any land mass and 4 more than 3nm from any land mass within the Channel Islands National Marine Sanctuary (CINMS).

Cascadia Research personnel coordinate and conduct small boat operations and visual observations for the SOCAL BRS. Cascadia is responsible for the charter of the larger vessels used and providing the two RHIBs used for tag deployments and focal follows. Cascadia personnel are centrally-involved in planning and data analysis related to the project.

Southall Environmental Associates researchers are responsible for overall coordination and execution of SOCAL BRS. This includes coordinating study design; ensuring compliance with all requisite permits, authorizations, protocols, and reporting; field execution; data management; coordinating data analysis and publication; and leading outreach efforts related to public education and the interpretation of results.

NOAA’s National Marine Fishery Service, Southwest Fishery Science Center is developing methods for real-time detection, localization, identification, and tracking of beaked whales. This development includes hardware (towed linear and tetrahedral arrays) and software (to be included within Pamguard as integrated modules). These methods can be used independently, or in conjunction with other methods, to improve detection and tagging of these species during BRS surveys. SWFSC scientists are also using fisheries acoustic technologies to measure the distribution and density of prey being exploited by foraging mysticete whales involved in behavioral studies.

Woods Hole Oceanographic Institution researchers have developed some of the acoustic and position-orienting sensors used SOCAL-BRS. WHOI scientists are also directly involved in tag deployment and tracking, data analysis, and interpretation of results.

Duke University Marine Laboratory colleagues bring expertise from a wide variety of marine mammal tagging and behavioral ecology studies to the SOCAL BRS effort. Researchers are involved in the design and execution of small boat and tagging operations and are also participating in prey-mapping efforts contributing to studies on mysticete foraging ecology.

Scripps Institution of Oceanography researchers have participated in field research efforts, including the second leg of SOCAL-10 which was conducted aboard the SIO R/V Robert Gordon Sproul. Scripps researchers contribute expertise in acoustic analysis of tag data and from remote deployed sensors such as sonobuoys.

SSC Pacific scientists have developed custom, data logging and geospatial display software called the Whale Identification Logging and Display (WILD) system. WILD integrates different kinds of biological and other information into a common, GIS-based viewing and analytical environment. This system is critical in real-time decision-making for SOCAL BRS research activities as well as for data archive and analysis.

Naval Undersea Warfare Center engineers and acousticians perform a number of key roles in the SOCAL BRS effort related to the measurement, interpretation, and generation of underwater sounds. NUWC personnel use an array of listening devices to characterize the marine environment, including the detection and localization of marine mammals. NUWC staff also test, calibrate, and operate the SOCAL BRS underwater sound source used in controlled exposure experiments.

Applied Physical Sciences engineers designed, constructed, and calibrated the underwater sound source used in the SOCAL BRS.


SOCAL-BRS RESOURCE SPONSORS are the U. S. Navy, Chief of Naval Operations, Environmental Readiness Division (OPNAV N45) and the Office of Naval Research, Marine Mammal Research Program.

SOCAL-BRS FUNDING COORDINATORS are the Naval Postgraduate School, Monterey, CA. NPS acousticians are also contributing to field operations in SOCAL-11.


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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