Acoustic Effects of Naval Sonar on Bottlenose Dolphins


DISCOVERY Yacht Valkyrie
Catalina Island, California
October 13 - 25, 2023

Research Team

  • Ari Friedlander
  • Brandon Southall
  • Caroline Casey
  • Senele Fregosi
  • John Durban
  • Holly Fearhnbach
  • John Calambokidis

Project Overview

The purpose of this research is to assess the effects, if any, that Navy sonar might have on cetacean populations (specifically bottlenose dolphins) off the coast of Catalina Island in southern California.

Duration of Project

This projects has been ongoing for several years

Expedition Summary

During October 13th - 25th, The International SeaKeepers Society assisted Dr. Ari Friedlaender and the California Ocean Alliance in conducting field research off the coast of southern California. The team, which consisted of biologists, acousticians, and conservationists, worked in collaboration with DISCOVERY Yacht Valkyrie, owned and operated by Tom Petersen. This project seeks to investigate detailed aspects of the movement and acoustic behavior as well as physiological aspects of bottlenose dolphins. Using controlled sound experiments simulating Navy sonar, the team observes and records how these human noises in the dolphins’ environment affect their health and behavior using carefully controlled methods. D/Y Valkyrie was essential on this expedition, serving as the hub of operations for visual surveys, coordinating small boat operations, acting as the launch platform for drone operations, and housing the research team.


This research will hopefully help to inform Naval activities of the impacts of sonar on marine mammals and best practices or guidelines if, when, and how to use sonar in the presence of certain species.


Catalina Island, California