Behavioral response of select reef fish and sea turtles to mid-frequency sonar

Abstract

There is growing concern over the potential effects of high-intensity sonar on wild marine species populations and commercial fisheries. Acoustic telemetry was employed to measure movements of free-ranging reef fish and sea turtles in Port Canaveral, Florida, in response to routine submarine sonar testing. Twenty-five sheepshead (Archosargus probatocephalus), 28 gray snapper (Lutjanus griseus), and 29 green sea turtles (Chelonia mydas) were tagged, with movements monitored for a period of up to four months using an array of passive acoustic receivers. Baseline residency was examined for fish and sea turtles before, during, and after the test event. No mortality of tagged fish or sea turtles was evident from the sonar test event. There was a significant increase in daily residency index for both sheepshead and gray snapper at the testing wharf subsequent to the event. No broad-scale movement from the study site was observed during or immediately after the test. One month after the sonar test, 56% of sheepshead, 71% of gray snappers, and 24% of green sea turtles were still detected on receivers located at the sonar testing wharf.