The Rockhopper: a compact and extensible marine autonomous passive acoustic recording system

This paper describes a compact and extensible marine autonomous passive acoustics recording system, called ROCKHOPPER. The low-noise recorder features a depth rating of 3,500 m and is capable of continuously collecting high-frequency (197 kHz, 24 bits) acoustic data for up to seven months. Because of its small form factor, the ROCKHOPPER can be deployed and recovered by a single person from small vessels, including rigid-hulled inflatable boats (RHIBs). The performance of the instrument was comprehensively evaluated during an offshore deployment in U.S. waters of the northern Gulf of Mexico. Specifically, the analysis encompassed acoustic data collected with five ROCKHOPPER units between May and November 2019. During this period, tropical storm Barry moved through the deployment area, which provided a unique opportunity to study the impacts of a tropical cyclone on the underwater soundscape.