Acoustic Recording Packages (ARPs) are a continuous year-round survey tool for marine mammal presence. They were developed by our lab and they are used in SCORE, SOGLOBEC, as well as the Bering Sea research projects. ARPs are bottom mounted and provide continuous recording at 500 or 1000 samples per second for months. The main components consist of a hydrophone, which is suspended 10 m above the mooring, batteries, ballast weights and a series of electronics handling acoustic release and datalogging.