Deploying a hydrophone takes preparation and precision in the deep ocean. The instruments need to be designed for the specific conditions they will endure and the length of time they will be deployed. They also need to be set up for the particular types of data they’re intended to record.
The arctic ocean is very cold, subject to storms and ice that limit the season and time when a hydrophone position can be accessed.
Ice bergs leave deep gouges in the ocean floor. This is called “scouring” and is one of the many hazards that make deployment and retrieval of Arctic hydrophones expensive and challenging. In the hostile Arctic environment the chances of hydrophones and other equipment being destroyed or lost are high.