Key points
- Hydrophone monitoring found noise above 120 decibels, the U.S. National Marine Fishery Service threshold for a cetacean behavioral response, extends about 3.6 km around the production vessel.
- The main noise source is the vessel’s dynamic positioning thrusters, not seismic equipment; whales or dolphins would have to pass directly underneath the vessel to be physically affected, and onboard monitors will watch for that.
- The collector vehicle, operating at 4,000 meters with no natural light, uses two spotlights that illuminate a pool of seabed roughly 20 to 30 meters around it.
- Surface vessel deck lighting during 24-hour operations may attract ocean-going birds, a risk the video says is common to other high-seas night operations.
