Acoustic ‘listening’ devices placed in the sea to measure seismic ‘noise’ activity over a 10 year period have revealed some astounding and very worrying results.
The devices were placed in an area at the bottom of the Atlantic Ocean called the Mid-Atlantic Ridge, and recorded the airgun sounds produced from vessels looking for oil and gas deposits below the seabed. Surprisingly, airgun sounds were recorded almost 4000 km from the survey vessel in areas that are likely occupied by fin whales, and at some locations airgun sounds were recorded almost every day for more than 12 consecutive months. Both airgun and fin whale sounds were also recorded at all sites.
Understanding the true impact of this noise on fin whale communication and on individuals or populations is difficult but, given the distance over which airgun sounds travel, this is very worrying indeed. Fin whale populations are still reduced from whaling activities, and their communication under the water is likely to play and important role in successful future breeding.