– We have done an acoustic inventory where we sailed over an area and recorded sounds from the porpoise where it emits clicking sounds when it tries to find food, says Alexandra Colbing, marine environment manager at the Gotland County Administration.
With the help of a hydrophone, they have picked up the clicking sounds to be able to see if the porpoise is in the area or not.
In the clip above, you can hear what humans can do to bring the porpoise back to the Baltic Sea.