Porpoises frolicking on the sea’s surface is a comforting sight, and a signal to the observer that what he/she is seeing is a unique aspect of nature that must be protected.

The area around Horns Rev is popular with porpoises. In fact, at Slugen, which is closer to the coast, and along the western portion of the reef, significant concentrations of porpoises have been noted.

It is very difficult to measure porpoise populations using today’s technology, so Elsam/Eltra are participating in pilot studies in which so-called PODS, which register the porpoise’s "click"-sounds, are placed in the area so that experts can evaluate how important it is for the animal. When the wind farm has been erected, these PODS will help experts measure whether or not the porpoises will abandon the area for good.