The 7m juvenile cetacean was first seen near the dam, which harnesses the tidal power of the Rance estuary to generate electricity, at 10:00 on Thursday morning.
It was seen several times in the area through the course of the day.
Électricité de France, which runs the barrage, immediately turned off its 24 turbines. Some of the power they produce is supplied to Jersey via undersea cables from Normandy.
@SeaShepherdFran avez-vous été informé de la baleine à bosse à l’usine hydro de la rance? https://t.co/LEMLpTuWGK
— ❄️ (@SaS_726) February 10, 2023
WATCH: Video of the whale close to the Rance Barrage.
Today, the barrage’s lock will be open for seven hours – much longer than normal – to hopefully allow the humpback to return to the sea.
The first official sighting of a humpback whale off Jersey was in 2017, when two fishermen spotted one 15 miles west of St. Ouen’s Bay.