The largest group of dolphins ever seen by the Bottlenose Dolphin Research Institute crossed the Rias Baixas, near Vigo, Galicia, on July 5th.
The pod of over three thousand dolphins were sighted about 40 kilometres from Portuguese territory.
The images captured by the researchers were shared on Facebook and already have tens of thousands of viewings.
The marine biologists say that large groups usually are only spotted off California and South Africa.
The dolphins usually only group together in such large numbers when they come across an abundance of food.
The institute that sighted and recorded the group is a centre for the investigation and study of the behavior of dolphins and whales, operating from a research facility in Galicia, Spain although based in Sardinia.
Click HERE to see the recording
