Urrga is the name given to turbulence on the surface of the water that is observed by hunters looking for dugong and turtle.
A dugong causes a single Urrga with its tail as it propels itself through the sea while it is swimming close to the surface of the water.
The presence of a turtle is also indicated by an Urrga. However, as they are caused by the animal’s flippers several Urrga’s are seen at the one time.
This is just one of the ways of tracking turtle and dugong when the water is murky and they can not be seen through the surface of the water.