Public asked to avoid the area
A whale carcass has led to the the discolouration in the tidal pool near Groudle Glen, the Department of Environment, Food and Agriculture has confirmed.
Pictures had surfaced on social media showing copper-coloured swirls in the water at Sea Lion Rocks.
The authority says it's likely the remains were washed in by a high tide, and it is hoped it may be dispersed with upcoming spring tides.
In the meantime, the public are being advised to avoid the carcass as a matter of health and safety.