In a rare and unexpected occurrence, Kangaroo Island tour guides Terry Pearce and Gary Bell observed two large whales off Penneshaw on Saturday, March 9.
There was one large whale and one smaller, possibly a juvenile, according to Tony Bartram from KI/VH Dolphin Watch.
As there were no images taken, the sightings were logged at the SA Whale Centre as "unidentified", but both Terry and Gary were experienced whale spotters, he said.
Mr Bartram urged people and in particular boaters to please be aware and to slow down around marine mammals.
"Please take care as these "anomalies" in normal seasonal patterns will become more frequent as changes occur in climatic conditions," he said.
The Marine Mammal Interaction Policy specifies the necessary precautions to be adhered to in case of an encounter and can be accessed on line, he said.
Whale sightings can be logged into the SAWC and the SA Museum on www.sawhalecentre.com or by calling 8551 0750.
"Efforts are currently being made to introduce speed restrictions in specific inshore coastal areas and critical habitats to minimise impacts upon marine mammals and cetaceans in particular," he said.