Video footage and photographs have been shared on Facebook by Bermagui commercial fisherman Jason Moyce (@Trapman Bermagui) and Bermagui Bait and Tackle, with countless comments from stunned viewers.

Fishermen in the area said it is very uncommon for the pelagic species to be in the lake and suspect it has accidentally lost its way chasing food, or perhaps is suffering an illness. 

Every year Southern Bluefin Tuna migrate with the cold water along Australia’s southern and eastern coastlines. 

The species can reach up to 2.45 metres in length and 260kg although rarely exceed 100kg in Australian waters.