MARLIN washed up on Augusta beaches in recent months are unusual, but not unheard of, says the WA Department of Fisheries.
Last Wednesday a blue marlin approximately 2.5 metres long and weighing 250 kilograms was discovered dead in the water 100m south of the new marine wall in Augusta.
It was the second of its species to wash up on the beach in two months, after a 3.68m monster was found dead at the beach in early August.
Augusta abalone diver Joel Veitch retrieved the fish from the water and said it had not long been dead.
"It was a very fresh death. Apparently there were white pointer sharks nearby when we dragged it out," Mr Veitch said.
WA Department of Fisheries community education coordinator Michael Burgess said blue marlin were known to wash up along WA's south coast infrequently, though their movements are not well known.
"Abnormally warm ocean temperatures, off the west coast and south coast of Western Australia in recent years, have been favourable for tropical species to extend their distribution into southern waters," Mr Burgess said. Western Angler fishing magazine editor Scott Coghlan said tropical fish may get caught in warm ocean currents.
"They get caught in a pocket of warm water which dissipates in the colder southern waters, and then they can't survive the conditions," Mr Coghlan said.
Mr Burgess said there is currently no evidence to suggest the fish have died of anything other than natural causes, though the department is collecting data on reported marlin beaching, which he said have been frequent in 2013.
Along with the two in Augusta, there was one confirmed beaching in each Denmark and Albany, as well as one as far east as South Australia.
Mr Burgess said he encouraged anyone who finds an unusual or out of place species of fish to log the find on the department's database at redmap.org.au.