MARINE experts have been left scratching their heads after a dead 120kg swordfish was found washed up on Sunrise Beach.
Locals spotted the 2m long billfish at Burgess Creek and alerted local councillor Russell Green who said he would "let the work gangs know".
Council workers buried the creature at the beach on Monday afternoon but not before poachers used a hacksaw to cut off its long bill as a trophy.
The fish's death has remained a mystery since there were no obvious signs of trauma. Experts said the presence of billfish in shallow water was a rarity.
Author and marine biologist Dr Julian Pepperell, from Doonan, said the death was odd.
He offered two scenarios.
The fish died of natural causes at sea and simply drifted ashore.
He said swordfish had large bladders and dead ones can float long distances.
"They do get washed up during storms," Dr Pepperell said.
The other possibility was that it simply swam too close to the beach and recent stormwater suffocated it.
"Dirty freshwater is deplete of oxygen," he said.
Sunshine Coast Game Fishing Club president Brent Higgins said the death did not make sense.
"I would imagine this fish was unhealthy to end up here and it didn't look damaged in any way from lines, props or sharks," Mr Higgins said. "Very few are seen inshore."
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