Staff Sergeant Mohamed Mahdhee died while diving in the search and rescue operation, the Maldives government tells the BBC.
President Donald Trump said the operation eliminated "the most active terrorist in the world", Abu-Bilal al-Minuki.
Police and rescue officials said the collision sparked a fire that engulfed the bus.
The man was bitten just before 10:00 (03:00 BST) at Horseshoe Reef - north-west of the popular Rottnest Island near the city of Perth, local police said.
The US president says the joint operation eliminated "the most active terrorist in the world", Abu-Bilal al-Minuki.
Charges could come as soon as next week in a case reportedly focused on Cuba's downing of two planes in 1996.
Charges could come as soon as next week in a case reportedly focused on Cuba's downing of two planes in 1996.
It marks the third time a New York jury has considered the case against the 74-year-old disgraced film mogul.
President Trump announced the truce last month, but Israel and Hezbollah have continued to exchange fire since then.
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