Daphne the duck vanished from the Cockburn Masters Swimming Club in Perth on Sunday, 11 March as preparations were taking place for an annual ocean swimming competition.
“After 50 meters she was just gone, baby, gone,” Peter Marr, the club’s president, told the Australian Broadcasting Corporation of his effort to swim after Daphne, who was supposed to be the event’s star attraction. “I couldn’t keep up.”
According to local reports, the $900 (£500) duck had been purchased to mark the 22nd anniversary of the event.
The club appealed for help on Facebook in its search to find the beloved mascot.
After a week long search and reported sightings, the yellow duck was found by local fishermen 30km out to sea just off Rottnest Island in the west of the city.
Mr Gibb told the BBC he found the duck at around 06:30 - only an hour after Daphne went missing.
He is meeting Cockburn Masters Swimming Club chairman Peter Marr on Wednesday about returning the duck.