Authorities believe a 46-year-old woman has likely been bitten on the foot while swimming in the ocean in Western Australia's South West.
The Department of Primary Industries and Regional Development is investigating the possible shark bite off Gracetown.
It is understood the incident happened while the woman was swimming in a weedy area about 50 metres offshore, just north of Melaleuca Beach in Cowaramup Bay.
A witness observed the woman walking ashore with bite marks on her foot.
The shark was not sighted.
The incident was reported around 10:30am WA time.
The beach has been closed.
