Foreign clam found at Tasmanian river

A soft-shell clam native to the northern hemisphere has been detected at a Tasmanian river, prompting an investigation.

An introduced soft-shell clam has been found on a Tasmanian river beach following a storm, prompting an environmental investigation.

The northern hemisphere's mya japonica species may have been present in the Prosser River, Orford, for a while as a shell was found in the area in 2013, although a subsequent survey was unfruitful, the Tasmanian government said in a statement.

The exact source of the incursion is not known and investigations are ongoing, the statement said.