Eco-menace clam invader sparks alert

TASMANIA has a new, unwelcome visitor with the potential to alter our marine environment forever.

Authorities have been alerted to the discovery of a softshelled clam on a beach at the Prosser River recently.

Soft-shelled clams or sand gaper clams ( Mya arenaria) are a species of edible saltwater clam and the Tasmanian discovery is understood to be the first in the southern hemisphere.

They are considered a marine pest risk because of the species’ potential to out-compete native species and modify local marine environments.

Department of Primary Industries, Parks, Water and Environment (DPIPWE) is urging people who find specimens not to collect or move the molluscs, which compete with native species.

Primary Industries Minister Sarah Courtney said the department would work with the local seafood industry to see what eradication or control measures could be used.

“There are indications that these clams, which are native to the northern hemisphere, may have been present in the waterway for some time,” Ms Courtney said.

“A Mya shell was found in the area in 2013 but a subsequent survey did not locate any further specimens. The exact source of this incursion is not known and investigations are ongoing.”

DPIPWE and Biosecurity Tasmania are consulting with the local seafood industry and seeking expert advice from the Institute for Marine and Antarctic Studies.

Soft-shelled clams can grow up to 150mm in width and typically live buried in intertidal and subtidal zones in sand, mud and gravel.

The clam was discovered following a storm and flood that exposed tidal mudflats in the Prosser River.

The shell was taken to the Tasmanian Museum and Art Gallery for identification and the museum contacted Biosecurity Tasmania.

Biosecurity officers visited the site and found live specimens.

The Commonwealth Government chief veterinary officer was notified as part of agreed protocols and late last week the genetic analysis confirmed the species as Mya japonica.

Last Friday, the national Consultative Committee on Introduction of Marine Pest Emergencies met in accordance with the Australian Emergency Marine Pest Plan to consult other jurisdictions.