The battle against a little-known but potentially destructive invasive oyster is well underway, but authorities say it’s Aussies on the water who will make or break the fight. The species, newly spotted in Queensland, could spread rapidly unless the public stays vigilant and reports sightings.
Suminoe oysters were recently found in estuaries near Moreton Bay, and despite being able to grow bigger than human hands, they are difficult to distinguish from native species due to their similar colourations until they mature.
The fast-growing species can reach up to 24 centimetres in length and attain sexual maturity within three months, with some individuals ready for harvest in as little as 15 months — far quicker than the two-and-a-half to four years it takes for a native Sydney rock oyster.
In an interview with Yahoo News Australia, Dr Carol Booth said that as this invasive species quickly and quietly spreads across northeastern parts of the country, the public will play a crucial role in the fight back.
“It’s really up to the public. They’re the eyes out there, so if they find oysters they suspect are this oyster, they should report it, take a photo, and then report it to Biosecurity Queensland,” she urged.
“The other thing is to be really careful — boat owners really should be checking and cleaning, making sure their equipment and boats are clean and not spreading this species or other species. Boat owners have a big responsibility because that’s the way a lot of marine species can be spread. That message to both owners is really important.”
The fast-growing species can reach up to 24 centimetres in length and attain sexual maturity within three months. Source: Queensland DPI
What risks come with introduced species like the Suminoe oyster?
Dr Booth believes that, because they’re edible and cultivated overseas, it can also reasonably be suspected that “a human might have brought them in”.
She said because they grow so rapidly, they’re likely to be able to outcompete native oysters, too.
“The actual effects [of their spread] will play out in time, but the other really concerning aspect of when something like this arrives is whether they have any pathogens with them that are going to escape, jump hosts, and infect our native species,” she warned.
The species, newly spotted in Queensland, could spread rapidly unless the public stays vigilant and reports sightings. Source: Queensland DPI .
“It’s always a worry when things come in accidentally or illegally. What happens if they do have those pathogens? Depending on whether native species have ever been exposed to that pathogen or closely related ones, if they didn’t have that exposure, they’re likely to be highly vulnerable to disease.”
Unlike Australia’s Sydney rock oyster, which supports a long-standing aquaculture industry, the Suminoe oyster forms dense, aggressive reefs that smother seagrass beds and displace native marine life. Scientists warn this could erode biodiversity, reduce water quality and damage the natural habitats that fish and crustaceans depend on.
The Suminoe oyster forms dense, aggressive reefs that smother seagrass beds and displace native marine life. Source: Queensland DPI
The species also poses a direct economic threat. In other parts of the world, it has been linked to the spread of parasites and pathogens, and its dominance makes it harder for native oyster farmers to maintain stock. On top of that, its razor-sharp shells can litter shorelines, creating hazards for swimmers and beachgoers.
Dr Booth explained that, in Australia, we’ve lost frog species because of diseases like chytridiomycosis, caused by the introduced chytrid fungus. “And we’ve got fish diseases brought in on aquarium fish or other live fish that have spread into the wild,” she said.
“Increasingly, these pathogens are being circulated the world and finding new victims that have no immune response, which allows them to survive. The naivety of Australia, because we’re so isolated, means that new things coming in often find native species without any exposure and no response.”
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