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Fancy Oysters are Fighting Tasmanian River Pollution

Oysters have long been lauded for their ability to get your pants off, but the salty little bivalves are more than just an aphrodisiac: They're also being used to filter heavy metals out of Tasmania's long-polluted Derwent River.
Photo by Moorilla Gallery

Oysters have long been lauded for their ability to get your pants off, but the salty little bivalves are so much more than just an aphrodisiac. In Tasmania, they've also proven to be eco-friendly, where oysters are currently being put to work in a project to filter heavy metals out of Hobart's long-polluted Derwent River. As you would expect of a Tasmanian-based collaboration between science and art, the project belongs to MONA (Museum of Old and New Art), whose grounds sit before a polluted patch of the river. The project is a mixture of all good things: science, art, and seafood.

Photo by Moorilla Gallery

When the oysters die after filtering the toxins, their shells are inserted into the mausoleum wall. All photos by Moorilla Gallery via Flickr.

Pollution in the Derwent is well-documented, the result of years of abuse from industrial runoff upstream. Heavy metals such as mercury, zinc, cadmium, lead, and copper are all present in deposits throughout the river thanks to large industries like the Norske Skog paper mill and the Nyrstar Hobart zinc smelter. For years, government agencies warned against eating seafood from the river, particularly shellfish, because of metal contamination. Oysters were noted for capturing large amounts of metal through their natural feeding process of filtering water, with no real negative effect on the oysters except becoming inedible. And so the idea to farm oysters for use strictly as filters instead of food was created.

Currently, just off MONA's jetty sits a small farm of 120 oysters, self-sacrificing as they suck the Derwent of heavy metals. Kirsha Keachele, MONA curator and artist, ran with the idea of oyster filtration with a couple of scientist friends to create The Derwent River Heavy Metals Project, an elaborate scientific artwork to honor the humble oyster. After their lives as environmental soldiers reaches its climax, the MONA oysters, still holding their metallic burden, are harvested, dried, and cast in concrete or glass before being added to an oyster mausoleum in remembrance of their noble work. With estimates, it would take up to 1.1 trillion oysters to extract all of the river's metals. It's certainly no quick fix, but it's a start.


According to Catriona McLeod, a scientist from the University of Tasmania's Institute for Marine and Antarctic Studies, so far so good, "It's going really well. The oysters at MONA have done better than expected, and the preliminary results show differences in performance with species. MONA is continuing to support the heavy metals project and the overarching goal of improving conditions in the Derwent, and we are looking to broaden both the collaboration and research base. But rest assured that the mighty little oyster is still in there doing some great things for the environment."


The chapel oyster massage hatchery by artist Kit Wise

The oysters used in the filtration farm are a mix of the common Pacific and native Australian Angasi—the supermodels of the oyster world, since they're difficult to deal with but spectacular in result. The Angasi are often referred to as flat oysters: They live out their lives in the silt of the riverbed, unlike the rock-based Pacific oysters that were introduced. They're not the most welcoming creatures; a life in the silt creates a smell that, when harvested, is a major buzzkill. If you do get past the stench, you can expect a fat, juicy oyster that evidence suggests even ancient Aborigines enjoyed. Philippe Leban, the executive chef at MONA, has a particular love for the Angasi. "They're not dissimilar to the Belon oyster in France, and they're a revered oyster," he says. "If you're an oyster fan, the Angasi is the pinnacle of oysters."


The Derwent River Heavy Metal Project does more than simply highlight a natural solution to the unnatural environmental problem of river pollution; it also pays homage to the role of oysters in Tasmania's food industry and culture. Tasmania oyster growers harvest approximately 38 million oysters a year—25 percent of Australia's total annual harvest. Philippe and his Michelin-starred résumé consider Tasmanian oysters to be the best in the country, "I don't often say that—I'm not here to trumpet Tasmania—but I think it's very true that the oysters here are the best in the country."

In typical MONA fashion, there's a twist of dark humor to the oyster project: Visitors are able to view the oyster mausoleum from a nearby oyster bar. While being shaded by suspended growing cages, they can feast on oyster comrades who've lived a much more pristine life. So what is the best way to serve a healthy, non-metallic Tasmanian oyster? It's definitely not Kilpatrick—try asking an oyster lover how offensive that is.


The oyster bar at MONA Gallery

"It sort of like curry, which can do two things: highlight food and mask food. And dare I say oysters Kilpatrick is one of those things that masks the flavor of the oyster. It seems to be the way to eat an oyster if you don't like oysters," says Philippe. "There are a number of ways you can serve oysters. You can broil them, but you have to be particularly careful that you don't end up with a rubbery mess. Traditionally, I've seen them served with a little slice of mushroom and a little vinaigrette, gently broiled in their own shell—sensational, just gorgeous."

Overall though, it's probably best not to complicate things. "The best way to serve an oyster is to be standing at an oyster farm, eating it out of the shell, straight from the sea. And if you've got a little wedge of lemon there, lucky you."

Make it a Tasmanian oyster farm, and you just might be the luckiest bastard around.