Suzanne's Mom's Blog

Photo: Rory Carroll/The Guardian.
Aoibheann Boyle and Andrew Collins inspect oysters at the Green Ocean Foundation’s project in Dún Laoghaire harbor. 

I don’t have a traditional Irish story to offer for St Patrick’s Day, but today’s article may get you singing about sweet Molly Malone and her “cockles and mussels, a-live, a-live-o.”

That’s because Ireland is doing some interesting work with shellfish. Rory Carroll of the Guardian reports from Dublin’s Fair City about an oyster graveyard rising from the dead.

He begins, “The dinghy slowed to a stop at a long line of black bobbing baskets and David Lawlor reached out to inspect the first one. Inside lay 60 oysters, all with their shells closed, shielding the life within. ‘They look great,’ beamed Lawlor. So did their neighbors in the next basket and the ones after that, all down the line of 300 baskets, totaling 18,000 oysters.

“They are, however, never to be eaten. Instead they are tasked with reproducing and restoring oyster reefs to Dublin Bay more than two centuries after they were wiped out. …

“Similar restoration projects are unfolding elsewhere in a continent that once had sprawling reefs of the European flat oyster (Ostrea edulis) until overfishing, dredging and pollution wreaked obliteration.

Reefs create rich ecosystems, provide a habitat for almost 200 fish and crustacean species and play a vital role in stabilizing shorelines, nutrient cycling and water filtration.

“ ‘These oysters are amazing climate heroes,’ said Lawlor, co-founder of Green Ocean Foundation, a nonprofit that is driving efforts in Dublin. ‘They are natural filter feeders. Each oyster filters at a rate of 190 liters [~200 quarts] of seawater a day.’

“By feeding on plankton and nitrates, the oysters clear algae and help sunlight to reach the seafloor, boosting sea grass – a carbon sink – which in turns helps other species and improves coastal biodiversity and marine habitat.

“Ireland’s inhabitants cultivated oysters in the middle ages but in the 1800s industrialization and overfishing killed off the Dublin Bay reefs – a phenomenon replicated from Scandinavia to the Mediterranean.

“Inspired in part by New York’s Billion Oyster Project [see my blog post here] Lawlor enlisted volunteers and business sponsors for pilot projects that moved oysters from Tralee Bay in County Kerry to sites in Malahide, Howth, Poolbeg and Dún Laoghaire, which ring Dublin bay, and in Greystones, in County Wicklow.

” ‘You’re building your understanding of why things work well or don’t work well. You want to make sure they survived, to see what the growth was like, and to see if they spawn,’ said Lawlor. The transplanted oysters fared especially well in Dún Laoghaire so it was chosen for the next phase of the project. …

“Scientists from Dublin City University’s Water Institute analyzed the water last year for baseline indicators and will monitor the oysters’ impact with sensors and chemical and biological assessment.

“The baskets are connected along a 100-metre line and are flipped by hand every few weeks to let Arctic terns, gulls and other birds peck away fouling that might otherwise curb the flow of water through the baskets.

“In Northern Ireland, the charity Ulster Wildlife used a different technique recently to place 2,000 adult oysters and 30,000 juveniles, sourced from Scotland, on the Belfast Lough seabed.

“The Luna Oyster Project, a collaboration between Norfolk Seaweed and Oyster Heaven, aims to restore 4 million oysters to the North Sea by using the first mass deployment of clay structures called mother reef bricks.

“The Dublin initiative is far smaller but will hopefully grow, said Lawlor. ‘The temptation is to think massive but you need to take one step at a time. A lot of the challenge is bringing people with you,’ he said, citing government departments, local councils, wildlife groups and harbor authorities.”

More at the Guardian, here.