Gabion oyster fence

OzFish Unlimited is innovating the shellfish revolution with the upcoming trial of Quilted Oyster Doonas (QODs) set to bring an added layer of versatility to restoration projects.

Robbie Porter, OzFish’s Senior Special Projects Officer – Shellfish Revolution, who invented the QOD, said: “No one has ever done something like this before, and we think it could be really useful.”

The home-grown invention uses a non-degrading, flexible gabion blanket that incorporates recycled oyster shells, which can be securely attached to rock walls, eroding banks, and urbanised waterways, effectively transforming these structures into vibrant living seawalls.

“Effectively, they are stainless-steel chicken wire that we make an envelope out of and put shells inside it. To stop all the shells falling to one end, we quilt the chicken wire, so the shells are spread out evenly, much like duck down in a doona,” Mr Porter explained.

The project should increase biodiversity and improve water filtration, bolstering fish numbers in the river.

One key aspect of their expected effectiveness lies in using recycled and sanitised oyster shells. The complex nature and chemical signature of these shells make them highly attractive to spat (baby oysters), or young shellfish, thereby serving as an ideal substrate for shellfish recruitment.

OzFish plans to mobilise its army of volunteers to make the QODs with councils and civil engineers expected to use them in future projects.

“There will be a lot of hidey-holes for ambush predators. They’ll give lots of overhanging spaces for invertebrates like sponges, limpets, crabs and worms to hide in,” Mr Porter added.’

This story was first published in THE FENCE magazine.