Nearly 20 tonnes of rock armour, embedded with thousands of young European flat oysters, have been deployed on two cable crossings in the North Sea. This effort is part of a pilot project led by TenneT and eight partners.
The initiative aims to test if oysters can survive, grow, and reproduce on the rock armour, potentially integrating this method into maritime infrastructure projects.
TenneT uses rock armour to shield subsea electricity cables at infrastructure crossings, and rock is crucial in offshore wind farm construction and maintenance.
The consortium explores if rocks can be seeded with oysters offshore, creating “oyster stones” that blend cable protection with nature restoration.
For the trial, partners converted shipping containers into mobile hatcheries, applying a method called “remote setting.” Oyster larvae were transferred from a hatchery to a sea-adjacent site, where millions attached to rocks in seawater-filled containers.
The oysters grew to several millimeters over several months before the rocks were moved offshore to the cable crossings.
This deployment is the first test in open sea conditions, following a preliminary trial last year in the Port of Rotterdam, where researchers studied oyster survival and growth.
Adjustments included stabilizing temperature and food supply in hatcheries, enhancing oyster spat settlement on each rock.
Oyster survival will be monitored through various stages, including land and sea transport and placement on the cable crossings, to determine their success in open sea conditions over the next year.
Flat oyster reefs once thrived in the North Sea but have mostly vanished due to overfishing, pollution, and disease. The project partners believe reintroducing native oysters could support new reef development.
“TenneT will realize many new offshore wind farm connections soon. As we develop North Sea infrastructure, it’s crucial to embrace opportunities that bolster marine ecosystem conservation and restoration,” said Marcel van Veldhuisen, Spatial and Environmental Strategist at TenneT. “This experiment offers valuable insights into contributing to large-scale nature restoration in the North Sea.”
Participants include Wageningen Marine Research, Wageningen University, Stichting Zeeschelp, ARK Rewilding Netherlands, TenneT, Van Oord Ocean Health, The Rich North Sea, Waardenburg Ecology, and the Port of Rotterdam Authority.
Van Oord has engaged in various Dutch offshore oyster restoration projects. At the Borssele V offshore wind farm, Van Oord installed oyster reef structures as part of a research initiative on establishing European flat oysters on offshore scour protection, collaborating with Eneco at the Luchterduinen offshore wind farm.
Original Story at offshorewind.biz