In 2013, the 284km² Blackwater, Crouch, Roach, and Colne Estuaries Marine Conservation Zone was designated to recover native oyster populations and native oyster beds. A protected 2km² Blackwater Restoration Box was created as a No Take Zone for the Essex Native Oyster Restoration Initiative (ENORI) to trial active restoration management, with the specific purpose of recovery of native oyster beds.
In order to facilitate recovery, ENORI are undertaking active habitat restoration by increasing the availability of stones and shells within the Restoration Box. These hard substrates, known as ‘cultch’, are the perfect habitat for juvenile native oysters to come and settle on during their larval stage.
Active restoration began in 2019 with small scale trials of gravel and different shell types. From these trials, settlement of juvenile oysters was seen on the gravel and all shell types, with the highest settlement rates seen on scallop and mussel shell. Therefore, plans were made to scale up the restoration efforts and focus on deployment of the more productive materials. In 2020, ENORI received a National Lottery Heritage Fund grant to scale up restoration and outreach efforts.
In 2021, over 7000m2 of seabed was actively improved by cultch deployment. Since this deployment, monitoring results have shown an increased biodiversity on the deployed cultch compared to control areas, as well as good settlement of native oysters. This large-scale restoration work has continued this year, with a further 900m3 of cultch deployed to double the size of restored habitat.
Monitoring work will continue this year, and restoration and outreach updates from ENORI can be found regularly on ENORI’s social media accounts via @EssexOyster
