NORA and UK-Ireland Native Oyster Network develop monitoring guidelines for oyster restoration in Europe

Workshop report

The UK-Ireland Native Oyster Network (UK-Ireland NON) hosted a workshop in December 2019 at the University of Portsmouth, bringing NORA and UK-Ireland NON network members together to discuss and compile metrics and methods for monitoring native oyster habitat restoration projects. They were joined by Dr. Simon Reese, from The Nature Conservancy, Australia, who has been developing similar documents for restoration of oyster reefs in Australia.  

NORA and UK-Ireland NON are working together to develop monitoring guidelines with the aim of 1) improving knowledge exchange and lessons learned regarding appropriate sampling methods between projects, 2) enabling standardized reporting of restoration progress by projects across Europe. The monitoring guidelines are designed to be appropriate for habitat restoration projects, and did not explore stock assessment and fisheries management protocols. 

A proposed structure to the monitoring guidelines was shared with workshop participants in advance, and was based on the 2016 guidelines produced by Baggett et al. (Handbook.pdf) for U.S. based oyster projects. Participants of the two day workshop prepared in advance information relating to their own sampling protocols and following a series of informative presentations, the metrics included in the US guide were considered in turn. Through group discussion, consensus was reached regarding the applicability of each metric, as well as proposals for additional metrics in the European context. Applicable, tested, methods were then proposed for each of the remaining metrics, along with a proposed unit of reporting.

The following metrics were agreed to be “Universal”, meaning that ideally all restoration projects would be able to report these metrics to allow for an overview of restoration progress across Europe: Project footprint, oyster reef area, reef height, substrate type and area including cultch cover, and oyster density. The monitoring guidelines will also include recommended “Universal environmental metrics” which should be monitored in order to understand the possible conditions that may result in restoration progress being greater or less than anticipated. “Ancillary monitoring considerations” were also developed based on the U.S. guidelines, but expanded to include further consideration of the presence and possible impact of invasive species and oyster diseases with the greatest impact in Europe, as well as sedimentation, which can be significant threat in many coastal waters in Europe.

The motivation to restore oyster reefs in Europe is diverse, ranging from the protection and restoration of the threatened and declining species and habitat itself, to ultimately restoration populations to levels where areas can be sustainably fished, or to improve water quality. Where restoration has a specific goal it is best to measure progress towards that goal directly, especially in the case of the native oyster, where many of the potential benefits of restoration are, as yet, unquantified in Europe. To this end, a series of “Restoration Goal-based metrics” were also developed to address broodstock and oyster population enhancement, biodiversity enhancement, interactions with adjacent habitats, water quality improvements, socio-economic benefits and blue carbon. 

The networks will be working together to complete and publish the monitoring guidelines in the Autumn of 2020. It is still possible to get involved. Please contact the NORA Secretariat for further information. 

The workshop was funded by the University of Portsmouth, EU Life Project, John Ellerman.

If you are interested in participating in or hosting future NORA workshops on other topics, please contact the NORA Secretariat at