WHO WE ARE
The Essex Native Oyster Restoration Initiative (ENORI) is a collaboration between oystermen, government, conservationists and academia.
Together we are working towards the Essex estuaries having self-sustaining populations of native oysters that provide ecosystem services, increased biodiversity and sustainable fisheries whilst recognising their cultural importance. More information can be found on our partners and supporters by clicking on their logos below.
Native oysters (Ostrea edulis) are critically important both ecologically and economically.
As well as being an intrinsic part of our marine life, the native oyster provides us with many ecosystem services – these are the benefits we receive from the natural environment.
Read more about these services below:
Oyster habitats support a higher biodiversity of invertebrates and fish than surrounding unstructured habitats.
SUPPORTING FISH POPULATIONS
Oyster beds provide valuable nursery habitat for many fish species.
IMPROVING WATER QUALITY
Water quality is greatly improved by oysters filtering out suspended matter.
REDUCING NITROGEN LEVELS
Estuaries tend to have very high levels of nitrates which can be damaging to the environment. Oysters remove these excess nutrients from the water.
Native oyster fishing and cultivation have long been at the heart of coastal communities in Essex and can be traced back to Roman-times.
THREATS TO NATIVE OYSTERS
There are fewer than 5% of native oysters remaining in Europe when compared to historic levels.
This decline marks them as exceptionally vulnerable and oyster beds are the most threatened marine habitat in Europe. This is due to historic overharvesting, disease, pollution, habitat loss and competition with invasive non-native species.
To restore native oysters, we are delivering a range of solutions.
Recovering the native oyster requires a multi-disciplined approach from traditional models and local knowledge to new and innovative restoration methods. Find out more about these solutions in the menu on the right.
The Blackwater, Crouch, Roach and Colne Estuaries were designated as a Marine Conservation Zone in 2013. This 284km2 area – the largest inshore protected area in the UK – is for the recovery of the native oyster and the native oyster beds (habitat).
In 2018, the native oyster recovery management plan was formalised in the 2018 Native Oyster Fishery Flexible Permit Byelaw. This provides a mechanism to protect the oyster beds through the 200ha (2km2) Restoration Box but will also allow a sustainable oyster fishery when the oysters have recovered sufficiently.
We are collecting old oyster shell from restaurants, including from Borough Market, to re-use as cultch to help our native oysters settle and grow.
We closely monitor oyster population levels in the Marine Conservation Zone to see if oyster numbers have recovered sufficiently and are resilient enough to enable a low-level of harvesting without a long-term detrimental impact on the environment.
The University of Essex is leading research on native oyster ecology and the ecosystem services they provide. Nationally, we are contributing to research on how we can build resistance to the disease bonamiasis.
We are exploring novel, innovative financing mechanisms to find potential, alternative sources of funding for native oyster restoration.
Through working with The Nature Conservancy, we are supporting the global effort for shellfish restoration. We are also providing technical support to ZSL’s Our Sea Our Life project in Mozambique building livelihood opportunities for women through oyster ranching to reduce the pressure on the sea from fishing.
HISTORY OF OUR NATIVE OYSTER
Our native oyster has been with us for as long as we can see back in our human history.
Below is a timeline showing just how important native oysters have been to us and also some of the threats that they have faced over the years.
From the Stone Ages to the Middle Ages
Archaeological records show that native oysters have long been an important part of our cultural heritage – the Romans particularly valued them and would sell oysters along the main Roman road to London. There are even records of valuable oyster beds in the Domesday Book in 1086.
The 17th Century
Export of oysters became vital for Colchester, with peak exports in 1682 at over 4,000 bushels shipped overseas, most likely to its dominant trading partners in the Netherlands.
The 19th Century
A boom in the demand for native oysters led to 200 million being sold annually in London alone and the industry employed 15,000 boats and 50,000 people. As shipping technology improved and demand increased across Europe, the native oyster populations suffered significantly. In 1876, The Tollesbury & Mersea Native Oyster Fishery Co. Ltd was formed to enable the local oystermen to manage the oysters in the River Blackwater.
The 20th Century
Oyster landings began to plummet in England and Wales, dropping from 26 million to 7 million over 30 years to 1948.
The catastrophic freezing weather event of 1963, the introduction of the toxin Tributyltin into waters in 1980 and the emergence of the parasite Bonamia ostreae in 1983 all led to even further declines in oyster numbers. In 1979, oystermen formed the Blackwater Oystermen’s Association to jointly manage and cultivate the several order and in 1984, acquired the controlling interest in the Tollesbury & Mersea Native Oyster Fishery Co. Ltd and began the slow process of increasing oyster stocks
The 21st Century
Essex Native Oyster Restoration Initiative is formed in 2011 and in 2013 The Blackwater, Crouch, Roach and Colne Estuaries MCZ is designated for the native oyster and their associated beds. Further protection was granted in 2018 through a Kent & Essex Native Oyster Permit Byelaw, confirming the legal protection of the fisheries management plan and Restoration Box. Physical restoration in the Restoration Box began in mid-2019.
SCIENCE AND RESEARCH
ENORI AND OUR PARTNERS ARE CURRENTLY UNDERTAKING COLLABORATIVE RESEARCH PROJECTS BOTH IN THE LABORATORY AND ON THE WATER
Below is a short summary of some of the work that is being done to help the evidence-based restoration of the native oyster in the Marine Conservation Zone.
All pictures were generously provided by the ZSL Digital Team, KEIFCA, Alice Lown and The Tollesbury and Mersea Oyster Company