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ESSEX NATIVE OYSTER RESTORATION INITIATIVE

 
 

THE NATIVE OYSTER

has lost 90% of its original range

 
 

RESTORATION

of one of the most threatened habitats in Europe

 
 

COLLABORATION

between oystermen, NGOs, government and academia

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.

Supported by

 
 
 
 
 
 
 

ACHIEVEMENTS

Designation of the 284km2 Blackwater, Crouch, Roach and Colne Estuaries Marine Conservation Zone (MCZ) in 2013 with the conservation objective to recover native oysters and native oyster beds. More information on MCZs can be found here.
Creation of a 200ha (2km2) Blackwater Restoration Box for the specific purpose of recovering native oyster beds.
Adoption of a fisheries management plan to recover native oyster populations in the MCZ which when resilient enough will allow a sustainable fishery.
The confirmation of the Native Oyster Permit Byelaw in 2018 that protects the fisheries management plan and Restoration Box by law.
Secured a marine license for restoration activities, the first of its kind in England.
The Mother Oyster sanctuary is located in the 200ha (2km2) Restoration Box where we are translocating mature native oysters to improve reproductive success.
Established a supply chain of waste oyster shell from stalls in Borough Market, London and on Mersea Island to relay in the sea and improve the seabed for oysters to settle and grow (another UK first).
Helped establish first UK network for the restoration of native oysters.
We are undertaking ground-breaking science to support native oyster recovery.
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IMPORTANCE

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:

BIODIVERSITY

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.

HERITAGE VALUE

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.

RECOVERY

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.

HABITAT PROTECTION

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).

ADAPTIVE MANAGEMENT

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.

‘MOTHER OYSTER’ SANCTUARY

The Mother Oyster sanctuary is a 200ha (2km2) Restoration Box where we are translocating mature oysters to improve reproductive success.

IMPROVING THE SEABED

Juvenile oysters need hard substrate to settle on and grow.  We are putting back old shell and gravels as cultch onto the seabed in our Restoration Box.

SHELL RECYCLING

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.

SUSTAINABLE FISHERY

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.

RESEARCH

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.

SUSTAINABLE FINANCES

We are exploring novel, innovative financing mechanisms to find potential, alternative sources of funding for native oyster restoration.

NATIVE OYSTER NETWORK

We have been instrumental in the establishment of the UK Native Oyster Network to share best practice and drive an ecosystem-wide recovery across Europe.

INTERNATIONAL

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.

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.

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 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 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.

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.

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.

The first extensive study of oysters in Essex estuaries was conducted in 2012.  The data were used to demonstrate the importance of the sites and to underpin the application for MCZ status in 2013.
Research is underway looking at monitoring growth, survival and recruitment of oysters. This will influence the development of a predictive model for oysters to aid in fisheries and conservation management.
Further research areas include investigations into non-invasive methods to predict spawning times, ecosystem services provided by oysters and modelling stock recovery of native oysters in the MCZ.

All pictures were generously provided by the ZSL Digital Team, KEIFCA, Alice Lown and The Tollesbury and Mersea Oyster Company

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