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Native Oyster

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Native Oyster


Native oysters are highly prized but across their range they are becoming more and more rare. The stocks of native oyster in Falmouth and the Helford estuary are healthy and in Falmouth the Truro River Oyster fishery (whch produces Fal Oysters) is uniquely managed through a bylaw that has effectively frozen the fishery in time by banning the use of motors so that oyster are still collected using traditional sailing and rowing vessels. This makes Fal Oysters highly sustainable as well as a world famous delicacy.

Sustainability Overview

This low impact artisanal fishery is a great example of a the preservation of shellfish stocks through a simple ruling that has also preserved a traditional way of life and created a niche fishery product that has high marketing value. Fal oysters can only be caught under sail and oar.

The fishery is managed by Cornwall IFCA. Landings of native oysters decreased to a very low level in the winter of 2018 /19 but this was reportedly due to traditional continental markets not wanting the oysters. There is real need to improve marketing of the oysters and to create a domestic market for them 

Updated December 2020

Sustainability ratings for this species

Sail and Oar

Truro river and Fal Estuary

Sustainably harvested using lightweight dredges that are towed by traditional sail boats and rowing boats. The unique management of this fishery has resulted in a sustainable harvesting regime that has kept stocks healthy for 150 years.

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How we rate fish

Cornwall Good Seafood Guide rates fish on sustainability using a scale of 1 to 5.

1, 2 and 3 are recommended, Fish to avoid are rated 5.

We use the system devised by the Marine Conservation Society (MCS) so our scores are comparable with the scores produced by MCS for the UK and fisheries from all around the world. For more information on scoring click here.


The native or flat oyster is a filter feeding, bivalve mollusc. They live on the seabed in relatively shallow coastal waters and estuaries (from the lower shore to 80m). They prefer habitats sheltered from strong wave action which tend to be muddy, but require something hard for larval settlement - usually shells or stones. All native oysters start out as males, and throughout their lives change back and forth from male to female. In Britain, breeding normally takes place in the summer. It reaches maturity at about 3 years old. The average reproductive size for the oyster is about 5cm. Oysters can reach a shell length of up to 11cm, and occur in variable shapes. Native oysters have a rough shell that is yellow, pale green or brown in colour, sometimes with bluish, pink or purple markings. The two halves of a native oysters shell are different shapes. The left shell is deeply concave and fixed to the substratum, the right being flat with rougher edges and sitting inside the left, acting as a lid. Inner surfaces of both valves or shells are smooth and usually pearly, white or bluish-grey, often with darker blue areas.The shell shape is a good way to distinguish native oysters from Pacific oysters, which were introduced to the UK in 1926, and which compete with the native oyster for space and food. Native oysters have rounder shells with smoother edges, while their Pacific relatives have a more elongated shell with deeply grooved edges. A single female oyster can produce 2 million eggs. Although usually up to about 11cm long, native oysters can grow to more than 20cm and can live as long as 20 years.

Stock Info

From CEFAS lower Fal and Percuil – The harvesting of native oysters (O.edulis) and pacific oysters in the the Fal Estuary for commercial purposes is an activity with more than two centuries history.  And it is the last remaining commercially viable native oyster fishery in the UK.
Despite the decline in the native oyster fisheries seen in the past for which Bonamia, pests, competition from slipper limpets chemical contaminants and TBT had contributed, the small fishery using sailing dredgers and hand dredging has been recovering in Carrick Roads (Walmsley and Pawson, 2007). 
Since 2014 the fishery has been managed by Cornwall Inshore Fisheries and Conservation Authority (CIFCA), they carry out annual surveys of the fishery.
Landings of native oysters declined in the winter of 2018 /2019 due to decreased demand for oysters from traditional french markets. large numbers of oysters (11,000 tonnes ) were placed on lays to grow on that season. There was an increase in landings of queen scallops which allowed the fishery to remain profitable. 


The Truro River oyster fishery (producing Fal Oysters) is unique in its management, in that oysters can only be harvested using sail and oar power and dredges can only be hauled by hand. This is the only fishery of its kind and the ovrall effect has been to limit the fishery by making it more inifficient. In the recent article by Long et al (see references) this is argued to be the cause of the long term sucess of this fishery in comparison to other less sustainable fisheries. The fishery has recently become the responsibility of Cornwall Inshore Fisheries and Conservation Authority. In the Helford the shell fish beds are managed through a several order effectively making the stocks and beds private. The minimum size of oyster which is harvested is determined by the fishery byelaws, only oysters which hang on a ring of 2 5/8th inch (equivalent to 66.3mm) diameter can be harvested and oysters which pass through the ring must be put over the side of the boat back onto the fishery, or put onto oyster lays - areas on the very low shore set aside for oysters to be stored.

Capture Info

Native oysters from the Truro river (Fal) oyster fishery are caught using low impact and heavily restricted methods. Lightweight dredges (without teeth) are pulled over the oyster beds and are hauled by hand. They are also farmed on oyster beds or 'lays'.  The oyster beds have been fished in this way for centuries and the impact on the seabed is minimal. Oystermen say that dredging actually helps the oysters to grow by reducing sedimentation and removing excessive seaweeds and predators such as spiny starfish. 


Classification of bivalve mollusc Production areas in England and Wales, Sanitary Survey Report) Fal estuary(lower) and Percuil river 2012 CEFAS Kershaw and Campos
COUNCIL REGULATION (EC) No 510/2006 on protected geographical indications and protected designations of origin “Fal Oyster”  

Recipes for Native Oyster

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