At the Fishery, we are in the process of regenerating our native oyster stock, we have been in this process for the last 50 years if not longer, but that’s oyster farming for you.
The native oyster population in Europe has declined by over 95% in the last 200 years, and the native oyster has now joined the global list of endangered species.
In 1851 the journalist Henry Mayhew estimated that half a billion oysters were sold a year at Billingsgate fish market! Five hundred, thousand million oysters, we find that number hard to fathom, we have millions of oysters in our river, but that is our stock for the next four years made up of rocks, natives and broodstock.
The decrease in the native oyster population is down to many factors including overfishing, disease, the weather, pollution and the fragility of the native oyster itself.
We have lost our entire native oyster stocks several times. The great winter of 1963 saw our seawater river freeze over, and the cold water temperature killed the oysters. In the 1980s a parasite called bonamia killed oysters just as they reached breeding age and a chemical called TBT that was prevalent in the bottom paint of boats also proved fatal to oysters and other shellfish. Each time we have lost the native oysters we have had to start over with baby oysters, called spat, the size of your thumbnail. We scatter the spat into the water above the oyster beds that we have prepared with clutch - crushed oyster shell.
To further complicate native oyster farming, natives take four years to grow to a saleable size, while rock oysters take half the time. For us, growing native’s is a labour of love, it’s something that’s in our blood, for it makes no financial sense to keep persevering with this tricky oysters.
There has been a considerable increase in popularity for the native oyster since going on the endangered species list. Not only to save the species, as a food source, a livelihood and because they are delicious but because we have discovered just how vital oysters are for the marine environment. An oyster will filter about six litres of water a day, which helps to clean the water. Oyster shells are made up of calcium carbonate which fixes carbon into the seabed when the shells degrade, helping to reduce carbon dioxide in the sea.
We are working closely with the scientists and PhD students at the University of Essex and the Essex Native Oyster Restoration Initiative to restore the native oyster into the river. The aim is to create a self-supporting native oyster population that will allow native oysters to thrive so we can keep enjoying these incredible oysters.
We have reached the end of our native oyster stock for this year, about a month early, which was good going using our own native oysters from the Pyefleet. We would have had more, but the heatwave in the summer of 2018 was too hot for a lot of our juvenile oysters, and we lost a lot of stock. For the remainder of the native oyster season, we will be selling native oysters from our friends in Whitstable.
If you would like to learn more about the Essex Native Oyster Restoration Initiative, you can find their website below and also a link to the nationwide native oyster network who connect the native oyster restoration projects, production companies and oyster farms like us.