The crew of the Vital Spark harvest oysters from Loch Ryan

Oyster Factfile

credit: Colin Tennant

Did you know...?


The Native Oyster (Ostrea edulis) is also known as the 'European' Oyster or the 'Flat' Oyster and it has been fished from UK waters since Roman times.


Oysters clean seawater, which improves water quality and clarity. A single oyster can filter around 200 litres of seawater every day. 


Oysters remove excess nutrients from water, such as nitrogen, which in large quantities can cause harmful algal blooms. 


Oyster reefs support a higher biodiversity of species than the surrounding seabed and, similar to coral reefs, these biogenic reefs provide valuable habitat for a wide range of marine species. 


Famously, the native oyster is only available for sale during months that contain the letter ‘R’ - so from 1 September to 30 April. This avoids fishing during the oyster’s breeding season.


Native oysters begin life as male, then – upon reaching sexual maturity at around two to three years of age – they spawn, following which they switch to females, capable of producing eggs.


A female oyster of around 8cm in size is capable of producing 1 million larvae in a single spawning event.


The native oyster is almost always wild and it takes a long time to develop to market size. Loch Ryan oysters are slow to grow, and are around 6 to 8 years old by the time they are harvested. 


Oysters deserve the status of superfood as they’re extremely high in vitamin B12, and zinc, contain 8 times more iron than chicken and contain omega-3 fatty acids.


Legend has it that Julius Caesar once wrote that Loch Ryan oysters are the best in the world!