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Oyster farming in the Algarve

By Helga H. Hampton [email protected]

German born Helga H. Hampton first came to the Algarve with her three children in 1972. After she and her husband retired, they became residents here and have been living in an old quinta in São Brás for 10 years. Helga has always been involved with music and was President of the Associação Amigos de  Música de São Lourenço for 10 years.

Aquaculture of the ostra crassostrea gigas is thriving on our coast. There are oyster beds now in most tidal marshlands like the Ria Formosa (Olhão, Tavira, Ilha Culatra, Cacela Velha) and further in the West, for example, in the Vale da Lama near Odiáxere where at the Viveiros Ostricolas Ostra Select Rui Ferreira let me have a look into this fascinating trade.

The tide was low, I donned high rubber boots and out we marched to the endless rows of what looked like neatly arranged cushions on high-legged benches.

They were actually rugged mesh sacks with ever increasing holes filled completely with oysters of ever increasing size.

In the Algarve, it takes one to one-and-a-half years for an oyster to be fully-grown. In France, it takes up to four.
In the Algarve, it takes one to one-and-a-half years for an oyster to be fully-grown. In France, it takes up to four.

Oysters are propagated from seed. Yes, oyster seed, called “cultch” (Rui imports that from France), are filled into fine-mesh sacks and deposited on these benches in the marsh. 

A juvenile oyster is between 2mm to 6mm in size and here in the Algarve it takes one to one-and-a-half years for an oyster to be fully-grown, i.e. reach the expected marketable weight of ca. 65- 90gr.

This process and period, as well as the final size and appearance of an oyster, depend on the quality of water and ambient temperatures.

In France, for example, it takes up to four years for an oyster to be fully developed. One reason why (unbeknownst to most French oyster consumers) the largest French aquaculture enterprise grows a substantial part of their production in Algarvean waters. Only for export to France!

As the oysters grow in their appropriate sacks, nature makes the selection by sorting out weaknesses and strengths.

On mechanical sifting machines, the faster growing ones are separated from the smaller ones and put into the next size mesh sack before being returned to their marine beds – the debris is discarded. 

This process is repeated until the oysters are fully grown. It is back-breaking work, for these sacks are heavy. In Ostra Select, there are 80 rows of 200m long beds (total 16 km), each row holds 50 sacks and there are five to six handlers.

All bivalves are highly sensitive to quality of water. They feed on microscopic phytoplankton that can sometimes produce naturally occurring marine biotoxins.

As these can cause serious and even fatal illness when consumed, here in the Algarve meticulous supervision is done by the State run laboratories IPIMAR, who take weekly analyses.

And even though it was very disappointing and inconvenient for many a restaurateur, it is good to know that there were two weeks this April when sales and consumption of all mariscos, including oysters, was forbidden due to an invasion of biotoxins.

Supervision is very strict and, fortunately, this does not happen every year, but the underlying reason this year was the erratic weather pattern; the unseasonably high temperatures in March had brought marine bio-rhythm and vegetation out of kilter.

Climate change has a lot to answer for even in this “industry”.


Here in the Algarve there is no end to the oyster season – in fact, there is NO seasonal passing of oysters not even when the “Rs” vanish from the months.

That is one of the many myths surrounding the bi-valves.  This myth is grounded in practical reasoning: as oysters procreate in the summer months (in our hemisphere those without an “R”) they are then not as fat, hence the interruption of commercial marketing.

But they certainly are not inedible during this period – it is all just a matter of taste. Some people even prefer the sweeter taste of a lactating oyster.

When the male oysters grow milky once a year, the opposite gender can incubate up to one million larvae.

Their frisky “love life” is very interesting: some oysters repeatedly change their gender from male to female and back, giving rise to yet another myth that eating oysters lets one experience the masculine and feminine sides of love.

The better known myth that eating raw oysters increases libido is somewhat borne out by scientific fact.

Oysters contain dopamine, a neurotransmitter that helps govern brain activity and influences sexual desire in both men and women, and local wisdom has it that oysters are the Viagra dos pobres.

It is no myth to say that oysters are beneficial to your health. They contain high levels of zinc, complex sugars and proteins. Omega 3 fatty acids, copper and vitamins E and B12 are complemented by low calories and low saturated fat content.  

But is this really the reason why we oyster aficionados swoon by the smell and sight of these primeval looking rocks with their hermetically well-kept inner secrets?

No, ‘tis the unique taste.

“Fat and full of those contradictory flavours that are so difficult to decipher and describe. I lazily revert to sweet, briny and ozone, but that doesn’t begin to cover the complexity of an oyster,” says AA Gill, and I could not say it any better.


Eat them raw on a half shell with a squeeze of lemon juice, wine vinagre with finely chopped shallots (my favourite way), Tabasco and/or chilled vodka.

Alternatively, you can either poach them in their own juices, fry them in batter, bake them or (yucks!) make a soup.

The opening requires some practice. You need a strong, thick bladed, especially designed knife with which to pry the scrubbed oyster open.

Protect your hand, hold the oyster cupped side down, insert tip of knife in the middle and twist knife to pop open the shell.

Gently slide a finer knife along the inside to loosen the muscle which will release the shell. Don’t discard the juice. Bom proveito!

P.S.: The latest news from Rui: As of 2012 we shall benefit from the crop of the newly seeded genderless cultch ostra triploede. These seedlings are neither masculine nor feminine and will thus not procreate but stay plump and fat all year round. Another thank you to genetic engineering.