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Ocean Tide Ventures
A freshly shucked oyster held open in the palm of a hand

The oysters

Two shells, two entirely different arguments.

Both of Malaysia's commercially important native oysters are grown for us. They are not interchangeable, and we would not want them to be.

A shucked Iredalei on the half shell, held in a gloved hand, the pale meat filling a narrow deep cup

Iredalei

Crassostrea iredalei

The small one, and the one we are asked for most. Grown on our contract sites in the sheltered bays of Sabah, it comes out deep-cupped and firm with a clean mineral finish and no heaviness at all. Restrained rather than shy. There is plenty there; it simply does not shout. This is the oyster to hand to someone who is convinced they don't like oysters.

Shell
Taller than long, fairly straight margin, thin and slipper shaped
Typical size
2.5 to 3 inch
Adductor scar
Small and pale
Meat
Firm and dense, pale, sits deep in the cup
Growth
Slower, which is why it stays small and keeps its density
Water
Sheltered coastal bays
Profile
Mineral, clean, restrained
Best served
Raw on the half shell
Four shucked Belcheri on a wooden board, the long heavy shells holding brown cream meat with a pale adductor scar

Belcheri

Crassostrea belcheri

The big one. Grown in the warm, plankton-heavy water off Sabah, Belcheri puts on size fast and fills the shell: creamy, sweet and substantial enough to stand up to heat, butter, garlic and fire. If you are grilling, this is the oyster. It also eats very well raw, provided you are hungry.

Shell
Long, heavy and deeply cupped, often crusted with algae
Typical size
4 inch and above
Adductor scar
Pale, which is what white scar oyster refers to
Meat
Brown cream, soft and full, fills the shell edge to edge
Growth
Fast, the reason it reaches grilling size in a season
Water
Warm estuarine and mangrove water, 15 to 25 ppt
Profile
Sweet, rich, generous
Best served
Grilled, baked, or raw

Telling them apart

Two species, not two sizes of the same one

People often assume the small one is just a young large one. It is not. These are different animals with different shells, different growth rates and different water, and an Iredalei will never grow into a Belcheri no matter how long you leave it on the line.

Drawn to scale

Iredalei, Belcheri and the gap between them, drawn to scale Drawn to scale. An Iredalei is 2.5 to 3 inches, 6 to 8 centimetres. A Belcheri is 4 inches and above, 10 centimetres and above, roughly one and a half times the length. Nothing we sell falls between 3 and 4 inches. Nothing we sell sits here Belcheri XL (XL, 6"+) Iredalei 2.5 to 3 inch (6 to 8 cm) and above Belcheri 4 inch and above (10 cm and above) 1" 2" 3" 4" 5" 6" 7" 2 4 6 8 10 12 14 16 cm Iredalei, Belcheri and the gap between them, drawn to scale Drawn to scale. An Iredalei is 2.5 to 3 inches, 6 to 8 centimetres. A Belcheri is 4 inches and above, 10 centimetres and above, roughly one and a half times the length. Nothing we sell falls between 3 and 4 inches. Nothing we sell sits here 1" 2" 3" 4" 5"
  • Iredalei: 2.5 to 3 inch (6 to 8 cm)
  • Belcheri: 4 inch and above (10 cm and above)
  • inches, centimetres
  • Nothing we sell sits here
  • Belcheri XL (XL, 6"+)
Scaled on inches, with centimetres as a second ruler: the two bands in the pricelist are trade figures, not exact conversions.
Character Iredalei Crassostrea iredalei Belcheri Crassostrea belcheri
The animal
Common name Slipper oyster White scar oyster, or mangrove oyster
Shell Taller than long, thin, fairly straight margin, slipper shaped Long, heavy and deeply cupped, often crusted with algae
Market size 2.5 to 3 inch 4 inch and above
Adductor scar Small and pale Pale, and it is what the name white scar refers to
Meat Firm and dense, pale, sits deep in the cup Brown cream, soft and full, fills the shell edge to edge
Growth Slower, which is why it stays small and keeps its density Fast, which is why it reaches grilling size in a season
Water Sheltered coastal bays Warm estuarine and mangrove water, 15 to 25 ppt salinity
In the kitchen and the trade
On the plate Raw on the half shell, a squeeze of lime and nothing else Grilled, baked, or raw if you are hungry
In the trade The higher value of the two in Malaysia, on taste and appearance The volume grade, and the one people picture when they picture an oyster

A note on the name Belcheri

What the trade sells as Belcheri is more than one species. Magallana belcheri, the white scar oyster, is named for the pale adductor muscle scar inside the shell. Magallana bilineata, the black scar oyster, carries a dark one. They are landed together, sold together and published together, and the standard COI barcode does not reliably separate them, which is why a meaningful share of the sequences in public databases are known to be misidentified.

Our Bambangan stock looks like the black scar type. The rest looks like the white. We have not had either genetically confirmed, so we sell the lot as Belcheri and tell you this rather than claim a precision we do not have. If that distinction matters for your kitchen, ask us and we will show you the shells side by side.

Grading

How we size and sort

Every oyster is graded by shell length after depuration. Anything undersized goes back on the line to keep growing rather than into the box. Note the gap: an Iredalei is capped at 3 inch and a Belcheri does not leave us below 4, so nothing we sell sits between the two.

2.5 to 3 inch
Iredalei, small · the half shell grade
4 to 6 inch
Belcheri, large · grilling and baking
6 inch and above
Belcheri XL · sharing plates, fire cooking
Live / hibernated
Both species ship live, chilled and batch coded

What actually came ashore

Grade mix across the published ledger Of 5,286 pieces published across 18 batches, 2,571 were Iredalei small, 1,751 Belcheri large and 964 Belcheri extra large.
Iredalei, small
2,571 pcs (48.6%)
Belcheri, large
1,751 pcs (33.1%)
Belcheri, extra large
964 pcs (18.2%)
Total
5,286 pcs
5,286 pieces landed and published across 18 batches received 25 April 2026 to 11 September 2026. This is what came ashore, not what customers asked for.
See the ledger

At the table

Getting the best out of them

01

Keep them cold, keep them closed

Store flat, cupped side down, between 2 and 8 °C, covered with a damp cloth. Never in fresh water and never sealed in plastic. They are alive and they need to breathe.

02

Shuck at the hinge

Find the hinge at the pointed end, work the knife in and twist rather than lever. Run the blade along the top shell to release the adductor, then under the meat. A folded tea towel is worth more than a fancy knife.

03

The first liquor is not the best liquor

Tip out the first liquor after shucking and give it thirty seconds to refill from the oyster itself. Cleaner, sweeter, and no shell grit.

04

Do less than you think

An Iredalei wants nothing but a squeeze of lime. A grilled Belcheri wants butter, garlic and a hot fire, and about four minutes. Anything more elaborate is usually hiding something, and there is nothing here to hide.

Beyond oysters

What else comes out of the partnership

Vertical integration means we produce more than we need. The surplus goes to other Malaysian growers, because a single farm is fragile and an industry is not.

A handful of juvenile oyster spat, each shell only a few millimetres across

Oyster spat

Triploid and diploid seed produced through licensed hatchery partnerships, graded and supplied to growers across Malaysia. Reliable seed is the single biggest constraint on this industry, and we would rather solve it for everyone.

A jar of golden microalgae culture held up to the light on a visit to GK Aqua, where algae is cultured for shrimp production

Microalgae

Live algae culture, the feed that larvae and spat depend on. Our partner cultures it at the Tawau hatchery, and we supply it onward to other growers and research programmes.

Fresh harvested seaweed

Seaweed

Grown alongside the oyster lines, where it absorbs excess nutrients and improves the water for everything around it. Used in aquafeed and as a crop in its own right.

Farm equipment and sealed shipping boxes staged for despatch

Aquaculture equipment

Through partnerships with Malaysian technology providers we supply the rack, raft, basket and monitoring hardware that a new grower needs to start properly rather than improvise.

Oyster stakes silhouetted against the water at dusk

Come and see

Stand on the raft. Then decide.

Farm visits run daily from 11:00 to 17:00, rafts, hatchery, depuration tanks and chill room, finishing with oysters shucked in front of you.