A comprehensive guide to molluscs – bivalves

Bivalve molluscs

What are bivalve molluscs?

Bivalves are a class of molluscs that have two, usually similar, shells connected by a flexible ligament. Clams, mussels, oysters, cockles and scallops are the most commonly consumed kinds of bivalve molluscs. Like fish, bivalves breathe through their gills – and as filter feeders, they also gather food through their gills. Some bivalves have a pointed, retractable ’’foot’’ that protrudes from the shell and digs into the surrounding sediment, effectively enabling the creature to move or burrow.

How important are bivalves to marine ecosystems?

Many bivalve species play important roles in aquatic and marine ecosystems by filtering the water and serving as habitat and prey for a variety of sea life. This diverse group of species (estimated at about 9,200 different types) inhabits virtually the entirety of the world’s coastal waters.

Scallops (Pectinidae)

How are scallops harvested and stored?

Good quality frozen scallops are harvested then immediately individually quick frozen. Just before they are frozen they are glazed with water, which forms a barrier of ice that protects from freezer burn.

How do you defrost scallops?

To defrost, lay them in a single layer on a plate covered with a paper towel. Do not crowd them. Cover with plastic film and defrost slowly for 24 hours in the fridge.

What is the best way to cook scallops?

The secret to cooking the perfect scallop is to never overcook them – cook them quickly and carefully and you will always get great results. Scallops have many other uses than just the popular seared scallop. They lend a great savoury flavour and texture to chowder, where small pieces of chopped scallop make a chewy foil to the creamy veg. They can take the form of comfort food when either battered or crumbed or, for something more refined, sashimi scallops provide a fantastic option, especially when served with yuzu-infused soy sauce and micro herbs.

Greenshell mussels (Perna canaliculus)

What are greenshell mussels?

The ancient and incredible species of New Zealand greenshell mussels (or in Maori, ‘Kutai’) has been a valued human food source for over 800 years and has become globally recognised for its unique qualities. Forming an ancient and vital part of the ocean’s food web, greenshell mussels filter 360 litres of water a day – assisting in improving water quality and promoting healthy fish stocks. It’s through filtering water which these creatures get all their nutrients and sees them reach maturity in 12-24 months. Mussels are seeded on lines in an organic stocking, which breaks down naturally as the mussels attach to the lines. When mussels grow to around 100mm in length and are in plump condition, they are harvested off the lines and sent for processing and shipping. They are farmed solely in New Zealand and exported globally to over 70 countries, with around 5% coming to Australia.

How do you cook greenshell mussels?

Try coating them with garlic butter and breadcrumbs and toasting under the grill – or you can make them into a creamy New England style chowder soup with some crusty bread to mop up the lovely juices. Alternatively, try them in a Thai green curry with some coconut cream, fish sauce and kaffir lime leaves.

Pacific oysters (Magallana gigas)

Where do Pacific oysters grow?

New Zealand’s cool, clear waters are great for growing Pacific oysters. Introduced from Japan, they have naturalised to the coast of the North Island and the north of the South Island. Immature oysters, or spat, are caught on sticks and grown out on trays or in baskets. They are submerged just below the surface, where they filter feed just like mussels. They are exposed at low tide, which makes the oysters close their shell and strengthens the adductor muscle, the meaty bit inside the oyster.

When are Pacific oysters harvested?

After 12 months or so, the oysters reach a good size and perfect condition. They are harvested, cleaned, sorted and then very carefully shucked and snap frozen in the half shell.

Does Bidfood sell a wide range of oysters?

Bidfood does carry a wide range of oysters in our wholesale seafood range. You can learn more about our approach to Seafood at anytime via our website or by talking to a local branch.

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