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Seafood guide3 min readUpdated 26 May 2026

By the Down The Cove editorial team

Buying Shellfish

well comes down largely to one word: alive. Crab and lobster should be lively, mussels and oysters tightly shut, and scallops plump and sweet-smelling. Here is how to buy the freshest shellfish — from the fishmonger, the supermarket or straight off a Cornish boat — and how to choose sustainably so there is plenty for next year.

Read the guide
Fresh live crab, lobster and mussels on ice at a Cornish fishmonger's counter
Buying, storing & preparing seafood

Seafood guide

Seafood notes

A simple route through buying, storing, cooking and serving seafood at home without making the page feel busy.

Buying Shellfish is here to make seafood feel easier at home: what to buy, how to handle it, and how to cook it with confidence.

Choose wellWhat to look for before it reaches the kitchen.

Start with seafood that looks and smells fresh, then keep the plan simple. Good fish, shellfish and coastal ingredients do not need a complicated route to the plate.

Keep it freshStorage, freshness and calm food handling.

Keep seafood chilled, unpack it when you get home, and cook it while it is at its best. A calm kitchen starts with good storage.

Cook simplySimple heat, short timings and clean flavours.

Use gentle heat, short timings and a little patience. Most seafood rewards simple cooking more than heavy sauces or overworked methods.

Serve with confidenceFinishing touches that keep seafood inviting.

Serve seafood with clean flavours, enough time to rest, and a little confidence. Lemon, herbs, butter, good bread or a simple salad often do the job beautifully.

The full guide

Read straight through, or use the seafood notes above to keep buying, cooking and serving simple.

Shellfish Buying Guide

If you are buying shellfish to cook yourself then make sure that it is alive. When a lobster or crab dies bacteria will quickly destroy the meat.

Even if you are buying shellfish that has already been cooked, it is still important to make sure that it is fresh. See below for our guide to ensure this.

Local Fishmonger

The local fishmonger will usually have fresh shellfish for sale but, if you want a crab or a lobster it may well be necessary to order with them in advance. Local fishmongers source the majority of their shellfish directly from their local markets and fishermen. Fishmongers are also very knowledgeable about the products they sell and will be able to give recommendations.

Supermarket

Supermarket fish counters will normally have live mussels but it is unlikely that they will have live crab or lobster. If they have it on their fish counters it will normally be cooked. If you are looking for a lobster in a supermarket you will usually find a whole frozen lobster in the freezer cabinets but these will invariably have been imported.

Prawns bought in supermarkets will almost always have been frozen first. It is important to be aware of this as, in some cases, you will not be able to refreeze them.

Down the Cove

If you go down to the cove and meet the fishing boats coming in you can usually buy a lobster or crab directly from the fisherman. It will, of course, be very much alive but just follow the instructions on our pages and you will end up with a delicious dinner!

Mussel and Oyster Farms

Mussels and oysters are farmed in the UK and, in some cases, it is possible to buy directly from the farms. Both mussels and oysters are farmed in Cornwall and the ones we know of are in the River Fal, the Helford River and the Fowey Estuary. We have provided links to the farms on our links page.

Our recommendation is to always buy live shellfish directly from the people catching it or farming it as you can then guarantee its freshness.

Shellfish Sustainability

The sustainability of different shellfish is closely being monitored by Cornwall Sea Fisheries, however the rules for inshore and offshore fishing can be different. As our website is about local coves we will tell you about the current rules governing inshore fishermen. Our preference will always be to source your shellfish from local inshore boats or farms.

Lobster

Female lobsters that have eggs (called 'berried' lobsters) are not allowed to be landed. If a fisherman catches a 'berried' lobster then they must notch the tail with a 'V'.

It is also not allowed for a fisherman to land a 'V' notched lobster (with or without eggs), so the lobster will be returned to the sea until it has shed its shell.

Crab

The sizes of crab allowed to be landed are closely monitored.

It is not possible for a fisherman to land a crab that is under-sized ensuring sustainability.

Prawn

Most prawns for sale in supermarkets in the UK are imported from the East and the North Atlantic. Those offered for sale are normally farmed and therefore from a sustainable source.

Mussel

Most mussels offered for sale in the UK are farmed and therefore from a sustainable source.

Oyster

Like mussels, most oysters offered for sale in the UK are farmed and therefore from a sustainable source.

Scallop

To ensure the sustainability of scallops, a preference should always be given to sourcing scallops that have been hand picked by divers. They will be more expensive but should still be the first choice.

How to Check your Shellfish is Fresh

Lobster and Crab

You should make sure that their eyes are bright and clear. Lobsters and crab should be alive when you buy them - never buy a dead uncooked lobster as you don't know how long it has been dead and bacteria spread rapidly in dead crustaceans. They should be lively and move their legs and claws when handled. A limp lobster or crab is close to death.

A live fresh lobster or crab should feel heavy to handle and seem heavier than it looks.

Mussels and Oysters

Mussels and oysters should be alive when you buy them. Live mussels and oysters will have tightly closed shells. Shells that are open should be discarded.

Scallops

If buying scallops in their shells, make sure they are alive by checking that the shell is tightly closed. If buying scallops that have been shucked (opened) they should look nice and plump and moist.

Prawns

Prawns are usually pre-frozen. Go for prawns from cold waters like the Atlantic rather than warm water prawns from Asia as they have far more flavour.

Buying Frozen Shellfish

Most prawns available in the UK have been frozen and it will not be possible to refreeze some of these so make sure you check on the packaging to see if this is the case.

A Guide on Quantities of Shellfish needed

You should allow half a 1kg lobster per person.

One large crab will serve two people for a main course such as linguine or will provide enough meat to make four sandwiches.

When buying mussels bear in mind that it is likely that a few of them will need to be discarded during the cleaning process.

Common questions

Should shellfish be alive when you buy it?
For raw crab, lobster, mussels, oysters and scallops, yes — bacteria spread quickly once shellfish dies. They should be lively, or have tightly closed shells, when you buy them.
How do you check a crab or lobster is fresh?
It should be lively, moving its legs and claws when handled, with bright clear eyes, and feel heavy for its size. A limp crab or lobster is close to death and should be cooked at once.
How do you know if mussels and oysters are fresh?
Look for tightly closed shells, or shells that snap shut when you tap them. Discard any that stay open, as that means they are dead.
Is most UK shellfish sustainable?
Much of it is: mussels and oysters are mostly farmed, berried and V-notched lobsters must be returned, crab landing sizes are controlled, and choosing diver-caught scallops and local inshore boats all help.
How much shellfish should I buy per person?
Allow about half a 1kg lobster each. One large crab serves two as a main (or makes around four sandwiches). With mussels, buy a little extra as a few are always discarded during cleaning.

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