Periwinkles (isam) substitutes

Small bivalves with firm, chewy flesh and a clean salty flavour.

Best for

edikang ikong, afang soup, fisherman soup, seafood okra

The best all-round match. Cockles are about the same size as a shelled periwinkle and have a similarly springy, resistant bite, so the soup still has those little chewy nuggets to find. They taste sweeter and less mineral than periwinkle, so the soup reads slightly gentler; a teaspoon of ground crayfish restores the depth. Add them in the final three to four minutes or they toughen.

Small hard-shell clams, shelled, or drained canned baby clams.

Best for

afang and edikang ikong, seafood pepper soup, okra soup

Widely available and genuinely good here: briny, sweet, and small enough to eat in one bite. They are softer and juicier than periwinkle rather than firmly chewy, and fresh ones release liquor that thins a thick soup a little, so shell them separately and add just the meat. Drain canned clams well, since the packing liquid tastes tinny in a palm oil soup.

Larger sea and land snails sold cooked in cans or jars.

Best for

matching the chew, afang soup, nkwobi-style dishes, fisherman soup

Texturally the truest swap, because these are actual snails: dense, firm and pleasantly rubbery in the same way. Cut them into periwinkle-sized pieces. Whelks are briny and mineral, close to the original; canned escargot is milder and often packed with butter and herbs, so rinse thoroughly or those flavours turn up uninvited in your soup.

Steamed or frozen cooked mussel meat, chopped to bite size.

Best for

everyday cooking, seafood soups, when nothing smaller is available

Easy to find and completely serviceable. Mussels are noticeably sweeter and much softer than periwinkles and they can shred if the pot simmers on, so stir them in off the heat or in the last two minutes. The soup gains a distinctly mussel-like sea aroma, which is pleasant but not neutral.

Cleaned squid rings or cooked octopus cut into small pieces.

Best for

texture-first substitution, afang, seafood okra soup

This is the swap to choose if the chew is what you miss. Squid gives an almost identical springy resistance, and octopus is even closer. Neither brings much brininess, so add a teaspoon of ground crayfish or a splash of fish sauce alongside. Squid needs either two minutes or forty - anything in between turns it into rubber bands.

Dried, ground West African crayfish or dried shrimp, already a staple in most of these soups.

Best for

restoring the sea flavour when no shellfish is available, budget cooking

This replaces the flavour and none of the texture, which is an honest trade rather than a compromise: most Nigerian cooks already have it in the cupboard and it is where much of the soup's savoury depth comes from anyway. The soup will taste right and simply have no chewy morsels in it.