What are they?
Shellfish are molluscs such as oysters, clams, mussels and cockles, crustaceans like crabs, lobsters and shrimps and also echinoderms such as sea urchins.
Shellfish can cause severe allergic reactions in some people (anaphylaxis). In these severe cases, it is advised they carry an epi-pen (epinephrine auto-injector) at all times.
When to collect
As a rule, never collect molluscs after rainfall. This is because they are filter feeders so land run-off can contain all sorts of chemicals and toxins.
Shellfish are generally collected when there is an ‘r’ in the month, so from September to April. From May to August, shellfish tend to breed so they are best left to it. Oysters for example go very pappy when breeding so their flavour and texture is not good. Also, in the summer months, the sea warms up and there is the possibility of ‘red tide’ when algae blooms can occur. The algae produces a toxin called okadaic acid that can cause diarrhetic shellfish poisoning which can cause diarrhoea and vomiting for a few days.