Shellfish safety & the rules
Gathering your own shellfish is one of the great free pleasures of the coast - but clams, oysters and mussels filter huge volumes of water and concentrate whatever is in it, from bacteria to natural toxins. Get this part right and the rest is easy. Get it wrong and it can make you seriously ill. Here is what actually matters.
Only ever harvest from waters that are officially open and approved for shellfishing, and check the status on the day you go. No amount of rinsing, cooking or freezing makes shellfish from closed or polluted water safe. When in doubt, do not gather.
How to check before you go
Every coastal region runs a shellfish-safety programme. Before you set out, find your local source and check the exact area you plan to gather:
- Your state or country's shellfish-status map - most publish a live map of open, conditional and closed growing areas.
- The biotoxin / red-tide hotline or advisory page - updated when blooms open or close waters, often at short notice.
- The local fisheries or environmental agency - for licences, seasons, and size and bag limits.
The biotoxins - and why cooking doesn't fix them
"Red tide" is the everyday name for algal blooms that shellfish filter and store. The toxins are tasteless, odourless, and mostly heat-stable - so a clam that has taken them up is not made safe by cooking. This is exactly why open-water testing and closures exist.
Paralytic Shellfish Poisoning (PSP)
The most dangerous. Caused by 'red tide' algae, it attacks the nervous system - tingling lips, numbness, weakness, and in bad cases paralysis. Not destroyed by cooking or freezing.
Amnesic Shellfish Poisoning (ASP / domoic acid)
Causes stomach upset and, rarely, memory loss. It is why razor clams and Dungeness crab are tested and closed on the Pacific coast.
Diarrhetic Shellfish Poisoning (DSP)
Causes severe stomach illness within hours. Comes and goes with algal blooms, so open waters can close quickly.
Vibrio bacteria
Naturally in warm coastal water, concentrated by oysters. A real risk in raw oysters from warm months - cooking kills it, so when in doubt, cook.
Tingling or numbness of the lips, mouth or fingers, weakness, or trouble breathing after eating shellfish can be shellfish poisoning - seek medical help immediately and tell them what you ate. Do not wait.
Your pre-harvest checklist
Run through this every time, before you gather anything:
- The water is officially OPEN for shellfishingCheck your state or country's live shellfish-status map or biotoxin hotline for the exact area, on the day you go. Green on the map is the whole game.
- No red-tide or biotoxin advisory is in forceBlooms close waters fast. A beach that was fine last week can be closed today - always check the current advisory.
- You hold the right licence or permitMost areas require a recreational shellfishing licence, and some need a separate permit for lobster, crab or specific beaches.
- You know the size and bag limitsMinimum sizes, daily limits and possession limits protect the stock and are enforced. Carry a gauge and measure everything.
- You know the season and any protected speciesMany species have set seasons; some (queen conch, much abalone, egg-bearing females) are protected or closed entirely.
- You are away from pollution sourcesNever gather near storm drains, marinas, outfalls or after heavy rain, even in 'open' areas - runoff carries bacteria.
Handling your catch
- Keep it cold and alive. Live shellfish should stay cool and damp (not in fresh water or sealed airtight). Discard any bivalve that is already dead - a gaping shell that will not close when tapped.
- Purge the grit. Clams, cockles and mussels hold sand; rest them in clean seawater for a few hours to spit it out before cooking.
- Cook thoroughly when in doubt. Cooking kills bacteria (though not biotoxins). Steam bivalves until they open, and discard any that stay shut.
- Take only what you'll use. Stay within limits, leave the small ones and the reef to keep producing, and never strip an area bare.
Ready to get started? Pick a species from the shellfish guides, work out what suits you with the catch picker, and sort your kit with the gear guide.
⚠️ This is general safety guidance, not a substitute for your local shellfish authority. Rules, closures and toxin levels change constantly and vary by area - only your official regional shellfish-status source is authoritative. The responsibility to gather safely and legally is always yours.