In the summer of 2024, Oregon had its worst paralytic shellfish poisoning outbreak on record. One shellfish sample tested at 5,500 micrograms of toxin per 100 grams of tissue, the highest level ever measured in the state’s history. Dozens of people got sick. And the harvest areas involved weren’t the usual suspects. That’s the part that should get your attention.
What’s actually going on
Paralytic shellfish poisoning (PSP) comes from saxitoxin, a neurotoxin produced by certain harmful algae, most notably a genus called Alexandrium. When shellfish filter feed during a bloom, they concentrate the toxin in their tissue. Eat enough of it, and it can shut down your nervous system. This isn’t new science. What’s new is where and when it’s happening.
NOAA’s National Centers for Coastal Ocean Science has been tracking a pattern along the West Coast and up into Alaska: warmer water is changing where these blooms show up and how long they stick around. Reporting from Alaska Beacon in March 2026 described algal toxins turning up in parts of the food web where they hadn’t been documented before. NOAA has also funded new PSP sampling efforts in places like Kachemak Bay and southern Washington, areas that historically weren’t considered high risk zones.
Put simply, the toxin isn’t behaving differently. It’s the map that’s changing.
Why this matters right now
For decades, PSP risk in North America was treated as a somewhat predictable seasonal and geographic pattern. Certain regions tested constantly because they’d always had blooms. Others tested occasionally, or not much at all, because history said they didn’t need to.
That assumption is getting shakier every year. Warmer water, shifting currents, and longer bloom seasons mean the “safe” regions of yesterday aren’t a reliable guide to tomorrow. Oregon’s 2024 outbreak wasn’t a fluke event that came out of nowhere. It was a warning sign that the old risk map needs updating, and Alaska’s expanding toxin detections back that up.
This is exactly the kind of story that’s easy to miss if you’re only looking at your own harvest area’s history instead of the bigger regional trend. A region with a clean testing record for the last twenty years can still be next.
What producers, harvest managers, and labs should know
- Testing frequency shouldn’t be based purely on a region’s past record. If your area borders or sits within a broader zone that’s showing new bloom activity, that history is worth revisiting.
- Watch for expansion, not just intensity. The story isn’t only that PSP levels hit record highs in Oregon. It’s that toxins are appearing in species and locations that weren’t part of the traditional monitoring plan.
- Rapid, on site testing matters more in exactly these situations. When a bloom shows up somewhere unexpected, the lag time of sending samples to a distant lab can mean the difference between catching a problem early and catching it after people are already sick.
- Talk to your regional monitoring programs. NOAA and state health departments are actively expanding sampling in places like Kachemak Bay and southern Washington specifically because the old boundaries are being questioned. If your harvest area isn’t part of that conversation yet, it’s worth asking why.
- Don’t treat a quiet history as a guarantee. Twenty years of clean tests in a given bay says a lot about the past and very little about next season, especially as water temperatures keep climbing.
Closing thought
The old mental model was simple: some places have PSP problems, some places don’t, and you can mostly predict which is which. That model is breaking down in real time. Oregon’s 2024 outbreak and Alaska’s expanding detections aren’t isolated headlines, they’re data points in the same trend. The safest move for anyone in this industry isn’t to assume your zip code is exempt. It’s to treat the map as something that’s actively being redrawn, and to test accordingly.