I often get asked if there are any poisonous seaweed around Britain. From my own research I discovered that Desmarestia is the only poisonous seaweed that you should leave well alone. However I wanted to double check my own knowledge against that of a world class expert.
So I went and asked Professor Michael Guiry, Director of AlgaeBase and world authority on seaweed. Here’s his reply:
“As far as I know, there are no really poisonous seaweed in this part of the world. “Our” Desmarestia species (4 of them and as you said mostly in deep water) produce sulphuric acid and can have a cellular pH of 2.
Anything else you might want to eat is free of poisons in the conventional sense as far as I am aware. However, care should be exercised when collecting in areas with high coliform counts and other bacteria, particularly in estuaries.
I have seen some really disgusting places on the south coast of England and would be loath to eat anything collected from shores from Portsmouth east to Norfolk, and anything from the major estuaries. The same applies to Dublin Bay, Cork Harbour, Inner Galway Bay, and Belfast Lough.”
So there you have it, straight from the horses mouth so-to-speak.
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{ 5 comments… read them below or add one }
Would Blue Flag status be a reliable indicator of a beach where seaweed would be safe to eat?
Paul: Yes Blue Flag is good as well as The Good Beach Guide which is compiled by the Marine Conservation Society.
Glad to see that you mention the issue of pollution and describe such large areas where you would not gather. The issue of pollution is one that is not given wide enough consideration as brown seaweeds are particularly susceptible. They are used for measuring radiation doses in the sea and because of the gulf stream things like technetium 99 can travel long distances. Seaweed can be very nutritious and will be a very useful food in the future but only if people become more aware and active on marine pollution.
Hi
there’s been some discussion lately of the toxic dump site at Haulbowline island in Cork Harbour. I am interested to know if any toxic substances have been found in any of the seaweed in Cork Harbour.
Thanks
Una – Haven’t heard anything, but then I am in Devon not Ireland