A lot of people ask me “How do I know if the sea water is clean and if it’s safe to gather seaweed, pick shellfish, fish or forage for sea vegetables?”
Don’t forage near town sewage and drainage outlets.
Avoid river outlets with a high amount of green algal bloom which is often an indicator of fertiliser run-off.
Look at the water. Murky, slimy water devoid of sealife is giving you clues. Whereas clear water full of pollutant-sensitive sea anemones (such the snakelocks anemone Anemonia viridis, the beadlet anemone Actinia equina, and the strawberry anemone A. fragacea) are a good indicator of water quality. They are sensitive to low oxygen and high chlorophyll a conditions. Anemones are also very sensitive to oil pollution and lose their ability to feed and reproduce. If there are chemical pollutants in the water, sea anemones start to whiten – losing their colour – and die off quickly. The richer the variety of sea creature and brown seaweed species on the shore the better. See this Defra report for a full list of rocky shore health indicators.
The government do, and require many commercial companies to do, coastal water testing, for various reasons. These can be helpful for learning more about the water quality near your beach or section of the coast.
FSA monthly reports on monitoring for shellfish in Scotland: click here
SEPA monitoring of Scottish bathing waters: click here
For England and Wales use Safer Seas Service alerts from Surfers Against Sewage: click here
UK government bathing water test results for England: click here