Take part

Contribute to real scientific research from the Natural History Museum and the Marine Conservation Society by searching for 14 seaweed species at any UK seashore, you take part at any time of the year and as many times as you like. 

You will need

Big Seaweed Search guide and recording form, a pencil and a camera or smartphone. 

Step-by-step guide

1. Download and print the Big Seaweed Search guide PDF (3.3MB) and recording form PDF (69KB) or request a free copy by emailing your name and postal address to seaweeds@nhm.ac.uk. Read the guide, including the safety information before you start. 

2. Visit a seashore anywhere in the British Isles. All shores are important for the research, but you will find more seaweeds on shores with hard structures such as rocks, sea walls and piers, as many species anchor themselves to these. Ideally, start your survey an hour before low tide as this time is best for your safety and access to seaweeds.You can check tide times at www.tidetimes.co.uk

3. Select your survey area – a five-metre wide plot that runs from the top of the shore down to the sea. No need for a tape measure, five metres is approximately five adult paces. 

4. Starting at the bottom of the shore, take a photo of your plot (with your back to the sea). This provides the scientists with a bigger picture of the conditions on the shore when you carried out your survey. 

5. Walking away from the sea, thoroughly explore the whole of your five-metre-wide plot. Aim to cover the whole of your plot within an hour. When you find one of the 14 target seaweeds:

  • Tick it off on your recording form. 
  • Take a clear photo showing the identification features Don't forget to photograph each seaweed you record
  • Record its abundance as band-forming, patchy or sparse: 
    • Band-forming - the seaweed grows as an uninterrupted band right across the width of your five-metre plot.  
    • Patchy - the seaweed grows in large patches (greater than one metre across) but does not cover the whole width of your plot. 
    • Sparse - the seaweed grows in small patches (less than one metre across) 
  • If you later find a bigger patch, update the recording form. 
  • Only record living seaweeds, not dead ones washed up on the beach.

6. Now, the important bit! Enter your results and upload your photos using our online form, or post them with printed photos to: Big Seaweed Search, Angela Marmont Centre for UK Biodiversity, The Natural History Museum, Cromwell Road, London, SW7 5BD 

We’d love to hear what you got up to, so please share your stories with us on Twitter @NHM_London and @MCSUK #SeaweedSearch 

Staying safe on the seashore

  • Stay in a group, so you have help if something goes wrong. Take a mobile phone so you can make an emergency call if you need to.
  • Rocky shores have many trip hazards and can be slippery. Wear sturdy boots/shoes that provide ankle support and move across the rocks slowly and steadily.
  • Check the tide tables when you plan your trip and do the survey in the hour before low tide.
  • Don’t do the survey in bad weather. Stormy or windy weather can make the seashore dangerous, with large, powerful waves.
  • Dress appropriately. In winter, wear warm layers and a waterproof. In summer, wear loose clothing, a hat and sunscreen.
  • After touching seaweeds, always wash your hands before eating.
  • An example risk assessment is available for group surveys, but must be adapted for your needs before use: Example risk assessment (pdf 85KB)