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Great Seagrass 

Help us survey seagrass this summer!

Seagrass is an amazing underwater habitat which not only produces the oxygen that we breathe but protects coastlines, absorbs carbon and provides a home to many ocean species. Despite being so amazing, seagrass is under threat from the many pressures affecting the ocean.

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Unfortunately not much is known about seagrass, in fact scientists don’t even know where most of the seagrass in the UK is. Without this knowledge it is impossible to adequately protect or restore this vital habitat.


That’s why Seawilding and BSAC came together to develop the Great Seagrass Survey.


What can I do?

As seagrass lives in shallow water you can take part in the surveys by simply strolling on the beach or if you are qualified, SCUBA diving or snorkelling.

Full details of how to recognise seagrass, undertake the surveys, submit your data and importantly how to stay safe are explained below.


Spread the word and help us discover where the hidden seagrass is! Keep a look out on our socials where we will be sharing more news and updates.

Any questions? Check out our FAQs below.

Take part

How to take part

Whenever you visit the coast we would like you to help us locate and map the hidden seagrass beds.


1. Decide if you want to undertake your survey strolling on the shore or, if you can, scuba diving or snorkelling. You don’t have to limit yourself to just one. You may want to complete a dive survey of some underwater seagrass and then do a survey on the beach following your dive. Alternatively if you are arranging a club outing, some members could conduct a dive survey in the deeper waters, some snorkel in the shallows and some survey the beach.

2.  Decide where to do your survey. The survey location map provides a guide to some locations that you may want to survey. The sites in the map are divided into a number of categories:


  • Locations where seagrass is suspected to be but no one has recorded it yet

  • Locations where seagrass has previously been recorded but require mapping

  • Own choice - maybe somewhere where you know there is some seagrass or a place that you fancy checking out

3.  Check out the materials on how to survey seagrass (below). These will take you through how to identify seagrass, how to map a seagrass bed once you locate it as well as how to gather information about the seagrass.

4.  Plan your survey.  Make sure that you read and follow all of the safety tips first. Remember, you will be responsible for your own safety.

5. Get out on the water and survey. Don’t forget to share pictures of your survey and your seagrass. We will be sharing pictures on the BSAC and Seawilding social media platforms.  You can collect data in two ways:

  • You can visit a site and tell us if seagrass is present or not. If it is present then you can take and upload a photo. You can then up load your result and photo on the survey form. This provides useful information regarding where seagrass beds are located as well as equally helpful information on places where they aren’t

  • If you want to make the most of your surveying you can map the seagrass bed that you find. This provides more detail which is really helpful for scientists in understanding more about seagrass. How to map the seagrass bed is explained below

6.  Upload your results. We recommend uploading your results as soon as you can following your survey. It quickly becomes much harder to remember what you did or where you saved a file. Full instructions on how to upload your data are given in the survey instructions. Keep an eye on your inbox for updates on the results from the Great Seagrass Survey. When we validate the data collected it is possible that we may need to contact you to confirm details of your survey, for example if you have made a particularly exciting discovery. Once all of the data has been analysed, we will send you a summary of what was learnt from the Great Seagrass Survey.

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How to survey

If Diving..

How to survey and map seagrass beds

Follow the steps below if you'd like to go that little bit further and survey and map what you have discovered.  We've created this handy little guide for identifying seagrass of which there are two kinds in the UK - Zostera Marina and Zostera Noltei. Downloadable pdfs of all our resources are available at the bottom of this page.  Be sure to checkout the Survey Tips and Equipment Guide.

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Safety tips

Safety tips

General survey safety tips

  • The site you choose should be safe to access and dive in the conditions on the day. Be prepared to abandon a survey at your chosen site if the conditions are not right

  • Ensure that you park safely and legally and are not blocking any emergency access points

  • Access the shore by a public right of way if possible or ensure that you have the landowner’s permission to access

  • Don’t drop litter or damage property, leave the site as you found it

  • Seagrass is happy growing where it is, please don’t pick or pull any seagrass up

  • Your safety is more important than your survey - if in doubt, don’t go out. You can always do your survey another day

  • In an emergency at the coast or at sea dial 999 and ask for “Coastguard”. They will coordinate the necessary rescue assets (e.g. coastguard mud rescue or cliff rescue teams, lifeboat, helicopter, ambulance)



Dive and snorkel safety tips

The map of potential seagrass survey sites shows positions of known and suspected seagrass. It is not a map of approved or safe dive sites. A seagrass site being marked on the map is no guarantee that it is safe to dive.


It is up to you to choose a safe site to dive and to be prepared to abandon the dive or change locations if the conditions are not right. Nor does it indicate public parking or access. It is up to you and your group to park and access the site, legally, safely and responsibly.


  • You should be properly trained and equipped to conduct snorkel or scuba dives

  • Ideally conduct your dives as part of a properly managed group who can provide surface cover whilst you are diving and be able to respond appropriately in an emergency

  • Leave word ashore with a responsible person who can contact the emergency services if you are overdue.

  • Ensure that you dive within the limits of your abilities and qualifications

  • Be aware of task fixation.  Data gathering is not of prime importance.  Your safe return to the surface is

Shore survey specific tips


  • Make sure you check the tide times before you start your survey. Aim to start your survey around one hour before low tide

  • Keep an eye on the sea while you are surveying. The tide can come in more quickly than you realise

  • Do not conduct your survey where there is any chance that you may get cut off by the tide

  • Walk only on firm sand. Do not walk out on mud flats or areas of sand which your feet sink into. If in doubt - don’t go out

  • Don’t conduct a survey or cross any area that you wouldn’t feel happy being on for a normal visit to the beach

  • Take care on rocks which could be loose, steep or slippery

  • If you aren’t dressed and equipped for snorkelling or diving, don’t enter the water

  • Know exactly where you are so that a) you are able to record your survey position accurately but more importantly b) you can tell the Coastguard exactly where you are in case of emergency.  The what3words app is a one way you can provide an accurate location

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Downloadable Resources

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