Getting seaweed savvy with the Big Seaweed Search

By: Jules Agate
Date posted: 8 September 2017

Our South West Volunteer Manager Jules Agate has been seeing seaweeds in a new light with the Big Seaweed Search (BSS). Read on to find out all about her macro algae adventures!

Seaweed Searchers

Here in the South West of England we’ve really taken to the Big Seaweed Search - like blue-rayed limpets to kelp! The BSS is a partnership project for the Marine Conservation Society with the Natural History Museum (NHM). The aim of the BSS is to involve the public as a force of citizen scientists to help us to find out how the distribution of different types of seaweed, and its abundance, is changing in response to changes in the marine environment.

The three key changes occurring in our seas that seaweeds are likely to be responding to are:


Despite almost encircling our coastline, with a phenomenal 650+ species in the UK, we still lack data on exactly what seaweed is growing where. This is why we absolutely need citizens to help us ‘do’ the science. There’s just so much coastline and so much seaweed to record!

Seaweeds are important in their own right too. They create the structure and habitat that provides shelter and food for thousands of creatures like urchins, molluscs and fish. Seaweeds are crucial to commercial fisheries, are used in foods, cosmetics and medicines and play a vital role in protecting our coasts from wave action and storm damage.

We have amazing seaweed diversity in our SW seas at the warmer end of the UK temperature spectrum, from huge strapping kelps to delicate looking coral weeds. Also there is a lot of alien invasive species growing in some SW localities, particularly Japanese Wireweed (Sargassum muticum) and Wakame (Undaria pinnatifida).


The BSS uses just 14 species (or groups of species where species level identification is difficult). The 14 are all likely to respond to environmental change and can therefore indicate to us what is happening to our seas more generally. They are also relatively easy to identify.

I became a bit of an expert last summer at rapidly picking out the 14 BSS target types from amongst the piles of those washed up on my local beach. My record is 15 min to collect samples of 9 species! I use the (carefully washed) samples I collect in displays at public shows, events and training sessions to demonstrate what the BSS is all about, and how to do it.


The beauty of the BSS is that it is very straight-forward, entailing just a 5m wide walk from the high to low shore, identifying and ticking off any of the 14 target seaweeds that you see. You’re also asked to make a rough estimate of how much is there and record some features of the shore. It is so simple that it doesn’t feel like you are doing a very big and important scientific experiment, but that’s exactly what it is; one that anybody can join, on any chosen shore (as long as there is seaweed!).

In September 2016 we ran a training session in Cornwall, very kindly organised by Simon Hocking of the National Trust, West Cornwall and his team, and lead by Prof Juliet Brodie from the NHM. This brought together over 40 people and completed three 5m surveys in the gorgeous Mounts Bay Marine Conservation Zone.The next week, I ran my own session for the Polzeath Marine Conservation Group and some more National Trust staff.


We’ve now had more than 20 surveys uploaded in the South West and it is really taking off. It’s great to see people getting closely involved with our previously over-looked marine macro-algae (aka seaweeds!) and it definitely feels as if we’re starting to build a clearer picture of the seaweeds around our coasts – exciting!

If you’d like to get involved: Check out the Big Seaweed Search website where you can:

Don’t forget to Tweet your seaweed activities using #BigSeaweedSearch to @mcsuk @NHMLondon

Contact if you are interested in hosting your own group survey or training in the SW and for other regions.

Further reading: Recommended guide to Seaweeds of Britain and Ireland (2nd Edition) by Bunker, Brodie, Maggs and Bunker £19.50 from the MCS shop