The Big Seaweed Search returns for summer 2025
The Marine Conservation Society and Natural History Museum’s Big Seaweed Search Week returns from 26th July – 3rd August 2025. The two organisations are once again calling on people across the UK to head to the coast and take part in the Big Seaweed Search – a nationwide citizen science project that’s fun, free and perfect for the whole family.
Scientists from the Marine Conservation Society and the Natural History Museum are keen to learn more about where different types of seaweed grow across the UK, and how their distributions may be changing over time. By taking part in the Big Seaweed Search, you’ll be helping to gather vital evidence that can be used to map and document any changes to our coastal environments.
Anna Bunney, Citizen Science Programme Developer, at the Marine Conservation Society, said, “Seaweed plays a really important role in keeping our ocean healthy. There’s still a lot we don’t know, and that’s where the Big Seaweed Search comes in. The more people join in, the better we can understand what’s happening beneath the waves and how to safeguard our seas for future generations.
“The great thing is, anyone can take part – you don’t need to be an expert or live near the coast. Just one trip to the beach is enough to help out. It’s a brilliant, easy activity for families or friends to enjoy together, while also supporting vital research.”
While there are over 650 seaweed species around the UK, Big Seaweed Search Week focuses on just 14 of the most commonly found. This helps the Marine Conservation Society and Natural History Museum map the distribution of particular seaweeds and gather long-term data. This, in turn, helps measure environmental changes and the potential impact on marine life.
The Big Seaweed Search monitors species like kelp, which are sensitive to rising sea temperatures, non-native species and ocean acidification. Globally, kelp forests are thought to be in decline, reducing the ocean’s ability to capture carbon and combat the climate crisis.
The data collected by volunteers helps scientists build a clearer picture of how our coastlines are changing and informs decisions about how best to protect them.
Dr Juliet Brodie, at Natural History Museum said, “The Big Seaweed Search is already shaping important scientific research. Data gathered has contributed to the UK Red List, helping to highlight seaweed species that are vulnerable or under threat. This information plays a vital role in guiding conservation efforts to protect these essential marine species and ensure the health of our ocean for years to come. It’s also inspired similar projects in places like South Georgia and Mexico. Working alongside passionate community scientists who share our commitment to a healthy ocean is truly empowering.”
Taking part in Big Seaweed Search Week is simple and open to everyone. There are training videos and downloadable resources available, including an identification guide to help spot the 14 species and instructions on how to take part.
Surveys can be done alone or in a group, and results can be submitted using a mobile, tablet or computer.
To get involved simply:
- Register to take part and download your guide and recording form at Big Seaweed Search | Natural History Museum
- Choose your 5m stretch of coastline to survey
- Fill in your survey form
- Take LOTS of clear, close-up photographs for your survey to be accepted
- Submit your survey through Big Seaweed Search | Natural History Museum
You can visit the Marine Conservation Society’s website for all the information you’ll need to get started.
Header Image: Billy Barraclough
