The Big Seaweed Search returns for summer 2025

The Natural History Museum and Marine Conservation Society‘s Big Seaweed Search Week returns from 26 July - 3 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 everyone to get involved in.

Scientists from the Natural History Museum and the Marine Conservation Society 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 contributing valuable observations to a collaborative research effort that maps and documents changes to our coastal environments.

Professor Juliet Brodie, Research Leader, Natural History Museum said, “The Big Seaweed Search is already shaping important scientific research. Data gathered has contributed to the UK Red List, highlighting 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.”

While there are over 650 seaweed species around the UK, Big Seaweed Search Week focuses on just 14 that are good indicators of environmental change. Researchers at the Marine Conservation Society and Natural History Museum map the distribution of particular seaweeds and analyse these long-term data to monitor environmental changes and the potential impact on marine life.

The Big Seaweed Search monitors the impacts of 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.

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 contribute to this important research. It’s a brilliant, easy activity to enjoy with friends or as a group, while also advancing our shared understanding of the marine environment.”

The data collected by individuals and communities across the UK builds a clearer picture of how our coastlines are changing and informs decisions about how best to protect them.

The Museum is working in partnership with global cloud provider, Amazon Web Services (AWS), to enrich and accelerate their vital work. The data collected from the Big Seaweed Search will be fed into the Museum’s Data Ecosystem, a data platform built using AWS cloud technologies. The Data Ecosystem helps the Museum’s team of scientists to collect, enrich and share multiple biodiversity data types alongside environmental data such as water chemistry, rapidly and accurately, from a range of sources.

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:

1. Get your copy of the instruction booklet and recording form at Big Seaweed Search | Natural History Museum

2. Choose your 5m stretch of coastline to survey

3. Fill in your survey form

4. Take one clear, close-up photograph of each seaweed you record

5. Submit your survey through Big Seaweed Search | Natural History Museum

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Natural History Museum Press Office

Tel: +44 (0)20 7942 5654 / 07799690151

Email: press@nhm.ac.uk

About The Natural History Museum

The Natural History Museum is a world-leading scientific research centre and one of the world’s most visited museums. Our mission is to create advocates for the planet – people who act for nature.

Our 400 scientists are finding solutions to the planetary emergency - from reversing biodiversity loss to resourcing the green economy.

We are seeking an additional £150 million to transform our South Kensington building: placing our groundbreaking research at its heart, revitalising four existing galleries, opening two new magnificent galleries and delighting 1 million more visitors a year with the wonders of the natural world.

MCS Press Contact 

Evie Martin, Media Relations Manager (evie.martin@mcsuk.org / 07579 814217) 

Lauren O’Brien, PR & Events Officer (lauren.obrien@mcsuk.org)

Images

Please find a selection of high-res images here.

Notes to Editors 

The Marine Conservation Society is the UK’s leading ocean membership charity, working towards cleaner, better-protected, healthier seas. The charity highlights the importance of our ocean, and the life within it, through working with governments, communities, and industry to take action to restore and protect the marine environment.