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The invasive crab Hemigrapsus sanguineus. Scale in centimetres.
The UK’s coastal rock pools are teeming with extraordinary marine life, yet much of their biodiversity remains under-recorded and underappreciated. That’s where the Big Rock Pool Challenge: National BioBlitz comes in. On 17th May 2025, we’re inviting people across the country to explore their local shores, record marine species, and contribute valuable data to conservation efforts.
This event is part of the Big Rock Pool Challenge, a project designed to make marine biodiversity recording more accessible, competitive, and engaging. Every species found and logged using iNaturalist earns points, and participants can compete in friendly challenges, whether at an official BioBlitz Battle in Falmouth or Plymouth or at their own local rock pools.
Why a National BioBlitz?
Rocky shore species play a vital role in our coastal ecosystems, yet they are increasingly impacted by climate change, pollution, and invasive species. By collecting data on species distributions, we can build a clearer picture of how these ecosystems are changing.
The National BioBlitz is timed to coincide with UK Invasive Species Week, drawing attention to the threats posed by marine non-native species. Through widespread participation, we hope to track the presence and spread of species such as the Asian shore crab (Hemigrapsus sanguineus) and wireweed (Sargassum muticum), while also celebrating the incredible diversity of native marine life.
How to get involved?
Taking part is simple—on 17th May, grab your phone, head to your nearest rock pool, and start recording what you find using iNaturalist—make sure you join the ‘brpc-national-bioblitz-2025’ iNaturalist project. If you’re new to marine species identification, don’t worry—our online resources and expert-led training sessions in the lead-up to the event will help you get started.
For those near Falmouth or Plymouth, our regular BioBlitz Battle events will be running on the same day, providing a great opportunity to experience the challenge first-hand. These interactive events bring people together to compete in teams, earning rarity points for species recorded, while learning from expert marine biologists and conservationists.
Building a nationwide citizen science network
Beyond the excitement of the National BioBlitz, this event is a key part of our strategy to expand The Big Rock Pool Challenge across the UK. By October 2025, we aim to establish six new local hubs, led by trained volunteer leaders who will run monthly BioBlitz Battles in their local communities.
Join the Challenge!
Whether you’re a seasoned marine biologist or a curious first-time rock pooler, we’d love for you to be part of this event. Every record counts, every observation matters. Together, we can create one of the most comprehensive snapshots of UK rocky shore biodiversity—and have a lot of fun doing it.
To learn more, sign up for updates, and find out how to take part, visit The Rock Pool Project or follow us on Facebook, Instagram, or Linkedin.
The Big Rock Pool Challenge is proudly funded by The ScottishPower Foundation and The National Lottery Heritage Fund, whose generous support enables us to inspire communities and deliver lasting environmental impact. This initiative is delivered in partnership by The Rock Pool Project and the Marine Biological Association.