Cornish Sucker
This week’s Species in Focus is the Cornish Sucker. This unique looking fish may be little but packs a powerful ability to latch on to rocky surfaces using its adapted pelvic fins.
Love exploring rock pools? Curious about the weird and wonderful creatures living along our coasts?
This May, join the Big Rock Pool Challenge: National BioBlitz — a week-long nationwide mission to discover, record, and protect marine life, with a special focus on invasive species that threaten our native shores. Utilising the iNaturalist app and a sense of adventure, you’ll help scientists track the spread of non-native species while earning your Rock Pool Discovery Score through our online hub. Whether you're spotting a beadlet anemone or catching sight of something rarer, every record counts.
Anyone can take part — no experience needed, just curiosity and a love of the coast. Together, we’ll shine a light on the hidden life of our rock pools and build a national picture of how our marine ecosystems are changing.
Since the 1960s, new non-native marine species have continued to arrive on UK shores, with over 20 invasive species now established — and growing concern about further introductions in the years ahead. Invasive, non-native species are animals and plants that didn’t originally evolve in UK waters but have arrived — often through shipping, aquaculture, or climate shifts — and are now spreading along our coasts. Some of these species can outcompete native wildlife, damage habitats, or disrupt entire marine ecosystems.
Many are small, easy to miss, and under-recorded — which is where you come in.
The National BioBlitz follows UK Invasive Species Week (12–18 May 2025) and is part of a national push to track and raise awareness of the impacts of non-native species. By recording what you find in your local rock pools, you’ll help scientists build a clearer picture of what’s changing, and where. Your records will support conservation, biosecurity, and marine management efforts across the UK.
Want to learn more?
Explore this fantastic Marine Non-Native Species ID Guide from our partners at the Marine Biological Association (MBA):
MBA Marine Non-Native Species Guide (PDF)
17th to 25th May 2025
The Big Rock Pool Challenge: National BioBlitz is happening all across the UK — and anyone can take part, wherever they are. All you need to do is head to your local rocky shore, explore the rock pools, and record what you find using the iNaturalist app. It’s a flexible, week-long event, so you can choose the day that works best for you — whether that’s a sunny afternoon, a perfect low tide, or a moment of calm in a busy week. Take part on your own or with friends and family — and help build a national picture of marine life on our coasts.
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Join the Big Rock Pool Challenge: National BioBlitz and help us create one of the most comprehensive snapshots of UK rocky shore biodiversity! It’s a fun way to make a real impact on our understanding of marine life.
1. Visit your local rock pool
After signing up, head to your nearest rocky shore any time between 17–25 May 2025. You don’t need any special equipment — just check the tides, bring your curiosity, and explore safely.
2. Record what you find on iNaturalist
Download the free iNaturalist app (for Android; for ios), snap photos of what you see, and upload them to the 'BRPC National BioBlitz 2025' project.
Don’t worry — you don’t need to know the species. The app and our community of experts will help with ID.
3. Earn your Rock Pool Discovery Score
Log in to our online hub to see your Discovery Score — based on the rarity of what you find. Double points for non-native species that help scientists track marine change!
Remember to share your amazing discoveries on social media! Use #BigRockPoolChallenge and tag us – we can’t wait to see all your awesome finds.
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 across and beyond the South West.
This initiative is delivered in partnership with The Rock Pool Project and the Marine Biological Association. Together, we’re empowering people and their communities to connect with nature, contribute to valuable biodiversity data, and support the health of our coastal ecosystems for future generations.
This week’s Species in Focus is the Cornish Sucker. This unique looking fish may be little but packs a powerful ability to latch on to rocky surfaces using its adapted pelvic fins.
The Rock Pool Project Team pick out their top Rock Pooling Books
The broad-clawed porcelain crab is a charismatic little rock poolers favourite. It is the most common species of porcelain crab found in the UK and can often be found clinging tightly to the underside of rocks below mid tide level.
