Tucked away beneath a Gwynedd promenade are a series of strange features that have left some people scratching their heads. Bolted to new steel pilings supporting a revamped seawall in Bangor, they come across as large concrete cookies with no discernible purpose.
Similar objects have appeared in the harbours at Caernarfon and, in north Anglesey Amwlch Port. Some people have imagined them as modern artworks or climbing supports, others simply have no clue what they’re for.
Bangor’s 12 textured discs were retrofitted in the wake of a £6m food defence scheme which, in 2024, saw Hirael promenade raised 1.3 metres. The revitalised waterfront also has a new slipway and flood gates, and improved walking and cycling paths.
It’s hoped the specially designed concrete panels will boost coastal biodiversity. The eco-engineered structures mimic natural rocky shores, providing cracks and crevices that allow seaweed, limpets and snails to thrive on otherwise smooth harbour walls.
Spearheaded by the North Wales Rivers Trust and the Menai Strait Partnership Forum (MSPF), the “Living Sea Walls” project aims to repair marine habitats where hard coastal defences have displaced local ecosystems.
They’ve been likened to insect houses sold in garden centres, but for small marine creatures. MSPF said: “They help boost biodiversity, soften coastal infrastructure, and support healthier intertidal zones where marine life can thrive.”
The habitat panels are placed specifically where public harbours meet tidal flows. In Caernarfon, they were fitted to the walls of Victoria Dock. Sign up for the North Wales Live newsletter sent twice daily to your inbox
Living seawall panels covering more than nine square metres on the harbour wall at Amlwch Port(Image: Anglesey Council)
In a separate project, a huge array of 34 panels provided by Natural Resources Wales was secured to the harbour walls at Amlwch Port. Two of these were untextured control panels” – to see if the others really were making a difference.
When the panels were fitted last year, by Anglesey Council, Cllr Nicola Roberts predicted they would have “numerous benefits”. She said: “The specially designed panels can help filter particles from the water, leading to improved water quality, and they also reduce wave energy, helping to mitigate coastal erosion.”
The 3D structures have different textures for different host communities: Rockpool panels for springtails and juvenile limpets; crevices to shelter marine snails; honeycomb panels for winkles and dog whelks; and swim-through panels for algae and brown seaweed.
Master’s students from Aberystwyth University have been monitoring Amlwch’s living seawall to see if it works. At Bangor, the city’s university students are involved along with local volunteers.
Over the past year or so, awareness of the curious structures has been boosted via living seawall projects at local schools.
Join the North Wales Live WhatsApp community group where you can get the latest stories delivered straight to your phone