A Strawberry Anemone (Anemonia fragacea) glowing under UV light!
Many of the species living in the rock pools are nocturnal or crepuscular (active at dawn and dusk). They hide away in the day to protect themselves from predators like curlews, oystercatchers, turnstones and gulls.
However, when the sun sets and these predators return to their roosts, the usually shy and secretive creatures of the rock pools are free to come out in full force! Even animals that make their homes in deeper ocean waters will often come to the shore.
This gives us an amazing opportunity to find some truly spectacular wildlife that most will never see!
When we go out on our night rock pool safaris we bring with us ultra violet torches, not just for fun but to see some of the rock pools glowing inhabitants! Many species of anemone, crustaceans, fish, bivalves and mollusks have a green and sometimes pink glow to them under UV light. Hidden patterns and hard to see features are suddenly clear as day. But how and why do they glow?
Creatures that glow under UV light can generally see more colours than us. As humans we can only see wavelengths from 380 to 700 nanometers but many rock pool animals can see outside of this range allowing them to detect wavelengths that are unperceivable to us.
When we shine UV torches on wildlife their tissue absorbs the shorter-wavelengths of light, that are invisible to us, and re-emits it as a longer wavelengths that we can perceive. They use specialized microscopic structures in their tissue to achieve this.
Displaying these bright glowing patterns acts as a form of communication between individuals of the same species, as well as other species. Some animals such as anemones use their intense patterns as a warning to would be predators.
The tentacles of a Snakelocks Anemone (Anemonia viridis) glowing under UV light.