Beadlet anemone

One of the most common sights at West Runton rockpools, Actinia equina dots the rocky shore with a variety of colours: reds, oranges, and greens. Some of the individuals have striped patterns on the column, and this diversity of colour has led some to consider that A. equina may in fact be a few different species.

This is the main anemone occupying the shore here, with the occasional appearance of the dahlia anemone, Urticina felina.

A. equina is recognisable by its smooth column, and 'blobby' appearance when out of water. A hardy species, this anemone can survive drying out by retracting its 190 or so tentacles, retaining water inside, and covering itself in mucus. When in the water, the tentacles may be extended for feeding (they eat pretty much anything, including terrestrial insects!) and a bright blue ring around the top of the column can be visible. These are the acrorhagi, comprised of stinging cells (nematocysts) and used for fighting other beadlet anemones.

A. equina are a territorial species and will defend their position if touched by another anemone's tentacles. The loser will either crawl away slowly (yes, they can crawl!) or fall off the rock and be carried away to another location by the currents.

How this species reproduces is still under investigation. One interesting idea is that A. equina asexually reproduces, budding internally and creating a brood of clones. What is known, is that these mini-anemones are kept safe inside the parent's body, until they are ejected out of the mouth (which is also the anus) and settle on nearby rocks.

Source 1: https://www.marlin.ac.uk/species/detail/1561
Source 2: https://www.theseashore.org.uk/theseashore/speciespages/Beadlet%20in%20pool.jpg.html
Source 3: https://www.discoverwildlife.com/animal-facts/insects-invertebrates/facts-about-beadlet-anemones/
Source 4: Wilding, C.S. et al (2020) https://doi.org/10.1016/j.margen.2020.100753