For many years from at least 1966 to 2003 I noted the presence of numerous Beadlet Anemones, Actinia equina, on the caves and gullies in Fishcombe Cove, near Brixham, South Devon. On a visit this year I was shocked to find none and spent a long time searching on one of the lowest tides of the year. Is this species sensitive to wave action or pollution? I also noticed that the extensive beds of bootlace weed (Chorda filum) which used to be present at this location are also absent. Is this indicative of some environmental change or pollution? Brixham has recently seen the completion of a major extension to the fish quay which may have caused an increase in suspended solids at this site.
1) The sudden disappearance of a population in an ideal exposed intertidal habitat is unheard of, but the almost disappearance of a less suitable sheltered habitat has been recorded at Shoreham Harbour (Kingston Beach). This disappearance was almost certainly due to the continual dredging operations of the Port Authority using suction dredgers which caused excessive suspended silt in the water that is inimical to this (and most) species of sea anemone as it interferes with their feeding mechanism.
2) Ideal habitats of the Beadlet Anemone are exposed intertidal rock faces (and artificial rocky environments like groynes and pipelines) with large wave and tidal movement between Mean Low Water Level and Chart Datum. They will be found elsewhere on the shore and in shallow water. The largest specimens are to be found on intertidal mussel beds. They feed on dead organic matter (and live organisms) and are highly resistant to organic pollution and eutrophic conditions in the short term (they may survive an isolated pollution incident).
3) Although found in rockpools, this is not an ideal habitat for them. If Snakelocks Anemones are present in pools, Beadlet Anemones may be eliminated or reduced significantly by this competition.
4) Tolerant of a large range of temperatures from freezing point to 28°C and above. This is from captive studies. This does not mean that they can maintain a population in the wild at these extremes. Their distribution on the European coast is not known to me. I do not know if they regularly inhabit the Mediterranean Sea. I would expect this species to be transferred on boats and to be present in harbours worldwide and I would be very interested to hear of records outside of the British Isles coast. Even on the north Cornish coasts other species of sea anemone may inhabit the same niches, notably the Gem Anemone.
5) Predators like the Tompot Blenny and the Grey Sea Slug would just crop a few intertidal anemones and would not decimate their numbers.