The Snakelock anemone is a common anemone species found around the Kerry and Irish coast.
It is mainly seen anchored in rock pools or to rocky promontories between the high and low tide marks, especially from the mid tide level downwards.
Sometimes large numbers of snakelock anemones are found clinging to the fronds of sea grass (Zostera marina) that occur just below low tide.
The common name of this species is particularly descriptive, as the long flowing green tentacles with their purple tips resemble nothing more than the snake hair of the gorgon of Greek mythology.
Snakelock anemones grow to be relatively large, reaching a size of up to 70mm (c. 3 inches) across the base. The column is smooth, with a row of inconspicuous warts on the edge of the upper rim.
Each animal sports up to 200 tentacles with a maximum span of 180mm (7 inches) — although most Irish specimens are smaller than this.
Snakelock anemones are capable of fully retracting their tentacles into the central column, but unlike their relative the beadlet anemone (Actinia equina) they rarely do so, even when Stranded by the receding tide it’s not uncommon to see these anemones left high and dry with tentacles hanging in a limp mass from the top of the column. Although they may look distressed they are perfectly healthy and will resume normal activity as soon as the tide returns.
Sea anemones belong to a group of animals called cnidarians which includes hydroids, Jellyfish sea anemones and corals. In common with other members of the group they Posses stinging cells called nematocysts that they use to disable their prey.
Snakelock anemones feed on small fish and invertebrates that they snare with their tentacles. Prey animals are quickly paralysed by the stinging cells and are passed along from tentacle to tentacle and drawn into the anemone’s mouth.
Sea Anemones don’t tend to move much — although they are capable of crawling slowly on their basal disc, and in extreme circumstances can inflate their bodies with seawater and release their grip allowing water current to move them to a new location. Once an anemones find a suitable spot it’s likely to stay where it is for an extended period.
Such a sedentary lifestyle makes meeting a mate an unlikely prospect so Snakelock anemones have developed a curious method of reproducing. The entire animal literarily splits in two, producing a fully functional clone of itself in the process. This process usually takes a number of hours and is characterised by periods of intense activity punctuated by rest periods.
It is the most widely documented method of reproduction in this species, although it’s thought that sexual reproduction may also occur through the release of sperm and eggs into the water column as well as feeding on other animals.
Snakelock anemones derive some benefit from their symbiotic relationship with algae called zooxantheglae in their body tissue. These algae can convert sunlight into food, and are necessary for the long-term survival of the anemone.
Because the algae thrive in bright sunlight snakelock anemones tend to be found in brightly lit clear pools where they will be exposed to the maximum amount of light.
Some people have reported painful stings from the snakelock anemone. Although the skin of the human hand is too tough to be affected, there is anecdotal evidence that the tentacles can sting more sensitive areas of skin. Some swimmers have reported painful stings and welts on the abdomen after swimming through beds of sea grass populated by snakelock anemones.