Can you remember the magic feeling when you first, oh-so-nervously, touched the tentacles of a sea anemone? Your surprise at the instant retraction, and then your patience in waiting so you could do it again.
Crouching by the rock pool, daring those beautiful tentacles to re-emerge, teasing other children around you who wouldn’t, even ever-so-gently, touch the swaying marvels. How can a computer game compete with, let alone beat, that?
For many Australian children lucky enough to live by the coast, or spend holidays there, sea anemones were, and still are, an introduction to the wonders of our marine environment. They are found throughout the world (over 1000 species), with sizes ranging from a tiny 1.25cm to up to 1.8m across. Colours vary as well, and the largest and most varied sea anemones tend to occur in tropical waters. Although pretty, sea anemones are carnivorous predators – waiting to entrap passing fish, snails, crabs or zooplankton within their venom-filled tentacles.
These tentacles have poisonous stinging cells called nematocysts. The tentacles surround a central mouth, ensnare and paralyse the prey by shooting out a filament that injects a neurotoxin into the hapless prey, guide the stunned prey into the mouth and digest it within the sea anemone’s tubular body (the waste is excreted back through the mouth).
Some divers have been stung by sea anemones’ tentacles; generally, the venom isn’t strong enough to cause harm to humans. Of course, each person is different, so be sensible when dealing with any venomous creature.
Usually sessile, sea anemones can however creep around on their suction foot, or even detach themselves and swim off. Mostly they attach themselves to rocks, reefs or other structures, but some can burrow into the sand whilst others, like the brain anemone, are pelagic – they live in the open sea (below, with tentacles retracted).
Sea anemones tend to cover their bets when it comes to reproduction. Asexually, they divide by budding or splitting in two – each half forming a new sea anemone clone. Some species are hermaphroditic (having both female and male reproductive organs), whilst others have separate sexes. In these cases, the fertilised eggs become larvae and develop into sea anemones. Apparently, sea anemones have the potential to live forever, as they do not age (but their predators don’t seem to know that).
As ever, these marine treasures are too precious to lose. They need us all to value, protect and cherish them so that everyone in the future can experience the magic of sea anemones.