I really, really hate sea lettuce. It does this (see above) to the beach after rough sea conditions, and (see below) it’s really, really annoying on a dive.
The only good thing about sea lettuce is that it provides camouflage for super klipfish, like this friendly one I met on a dive last year at Long Beach. Their green colour often perfectly matches the colour of the sea lettuce.
There seems to be a sudden growth spurt of sea lettuce around the middle of spring, and for a few months all our favourite False Bay shore entries are littered with it. It gets wrapped around your hoses, caught in your BCD, tickles your cheeks in a most creepy manner, and (most annoyingly) makes photography a frustrating challenge as it waves about everywhere!
Sea lettuce is eaten by sea hares and other sea slugs, as well as some marine mammals. It’s also extensively eaten by humans, in salads, soups and stir fries. I wish they’d eat more of it.
Sea lettuce seems to grow on anything and anywhere. We’ve seen a lot of it attached to kelp stipes, taking advantage of the extra height to get some sunlight from closer to the surface. The leaves are incredibly delicate – sometimes only a single cell thick. This doesn’t make me feel sorry for it, though.
If you need any more evidence that sea lettuce is bad news, read this BBC news article. It is believed to have been directly responsible for two deaths in France. I think it’s even more malevolent than seals are!
Sea lettuce is a frustration to divers, and some people find it genuinely scary. It can be quite a vertiginous experience to swim over a patch of sea lettuce that moves beneath you. I think Corne enjoys sea lettuce, however, but for reasons that the following photo make clear – it releases his inner child!
Here’s what happens when sea lettuce dies… All the brown marks on the sand in this picture are from dead sea lettuce that has decomposed and left its tasty organic stain all over the shallows. These marks will eventually disappear, but not before providing a lot of nutrients for the organisms in the vicinity. Now THAT is what sea lettuce is for!
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