Sea lettuce (Ulva lactuca) has an essentially pan-global distribution, is thoroughly palatable and very good for you. If you live near the sea you probably live near it and yet you probably haven’t eaten it. In Australia, it is not eaten now and the evidence is pretty strong that it was not eaten in any great amount by early settlers (despite a strong seaweed eating tradition in the UK and Ireland from whence settlers and convicts generally came) nor by Aboriginal people (for whom there is well-documented use of bull kelp (Durvillaea potatorum) in Tasmania but not much else).
There was a time nearly twenty years ago on an 11 day wilderness walk on New Zealand’s Stewart Island when on very light rations (due to a food packing glitch we discovered 2 days into the walk but pressed on through) that a lone Japanese tramper in the same back-country hut as us brought in seaweed that he had foraged to help us through. Lone Japanese outdoorsmen really do pop in the strangest places. It was sea lettuce, I recognized it, I knew it from home, and I hesitated because I simply didn’t yet know it as food. Only briefly though – I was really hungry (foraged mussels came to a more substantial rescue a couple of days later). I didn’t know at the time that the carbohydrates in seaweed are largely indigestible by people, and that I was mostly getting a huge serve of vitamins and minerals rather than much energy, but I was converted. I have nibbled at it when I see it on clean shorelines ever since. And more recently I have been making a fantastic dried condiment from it.
Because rock fishermen targeting blackfish (or ‘luderick’, Girella tricuspida) use it as bait, and perhaps because they will take it regardless of regulations, sea lettuce is specifically the only intertidal thing that may be collected in the Marine Reserve near my place. Out on the headland, there is a fairly consistent flow of seawater essentially like a river fed by surging waves on the higher side of the rock platform, and in it grows some of the best sea lettuce to be found anywhere. My son now expects to snack on it when we are out there on the miniaturized safaris of searching in rockpools, and I will always chew down a few ‘leaves’ whenever I am there fishing. And sometimes I will harvest a bowl full, to be dried and tucked away as a surprising delicious condiment.
Last autumn, going crazy on saffron milk cap (Lactarius deliciosus) harvesting, I bought a dehydrator. Just a cheap and probably inefficient one (a better option described here), but it has already earned its keep on dried mushrooms that we are still using 4 months later. It turns out that it does an equally grand job on sea lettuce. Previously I have oven-dried it, but I am now convinced that dehydrating is better.
Dried sea lettuce falls somewhere in between being a salad green, a condiment, a health food supplement or something as everyday as a sandwich filling (see here for the partner condiment of salted fish roe). You may be familiar with having a few strips in miso soup – although this is usually with wakame (Undaria pinnatifida), sea lettuce works very well too. It is easy, it is delicious in its mildness at best and inoffensive at worst, and as a result it is just plainly and simply odd that it is such a relatively unknown food. That said, it probably couldn’t bear too much popularity on city shores where heavy harvesting might make it suffer. So perhaps I should throw some active discouragement into the mix and warn you – there will be amphipods; like little alien spawn of fleas and prawns hopping about on your food, burrowing down away from the light and out of sight, somehow defying the capture of every last one before you might eat it. Or you could just see them as some extra protein, or very very very small lobsters perhaps.