Not all jellyfish is edible! Indeed some is extremely dangerous.
Rhopilema esculenta is, so far as I am aware, the only jellyfish you can eat. it is maybe significant that even Rick Stein has never appeared on television to show us how to prepare and eat this delicacy.
Still, here is a recipe I found on the www.
The tentacles are removed before the large round upper portion or canopy (as much as 30 cm (12 in) in diameter) is dried. It becomes translucent and yellow, like old parchment. It is usually sold in plastic packets, heavily salted, and needs to be soaked for some hours in several changes of cold water. It is also available already soaked andshredded.
Jellyfish is something to be savoured in small amounts so don't buy or prepare too much. Shred finely (or buy it ready shredded) and marinate in a mixture of rice wine or dry sherry, ginger juice,2 sliced spring onions (scallions) and lukewarm water to cover. Leave for 15 minutes, then drain. Jellyfish has no flavour to speak of, but the crunchy resilience is a perfect example of the importance Chinese gourmets place on texture ingredients. Because of its texture and appearance, it is jocularly referred to as 'rubber bands'.
Sliced into fine strips and dressed with a mixture of vinegar, light soy sauce and sesame oil, jellyfish is served as one of the appetisersin a cold assortment, or presented as a salad with shredded crisp vegetables. Make a dressing by mixing equal parts of oriental sesame oil and soy sauce, and half the amount of Chinese red vinegar and sugar. Serve cold.
Andrew
ps I am with Matthew on seafood. An hour's drive from where I live on the south bank of the Clyde is Loch Fyne and one of the world's best seafood restaurants. Also in Glasgow there is a ready supply of Sashimi and all manner of other seafood options. I love it.
That sounds bad. Well you have to look after yourself in that case. You also have the disadvantage of being a scientist and therefore knowing what is bad for you. I am in blissful ignorance!