Preheat the oven to 180 degrees. Season the scaled and cleaned gilthead sea bream inside and out with salt. Place the seaweed on a wire rack or baking tray and place the gilthead on top. Cook in the oven for 12 minutes (place a pan under the grill).
Season the gilthead with pepper only after cooking.
Peel, core and dice the tomatoes. Juice of one lemon, olive oil, a little bit of salt and coriander seeds, pepper, basil, fresh coriander leaves, tarragon and parsley in a hand mixer form and mix well. Transfer to a suitable bowl and stir in the tomatoes.
Serve the sea bream with the sauce. It goes very well with small boiled peeled potatoes.