This is a great video I discovered via bb. Craig Evans from forages along the beaches in Pembrokeshire and he has a whole youtube channel of him finding the freshest seafood then cooking it there and then.
He looks under large rocks and in pools, moving from spot to spot so as not to take from just one spot. He puts back anything that is too small and only grabs what he needs, which is really ethical and sustainable.
What he got that day: edible crabs, velvet swimming crabs, bearded rocklings, winkles and whelks. Cooked simply in water, may be seawater? The water was then flavoured with seaweed he called dulse plus garlic and powdered lobster shells he probably made himself then used to make couscous. A great idea and so easy for outdoor cooking.
In this day and age, living purely on foraging isn’t possible unless in rural or almost uninhabited areas. It seems to be a nice hobby providing not too many people do it, and they all respect the need not to deplete the ecosystem.