These are notes from early mornings on the rocky edges of the coast north and south of Barcelona, written to help me and anyone else read a sea with almost no tide, find what lives in its pools, and leave every stone the way it was.

I grew up on a coast where the sea went out half a kilometre twice a day and left pools the size of rooms. When I moved to Barcelona I assumed rock-pooling was over, because the Mediterranean barely moves. It took a spring of lockdown walks, once they were allowed, to see that the pools here are smaller, fewer and more easily missed, but they are full, and a calm morning after a few days of high pressure shows them off as well as any spring tide.

The notes cover two stretches that the coast train reaches in under an hour. North of the city the Maresme has coarse granite sand and low rocky points between the beaches. South of it the Garraf massif drops straight into the sea as pale limestone, with coves and ledges that catch drift after a storm. I go early, usually before eight, because the light is low, the water is flat and the beaches are still empty.

Nothing on this site is collected alive, and very little is collected at all. Photographs, sketches and notes come home; animals, shells with anyone living in them and stones from the pools stay where they are. Identifications are my own, checked against guides and reference photographs, and when I am unsure of a species I say so rather than guess in print.