mussel with algae over my hand

algae animals areas atlantic beach biology bivalve blackish blue dark das edible elongated environs european fauna foam format gastropod hand heterodonta interstitial invertebrate iodine joao lampa lampas life lisbon long low macro magoito marine molluscs mollusk mussel mytilidae nature ocean overcast pebble portugal rich rocky roundish saltwater sao season seawalled shore sintra species sublittoral summer teromphala tide waters waves