Phalacrocorax aristotelis is a medium sized member of the cormorant family, with a body length of up to about 78 cm and a wingspan up to 1.1 m. The body is elongated with a long neck and tail. The adult is all black, including legs and feet, with a conspicuous yellow gape, the bare patch of skin at the corner of the mouth. The strong, straight bill is yellowish in non-breeding season and black during courtship. During breeding season the plumage aquires a green gloss and a large tuft of elongated feathers forms a conspicuous crest in the centre of the crown. Juveniles are a dark brown above and pale brown below with a white chin. The European shag is similar in appearance to the cormorant (Phalacrocorax carbo) but smaller and more slight with a thinner bill.