Mordacia mordax

Description

Mordacia mordax, known as the short-headed lamprey, Australian lamprey or Murray lamprey, is a species of southern topeyed lamprey that lives in south-eastern Australia. It has a thin eel-like body up to 50 cm long, with two low dorsal fins on the back half. The skin is blue-gray or brown. Its eyes are small, and located on the top of its head. Adult Mordacia mordax live at sea and are parasites on other fish. They breed in fresh water, however, migrating up streams in southeastern Australia from Shoalhaven River, New South Wales to Gulf St Vincent, South Australia. The ammocoetes (lamprey larvae) remain in fresh water until metamorphosis, usually migrating to the sea around three to four years after hatching.