Pouched Lamprey Identification Guide

Key identification features

• Large lamprey reaching 55-60+ cm, among the biggest Southern Hemisphere species
• Breeding males develop a striking balloon-like pouch beneath the throat, unique among lampreys
• Eyes set well back from the snout tip, unlike some smaller relatives
• Broad oral sucker disc lined with well-developed, radiating rows of horny teeth
• Silvery-blue body at sea, shifting to duller brown tones once in fresh water
• Two dorsal fins along the rear body, with no paired fins anywhere

Common look-alikes

• The short-headed lamprey is smaller, lacks the throat pouch entirely, and keeps a more forward eye position.
• The Australian lamprey is far smaller, never develops a pouch, and stops feeding as an adult.
• Sea lamprey from the Northern Hemisphere is a similar size but shows blotchy marbled coloration and never grows a throat pouch.

Where you'll see one

Pouched Lampreys are anadromous, spending a parasitic phase feeding on fish in the open ocean before migrating up coastal rivers of southern Australia, Tasmania, New Zealand, and southern South America to spawn, where the males' pouch becomes most obvious.