Pouched lamprey

Lore & Background

The pouched lamprey has a thin, eel-like body with two low dorsal fins on the back half and no jaws, only a sucker. Adults caught fresh from the sea have striking silver skin, which soon changes to brown in fresh water due to biliverdin deposition. Their eyes are relatively small and located on the side of the head. When fully mature, males develop a baggy pouch under their eyes, which may be used to massage and oxygenate eggs; there have also been suggestions that the pouch in northern hemisphere species has been used by males during breeding times for gathering stones to make a nest.

Reader's Guide

The pouched lamprey is significant as the only lamprey species in New Zealand and as a traditional Māori delicacy. Its life cycle includes a freshwater larval stage of about four years, a six-month metamorphosis, and a parasitic adult stage in the sea where it attaches to fish and rasps tissues. Adults return to fresh water, spending up to eighteen months maturing before spawning, and may live up to 105 days after spawning, wrapping around egg masses to provide parental care. The species faces threats from predation by albatrosses, shags, large fish, and marine mammals, and a hypothesized decline due to degradation of water quality in lowland waterways. Historically, Māori used methods such as disturbing lampreys at waterfalls and placing weirs across rivers with woven traps; European settlers also adopted them as food due to the history of lampreys as delicacies in Europe.

Did You Know?

• The pouched lamprey is the only lamprey species found in New Zealand.
• Males develop a baggy pouch under their eyes when fully mature, possibly used to massage and oxygenate eggs.
• Adults have been recorded living up to 105 days after spawning and provide parental care by wrapping around egg masses.
• Traditional Māori catching methods included using utu piharau, a weir across rivers leading to a woven trap, some over 15 m across.