This long, narrow estuary with its wide range of fresh to salty, shallow to deep, and sandy to muddy habitats supports an extremely diverse range of birds, fish, invertebrates and plant life.

Over 70 species of resident and migratory waterbirds use the estuary as a feeding and resting area.

Bar-tailed godwits/kuaka, knots and golden plovers migrate here each year from their arctic breeding grounds.

Wrybills/ngutu pare, oystercatchers/tōrea, pied stilts/poaka and royal spoonbills/kōtuku-ngutupapa over-winter from their South Island homes.