Explore > Nature
In the water and in the mud
To really appreciate how many creatures live in an estuary, you need to embrace the mud! It is home to millions or maybe billions of living creatures – not just the most obvious crabs, worms and shellfish. Together they form an incredibly complex web of life.
The lower reaches of the harbour contain beds of mussels, cockles and pipi. When the harbour bed is exposed at low tide an array of wading birds, some migratory and some resident, appear on the mudflats for a feast. The mussel population has been significantly reduced and only two mussel beds remain. Starfish feeding on the mussels have been attributed as a significant factor to the mussel decline and trials to restore the mussel populations are underway. The intertidal zone is alive with mud carbs, whelks and small plants. There is a large seagrass bed, a vital part of the harbour’s ecology, opposite the Port Ōhope store but it’s sadly in decline.
Seagrass is vital to the harbour. It helps stabilise sandflats, promotes biodiversity by adding complex structure to the harbour bed and is an important habitat for young fish such as snapper. New Zealand has a single native species of seagrass, Zostera muelleri. Lots of the seagrass in the Ōhiwa Harbour has been lost.