Like here in Parenga Channel, these are nurseries for small fish and rich habitats for shellfish and other crustaceans.

Parengarenga is like a time machine, a vision of what many New Zealand harbours once looked like. Before Auckland’s suburban development flooded the Waitematā and Manukau Harbours with sediment, they too were carpeted in verdant seagrasses.

What happens on land flows to sea. Rural run-off, nutrient-loading from fertilisers, forestry slash, sediment from development, sewage overflows and urban run-off are among the most destructive threats to the marine environment. We need to clean up our act.