The Hauraki Gulf is a 1.4 million hectare marine park, with over fifty islands covering an area from the East Coast of Auckland to Great Barrier Island, both Coromandel coasts and the Firth of Thames.
It's gradual decline and ongoing pollution problems are the reason a long-time campaigner for the Gulf’s health has written a book looking at this unique place with a view to promoting its protection and conserving the vast area for future generations.
Raewyn Pert is a director for the thinktank Environmental Defence Society and she has been involved with landscape protection, coastal development and marine management throughout the country.
She's also part of the Hauraki Gulf Forum, which acts as the guardian of the gulf's environmental health.
Raewyn grew up on the shores of the Hauraki Gulf and believes we are taking it for granted, and do so at our peril.
She says two of the main causes of environmental decline in the gulf are sediment and dredging and trawling for fish.
The muddy plume after heavy rain is devastating for marine life as is the heavy gear which is dragged along the seabed by fishing boats, she says.
“It’s often hard for people who don’t dive, who don’t snorkel, don’t put their head under the water to really see what’s happening.
“You can see the surface of the water and it looks as if everything’s fine, but when you put your head under the water it’s a different picture.”
In the future Auckland’s growing population will put further pressure on the already stressed gulf.
She says run-off from the land will have to be captured on the land and there will likely have to be stronger controls on recreational fishing.
The Firth of Thames is particularly vulnerable.
“The Firth of Thames was entirely carpeted with mussel beds and they could pretty much cleanse the water in the Firth of Thames within a day.
“It had beautiful clear water, lots of mussel beds. We lost those through dredging …. and they’ve never recovered.”