Ships cause horrendous water polution and risk to sea habitats. Where do you think all their waste discharge and accidental discharge goes? And its not in small lots.
Was staying at a marae next to the water up there years ago & took one of the kids for a paddle and a local came running over & said don't go in the water there.
Too late, and both our lower legs ended up with an irritating rash for the next few days. Wasn't all due to ships but also all sorts of discharges from industry etc as well probably.
If it wasn't for iwi we'd be living in a poisonous puddle around the country.
Its long overdue that all industries, including farmers, managed their waste, treat it onsite, and don't discharge into waterways, the sea included, especially harbours.
As kids we spent our childhood in and around the rivers, lakes and beaches. There's a helluva lot more places now where you can't than then. A generation or two don't know what that is any more.
If you want to use a natural resource, take care of it!