Acres of shellfish have died in the past month in a north Auckland estuary smothered by mud.
That's according to an environmental group that's urging the council to force developers to limit the amount of sediment they discharge from building sites.
The Long Bay-Okura Great Park Society says the sediment has led to mass death of cocklebeds in the past month.
"The death mortality area is very localised round the Okura Estuary and north of the Weiti development," the group's deputy convenor Peter Townsend says.
"The mullet no longer fly, the stingrays are few and far between," he said.
"The shellfish beds are decimated - soon, we believe the shore birds will follow as their food sources decline.".
The Long Bay-Okura Great Park Society says the sediment discharge from building sites is the biggest threat to wildlife in the marine reserve. »