"But the actual legal boundary of the reserve goes around those green buoys."
Rangers patrolling the area regularly having to approach fishers' boats to point out the boundaries, Ms Jordan said.
"There might be some confusion because of where the DoC buoys are but local people should know by now. These reserves have been in place since 2006."
Ms Jordan said there has been a marked recovery of reef fish and other marine species since the reserve was founded, increasing the harbour's appeal for recreational diving and snorkelling.
"It's a great place to come and enjoy but there must no disturbance of the marine life," she said.
Penalties for catching fish in a marine reserve can include imprisonment, confiscation of catch, boat, car and fishing gear, or a fine of up to $250,000.
Whangarei Harbour Marine Reserve covers almost 237ha, or 2 per cent of the harbour.
The reserve was approved by DoC in late 2004. Opposition, red tape and technical hitches delayed its opening until October 18, 2006. The reserve came about after 15 years of research and lobbying by students at Kamo High School. The original proposal included another 600ha around Limestone Island, but that was abandoned after running into opposition from anglers and iwi.
-Whangarei Harbour Marine Reserve comprises Motukaroro Reserve (26ha) and Waikaraka Reserve (210.5ha).
-Fishing is banned in the reserve, but snorkelling, diving and swimming are encouraged. It is identified by shoreline markers, buoys and signs.
-Experiencing Marine Reserves holds free guided snorkel days at Reotahi/Motukaroro in summer.
-Northland's other no-take marine reserve is the world-famous Poor Knights.