The Department of Conservation (DoC) has warned Northland boaties to stay clear of a mother dolphin carrying her deceased calf on her back in the Bay of Islands.

The calf is suspected to have been stillborn but the mother is "displaying strong maternal bond behaviour as typical with marine mammals", DoC says.

Dr Catherine Peters, Senior Ranger Biodiversity, says the mother is still grieving the loss of her child.

"This female needs everyone on the water to give her the extra space and respect her needs whilst she copes with her loss."

Dr Peters said people on the water need to take extra care, but "if in doubt avoid all dolphin groups in the Bay of Islands".

The rest of the mother's pod has, at times, left her as she frequently drops the calf and circles back to collect it again.

DoC has a list of guidelines for approaching Dolphins when in the water -

carefully approach dolphins from their side and slightly to the rear

operate your boat slowly and quietly at 'no wake' speed within 300m

don't approach a group of dolphins if three or more boats are already within 300m of the group

manoeuvre your boat carefully - do not obstruct their path, cut through a group, or separate mothers from calves

if you would like to observe bottlenose dolphins switch off your motor and give the animals plenty of space - this lets the dolphins carry on with important activities like nursing and catching fish. If they are not interested leave them alone

give dolphin mums and calves extra space

if you spot a dolphin less than half the size of an adult, keep your vessel 100m away from the mother and calf

give bottlenose dolphins a break from all boats between 11:30am and 1:30pm do not approach them during this time.

Newshub.