The Department of Conservation has conceded it does not have enough resources to properly monitor New Zealand’s endangered dolphins.

It comes after another dolphin was recently added to the agency’s death toll after being entangled in a commercial fishing trawl off the Timaru coast this month.

Since August 2023, 11 dolphins have died, most in set nets or trawlers.

The Department of Conservation’s (DOC) marine technical advisor Kristina Hillock said it’s estimated there are 15,000 Hector’s and 54 Maui dolphins, nationally.

“Maui dolphins, they are on the brink of extinction. There’s some indication perhaps that the population is stable but any impact at this point is not going to be good for them.

“Hector’s dolphins, on the other hand, are classified as vulnerable under our threat classification system. So they are doing a lot better but we still need to actively manage them, otherwise, they will go the way of the Maui dolphin,” Hillock said.

Marine researcher Elisabeth Slooten believes DOC is overestimating the dolphin populations and that it needs to do more regular monitoring.

The Hector’s along the South Island’s east coast were last surveyed 10 years ago, and the Maui dolphin gets checked on every five years.

Slooten said the approach would not be accepted in the US.

“You would need to have more frequent population surveys so that when you know how many dolphins are being killed, you know out of a population how big.”

Hillock said the information that has been collected on Maui gives DOC an indication of whether the population is stable.

“That will give us the kind of feel for recruitment into the population, like the deaths in that type of situation. In terms of Hector’s dolphins, we just haven’t had the resources to go into that detail.”

Half of New Zealand’s commercial fishing fleet now has onboard cameras to help monitor what is being hauled in, including any endangered species.

DOC will monitor the information collected before deciding what it will do next to protect the Hector’s and Maui from being caught.

“Ideally we would have 100% camera view but that’s not possible with government resources,” Hillock said.

“What they have done is prioritise the most at-risk areas, and most at-risk species, so, for example, the Maui dolphin habitat, that review is 100%, and it’s very high in some areas where Hector’s Dolphins are such as around Otago, and around the bottom of the South Island.

“It’s super important for people to be aware of these dolphins and to report any sightings to DOC… because those dolphins can be taken off to Massey University to be examined, and see how the dolphins died which again comes back to that evidence-based management which we need to protect these dolphins.”