However, the Department of Conservation (Doc) says the work allows for a deeper understanding of the dolphins and is crucial to achieve a level of scientific rigor required to advocate for their appropriate management.
University of Otago emeritus professor of zoology Liz Slooten said the work now under way by Doc — collecting biopsies off the small Otago coastal population of Hector’s dolphins — wrongly suggested more research was necessary rather than providing the animals the protection they required.
Prof Slooten said instead of collecting tissue samples, genetic information could be gathered from water samples, using environmental DNA (eDNA) studies, which had advanced significantly in the last few years.
And the technique of "sticking a dart" into a living dolphin could make the animals "boat-shy", which would jeopardise studies where researchers took photographs of identifiable individuals to determine how far they ranged.
"Basically they're using outdated methods to answer a question that doesn't need answering," Prof Slooten said.
"The question they're hoping to answer is whether a dolphin that's caught in a fishing net or otherwise killed due to human impact — if dolphins were removed from the Otago population, would it be replaced by a dolphin from a neighbouring population?
"And to answer that question you need to spend lots of time out on the water photographing dolphins with distinctive markings and studying their movements."
Prof Slooten said Doc and the Ministry for Primary Industries (MPI) managed Hector’s dolphins as a nationwide population and were not paying attention to the fact that the distribution around the country was highly fragmented, and "they really need to have more localised management".
The coastal Otago population of Hector’s dolphins numbered about 45 animals, ranged about 50km, and did not interact with Hector’s dolphins from elsewhere, she said.
Two Otago Hector’s dolphins were caught as bycatch recently and "instead of saying this is what we're going to do about it, MPI asked the fishermen what are you going to do about it?"
"It would mean that instead of saying, ‘Oh dear, we're catching a lot of dolphins off the coast here, let's protect them’, you're saying, ‘Oh we need to do more research’ — and that's been going on for literally four decades now.
"The government agencies have known about this problem for a very long time and they just always seem to come up with reasons for not doing anything yet."
Doc senior science adviser Anton van Helden said while there had been advances in eDNA it was costly, time-consuming and "you wouldn't get the quality of data that you would get from biopsy sampling".
Mr van Helden said the amount of time dolphins were subject to interactions with humans was less using biopsy sampling and he had seen no evidence it made the animals boat-shy.
The basic technique had been used in New Zealand for 25 years, it was used internationally, and it caused very little harm to the animals, Mr van Helden said.
It would allow researchers to understand the relationships between individual dolphins within that area and it could be used for a range of other analyses, including determining the age or potentially reproductive status of an animal.
"You can't get that from eDNA."
Mr van Helden said recent eDNA work by Otago University researchers had shown Hector’s dolphins living on Otago’s coast could be genetically more related to animals further south and therefore less connected to other East Coast South Island populations "raising important questions about . . . what this means for their exposure to threats such as fishing activity".
"I would say that whilst the eDNA stuff has been instrumental in bringing up this issue about the management of this particular population, and I think that's great, it's not going to get us across the line in terms of being able to robustly demonstrate to government that this is something they need to take action on."
A Doc spokeswoman said yesterday biopsies would be collected until March 22 weather permitting.
