Experts and activists say the Government's proposed response to recent Hector's dolphin deaths does not go far enough and more needs to be done to protect the nationally endangered species.
This comes after the Minister of Fisheries, Stuart Nash, directed Fisheries New Zealand to figure out a way to reduce the number of Hector's dolphin deaths.
A briefing to Nash from Fisheries, obtained by the Herald under the Official Information Act (OIA), shows the Government was concerned about the 12 reported Hector's dolphins caught in commercial fishing nets over the past two summers.
However, the briefing suggests the number is probably higher because of the likelihood that fishers are not reporting dolphins being caught by fishing vessels.
"Recent scientific work has estimated that approximately 42 Hector's dolphin mortalities are expected per year from set netting, and 4.4 mortalities from trawling."
A review of the Hector's and Maui Dolphin Threat Management Plan is underway but Fisheries is considering interim measures in the meantime.
These include developing vessel-specific threat management plans and the deployment of new-generation acoustic pingers.
The proposed measures also include: "Looking at fishing activity in relation to the Hector's dolphin distribution maps, which may result in additional commitments to avoid certain areas."
But Otago University marine scientist Professor Liz Slooten said these measures simply are not enough.
She said these are the sort of things the fishing industry has been talking about for a long time and there is "no evidence that any of those measures would be effective".
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"The industry and Government agencies have known about this problem for more than 40 years. The only way to solve this problem is for MPI [Ministry of Primary Industries] to extend the current protected areas, where gillnets and trawling are banned, much further offshore."
Greenpeace also said the measures don't go far enough.
"The measures suggested by the Minister of Fisheries fall critically short of protecting the world's rarest and smallest dolphins, and essentially resigns them to extinction," Greenpeace oceans campaigner Jessica Desmond said.
Greenpeace has called on the Government to put cameras on all commercial fishing vessels so regulations have to be obeyed, and all bycatch would be accurately reported.
The Government's plans to require fishing vessels to have cameras has been delayed several times.
The OIA also reveals that Fisheries considered if the use of emergency measures was warranted.
This would have meant the Minister of Fisheries would be legally allowed to place restrictions on fishing activities.
But officials decided against using this because the recent Hector's dolphin's deaths did not meet the threshold for emergency measures.
Conservation Minister Eugenie Sage said a discussion document on proposals to update the Threat Management Plan is expected to be released for public comment shortly.
"The plan review process has involved extensive independent research, risk assessment and evaluation and engagement with expert stakeholder forums."
But she said any measures the fishing industry wants to implement to reduce the risk of the dolphins' deaths are welcome.
"I and many New Zealanders want to see Hector's dolphin resilient and thriving throughout their range."
She said the revised Threat Management Plan is an important tool to do this.
According to the Department of Conservation, Hector's dolphins are classified as "nationally endangered".
There are an estimated 15,000 Hector's dolphins across South Island seas, with 9000 on the South Island East Coast where the recent captures have occurred.
Study uncovers new dolphin insights
Meanwhile, scientists have used sonar technology to reveal a critical link between Hector's dolphins and their surface fish prey around Banks Peninsula.
Making sure these dolphins have enough to eat is key to their survival, but monitoring the abundance of prey is patchy.
Using sonar technology, researchers led by Otago University's Dr Tom Brough were able to see how the number of fish rose in summer, attracting more dolphins and little blue penguins to the area and suggesting sonar can be used to investigate habitat use in these predators.
"The over-arching question that this work contributes to is essentially, why do dolphins hang out in certain areas and what makes these locations unique?" Brough explained.
"With this information, we can figure out what makes prime dolphin real estate, and ultimately protect the things that make good-quality habitat."
Brough's team spent thousands of hours on the water conducting hydro-acoustic predator-prey surveys.
These consisted of zig-zagging backwards and forward over areas they knew were key "hotspots" for the dolphins at the peninsula and areas of seemingly less desirable habitat.
The team's findings, just published in the journal PLOS One, suggested baitfish were important for good-quality dolphin and penguin habitats.
Further, it showed seasonal shifts in the availability of prey to these predators.
"Both these findings illuminate just how little we know about the important species in the middle of the food-chain," Brough said.
"That we don't know the basic information on the abundance, distribution and habitat use of these baitfish species is massive gap in our knowledge.
"If we could understand these aspects of baitfish ecology we would be better armed to predict and possibly adapt to changing ocean conditions we already know are occurring."