WELLINGTON, Oct. 20 (Xinhua) -- Numbers of the world's smallest and rarest marine dolphin are edging up, the New Zealand government said Thursday.
A new estimate of the population of Maui dolphin, found only off the west coast of New Zealand's North Island, was encouraging for the future of the species, Conservation Minister Maggie Barry said in a statement.
The preliminary results of a comprehensive scientific survey carried out over the last two summers estimated the population of the critically endangered dolphin at approximately 63 adults, with 95-percent confidence there were between 57 and 75.
This represented an increase from a 2010-2011 survey that estimated the number of adults at 55, with 95-percent confidence there were between 48 and 69.
"These results are encouraging, but there is no dispute the Maui population remains at a very low level and the government remains committed to ensuring their long-term survival," Barry said.
"What it does show is that Maui numbers over the past five years have stabilized, which can only be good news."
The survey, carried out by government and university researchers from New Zealand and the United States, used a boat-based "mark-recapture" technique taking genetic samples from encountered dolphins over two summers, then comparing results to count how many unique dolphins were spotted.
Another recent survey showed the population of Hector's dolphin, a close relative of the Maui dolphin and also endemic to New Zealand, was about 15,000, more than double the previous estimate of 7,000.
Primary Industries Minister Nathan Guy said the new figures were an encouraging sign that restrictions on fishing are having an effect on the Maui dolphins.
"More than 1,700 square kilometres off the west coast of the North Island have been closed to trawl net fishing since 2003, and over 6,200 square kilometres closed to set netting," Guy said in the statement.
Environment campaigners welcomed the news, but called on the government to do more to protect the Maui dolphin.
"Maui dolphins are still on the edge of extinction and need to be protected across their range to ensure their survival," Alex Smith, senior campaigner for the World Wide Fund for Nature (WWF) said in a statement.
"The New Zealand government needs to take urgent action to protect Maui dolphins and support affected fishers to move to dolphin-friendly methods of fishing."
Less than half of their habitat was protected, and set netting and trawling were the biggest threats to their survival, he said.
