New Research Confirms Dolphins Are Disappearing
Newly published research from the Universityof Otagoconfirms that Hector’s dolphins are disappearing more than ten times
faster than populations can sustain.
Associate Professors Liz Slooten and Steve Dawson applied a standard method used to assess whether human induced
mortality is causing the decline of marine mammal populations to Hector’s and Maui’s dolphins. The technique was
developed by the US National Marine Fisheries Service and calculates the level of impact beyond which populations will
decline - the Potential Biological Removal (PBR).
Care for the Wild’s chief executive Dr Barbara Maas says, “The results of this newly published research closely match
similar models used by NIWA, the fishing industry and earlier analyses by the University of Otago and once again confirm
the utterly indefensible death toll fishing imposes on the world’s rarest dolphin species. It doesn’t take a biologist
to understand that killing Hector’s dolphins more than ten times faster than they can breed is unsustainable and will
lead to extinction. With a mere 111 Maui’s dolphins left in the world, there isn’t very far to go either.”
Hector’s and Maui’s dolphin numbers are severely depleted. Hector’s dolphins take years to reach maturity, breed very
slowly and only give birth to one calf. Populations are therefore extremely vulnerable. The death of even one animal a
year, whether as a result of fishing, pollution, marine mining, disease or boat strikes spells the end for most
populations. The figure for the species as a whole is less than ten animals a year.
“If Hector’s dolphins are to recover, fishing related mortality must be kept well below these limits”, says Dr Maas.
“But according to NIWA, each year 110 to 150 Hector’s dolphins die in commercial gill nets alone.” As a result,
Hector’s dolphin populations have dwindled by more than two thirds since the 1970s. Maui’s dolphins, the North
Islandsubspecies of Hector’s, are even worse off. More than 90% have already been lost as a result of net
entanglements.”
Full protection against human impacts, including commercial and recreational gill-netting and trawling would allow
dolphin numbers to recover to about 15,000 over the next 50 years.
“Every analysis to date has shown that if Hector’s dolphins are to be saved, gillnets need to be removed from their
habitat. Although the Government announced new fishing restrictions to improve Hector’s and Maui’s dolphin protection
against fishing earlier in the year, these measures don’t go far enough and won’t ensure population recovery.”
The scientific community, represented by the Society for Marine Mammology, the IUCN’s Cetacean Specialist Group and more
than 170 international conservation organisations have urged the Government to fully protect Hector’s and Maui’s
dolphins from fishing nets.
“Although the fishing industry played an active role in the research and public consultation that led to the compromise
measures agreed by the Government, it is now contesting the new regulations in court”, says Care for the Wild’s Dr Maas.
This wastes valuable time and resources and more dolphins will die as a result.
New Zealandholds this species in trust for the rest of the world. Unless New Zealandprotects Hector’s and Maui’s
dolphins will be lost to us forever.
ENDS