26 March 2012
New Research points the way to saving Hector’s and Maui’s dolphins
New research proves the effectiveness of Marine Protected Areas as an effective conservation tool to protect marine
mammals against fisheries bycatch. Yet, the dolphin species that was studied to provide this landmark result continues
to decline due to lack of protection.
Scientists from New Zealand and Australia spent 21 years studying Hector’s dolphins off the east coast of New Zealand’s
South Island. The results, published in the British Ecological Society's Journal of Applied Ecology today, confirm that
removing the threat of gillnetting and trawling from coastal waters successfully improved the survival of endangered
Hector’s dolphins.
“This is excellent news because it proves that the removal of fishing nets from their habitat benefits threatened marine
mammals,” says Dr Barbara Maas, Head of Endangered Species Conservation with NABU International – Foundation for Nature. “However, it also shows that unless a Protected Area is large enough, this positive influence cannot compensate for
mortality caused by fishing. The net effect is continued decline.”
“The study population and Hector’s dolphins as a whole are still on course to extinction. Late last year, another study
showed that 23 Hector’s dolphins drown in commercial gillnets off the east coast of the South Island each year. The
sustainable limit for this area is about one dolphin a year,” explains Dr Maas. “Unless the size of the 1170 km2 Banks
Peninsula Marine Mammal Sanctuary is enlarged, it will be a case of ‘The operation was successful, but the patient is
dead.”
Dr Liz Slooten, who has studied Hector’s dolphins since the 1980s and co-authored the latest research says, “The take
home message is that size matters. Marine Protected Areas work, but they have to be large enough in order to be
effective.”
“As things stand, the odds are stacked heavily against Hector’s dolphins,” say Dr Maas. “The likelihood that they won’t
recover to even half their original numbers within the next 50 years is at best 80%. Yet without fishing, populations
could double to 15,000. It is even more disconcerting that these calculations refer only to commercial gillnetting.
Other harmful fishing methods such as trawling and recreational gillnetting, or pollution, boat strikes, and marine
mining are not included.”
“This study is yet another reminder that Hector’s dolphins, including the almost extinct North Island subspecies of
Maui’s dolphins, remain poorly protected. Less than two weeks ago, the government announced a revised population
abundance estimate for Maui’s dolphins of some 55 individuals - the result of 30 years of decline due to fishing. But
fishing continues across much of animals’ range.”
“NABU International reiterates its call for the protection of Hector’s and Maui’s dolphins against all gillnet and trawl
nets in coastal waters up to 100 metres deep. It is the only rational course of action in light of the overwhelming
scientific evidence and the exceptional urgency that confronts us here. Unless the government generates this level of
commitment, the last few dozen Maui’s dolphins and their South Island cousins are bound to become a further addition to
the long list of extinctions New Zealand has suffered in the past.”
ENDS