By Dave Hansford - Last November, a baby Maui’s dolphin washed up dead on Sunset Beach, just south of the Waikato river mouth. Just a fortnight later, two dead females – an adult and a youngster – stranded further north, at Kariotahi Beach. Their demise meant the loss of some three percent of the total population of the world’s most critically endangered marine dolphin.

Maui’s, or popoto, lives only in New Zealand. There are perhaps 110 left on earth, living in 11 small groups along the northwestern coast of the North Island between Dargaville and New Plymouth. And their future looks gloomy – population models reveal we can’t afford to lose a single one from human impacts for another six years. That’s a break we’re unlikely to give them.

Maui’s like to stay close to shore, particularly in summer, when they’ve been seen in the Kaipara and Manukau Harbours. Typically, the visibility in such turbid, tide-swept waters is poor, so the dolphins get around by using ultrasound, taking a picture of their surrounds with high frequency clicks and reading their reply.

But ultrasound, it seems, has trouble spotting a monofilament gill net. Monofilament – essentially the same green line you see on a fishing rod – first appeared in gill nets in the seventies, set close inshore and around harbour entrances for dogfish, flounder and mullet – directly in Maui’s path.

They died in droves.

Their cousin the Hector’s dolphin, found around South Island coasts, fared only a little better; in 1970 they numbered 26,000. Today, just over 7000 remain.

Kirsty Russell of Auckland University has studied Maui’s dolphins since 1997. Taking skin samples, she read them for “genetic markers” – each animal’s own DNA fingerprint. “It’s kind of like a paternity test,” she explains.

From the results came an echo of disaster. “There’s definitely been a genetic bottleneck; the population has suffered a massive decline at some stage and we’re assuming that’s due to the gill netting. We’ve lost a huge proportion of the population.”

That in turn raises concerns for the dolphins’ genetic richness; if it’s compromised, they may not be breeding to capacity or could more readily fall victim to pathogens such as the Brucella bacteria that recently turned up in a sampled Hector’s dolphin. Brucella can cause abortion and sterility, and further tests have shown that the dolphins are still carrying the waste we threw away decades ago – toxic levels of dioxins, PCBs, metals and even the long-outlawed DDT – in their blubber. Maui’s are our most polluted marine mammal.

Russell believes there are fewer than 100 survivors. They range very widely in winter, she says, and while a group might confine themselves loosely to an area one summer, they’ll turn up somewhere completely different the next. “Two summers ago we had a sighting off Waitara. They hadn’t been seen there for 15 years. They’re like gypsies.”

In late 2003, despite a legal challenge from The Northern Inshore Fisheries Company, the Ministry of Fisheries (MFish) enforced a set net ban along the North Island west coast from the bottom of Ninety-Mile Beach almost to New Plymouth. It also imposed a ban on trawling within one nautical mile of the coast, but environment groups say that’s not enough.

In 2004 a coalition of conservation groups put a formal challenge to the Government. They demanded that the Department of Conservation (DOC) and MFish complete a long-overdue recovery plan to save Maui’s and Hector’s dolphins. “We had no confidence in their science or their vision,” says WWF’s conservation director Chris Howe, “so we came up with our own.”

They gave the Government six months, but the deadline passed unanswered. Two years later, the plan still languishes as a draft in DOC in-trays. Shaun Cooper of DOC’s Marine Conservation Unit says the plan “is still in the planning phase. We’re working on a timeline for consultation with stakeholders.”

That glacial pace is unacceptable to Howe, who can’t understand why MFish and DOC “haven’t agreed or even consulted on simple management objectives for Maui’s and Hector’s dolphins. Surely, as an iconic species found only in New Zealand, the government could agree to aim for some level of recovery?

“Instead, there’s talk of more research needed, and even though DOC has a draft plan, it’s been witheld under the Official Information Act.”

Last summer, 19 more Hector’s dolphins were found dead – 11 of them from entanglement in fishing gear – prompting Fisheries Minister Jim Anderton and Conservation Minister Chris Carter to propose interim protection measures while DOC grapples with its management plan. But the move, now closed to consultation, came too late to save a further six Hector’s found dead since last September.

The measures could mean commercial set net bans from Te Waewae Bay near Invercargill and along parts of the Canterbury coast, or at least a requirement for fishers to stay with their nets while set.

In the North Island, Russell says no Maui’s have drowned in nets since the ban was enforced, which may be why the interim plan stops at “discussions with [Port Waikato and Taranaki] set netters to assess the extent to which their fishing might represent a threat to dolphins”.

But Otago University marine biologist Liz Slooten has studied Maui’s and Hector’s dolphins for more than two decades, and says the absence of scars doesn’t exonerate set nets. She suspects too, that many more deaths go unreported. “We could stop gill net drownings tomorrow, she says. “It’s very readily preventable, simply by using other fishing methods. It’s not like we’re asking people not to fish here anymore – all we’re asking is that if you’re going to go fishing in an area where there are Hector’s dolphins, please don’t use gill nets. Surely that’s not too much to ask.

“We’ve dragged our feet for the last thirty years. How much longer are we going to have to wait? And will it be in time?”

Howe agrees; “Every day that goes by without decisive action … puts the species past the point of no return.”

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