While much has been done to protect the Hector’s dolphin, sadly, this endearing, unique gentle creature still hovers dangerously on the brink of extinction. Since the 1970s, the Hector’s dolphin population has plummeted by more than 70 per cent. Today, it’s estimated that there are between 10,000–15,000 Hector’s dolphins left. Māui, a subspecies found off the west coast of the North Island, is in a more perilous state with just 57 remaining.
The diminutive Hector’s dolphin is endemic to our coasts, beloved for its naturally inquisitive and friendly nature. Averaging just 1.2–1.5 m in length and weighing about 35–50 kg (males are smaller than females), Hector’s dolphins are recognisable by their distinctive grey and black markings and rounded dorsal fins.
No one has fought harder to protect the Hector’s dolphin than University of Otago zoologist and passionate dolphin advocate Professor Elisabeth Slooten. Originally from the Netherlands, a chance school holiday job at a marineland ignited Elisabeth’s lifelong passion for dolphins. In 1977, she immigrated to New Zealand, later gaining a Bachelor of Science and Master of Science in Marine Biology from the University of Auckland. She’s devoted her life to studying the Hector’s dolphin and is recognised as an expert worldwide.
It was while working on her PhD, together with her partner Steve Dawson, looking at the population, social organisation, and behaviour of Hector’s dolphins in the mid-1980s, that the pair unearthed some disturbing findings. An epic 8400 km circumnavigation of New Zealand showed Hector’s dolphin numbers were much less than previously thought and large numbers were being lost by drowning. On interviewing fishermen, they found some were catching a dozen Hector’s dolphins a year, while one recorded catching 44. ‘It was carnage in those days. We would find dead dolphins floating in the harbour. The deaths were huge. Hundreds, if not thousands, were being killed annually. It was pretty tragic at the time,’ says Elisabeth.
Elisabeth and Steve’s initial work prompted former Prime Minister Helen Clark (then Minister of Conservation) to declare an area around Banks Peninsula as New Zealand’s first marine mammal sanctuary in 1988 in a bid to protect the local Hector’s dolphin population.
More than a decade later, Jim Anderton introduced a comprehensive raft of protection measures to further protect Hector’s and Māui dolphins. Among the measures introduced was the establishment of marine mammal sanctuaries, and restrictions on set netting (gill netting) and trawling.
But while these measures were a step in the right direction, Elisabeth maintains the government didn’t go far enough, and it needs to act now to ensure the Hector’s dolphin is around for future generations to enjoy. ‘There is a very clear signal that in areas where there is no protection, the Hector’s dolphins are doing very badly, and where there’s protection, they are doing much better,’ she says.
Total dolphin population numbers do not give a clear picture. Downgraded from ‘endangered’ to ‘vulnerable’ in the latest marine mammal threat report released by the Department of Conservation (DOC), in reality, several populations have become incredibly small, says Elisabeth. Only about 45 Hector’s dolphins live in Porpoise Bay in the Catlins, 42 off Otago, two or three hundred in Te Waewae Bay on the south coast, and about 200 off the north coast of the South Island. ‘The nationwide population is becoming fragmented and is shrinking into the middle. Before long there will only be Hector’s dolphins left in the middle of the east and west coasts of the South Island, and eventually the whole species will be gone.’
Dolphins, as a group, are slow breeders. Female dolphins only produce one calf every two to four years and do not start breeding until they are seven to nine years old. Calves stay with their mothers for up to two years.
She says this slow rate of reproduction, combined with their relatively short lifespan (up to 25–30 years) means the population is particularly vulnerable to deaths caused by human activities, like fishing. And sadly, there are still far too many dolphins getting caught and dying in fishing nets.
A marine mammal, Hector’s dolphins live in the sea, but breathe air. Their lungs are small, roughly the same size as a human’s, so they drown in about the same amount of time as a human would if they get tangled in fishing nets.
Since last December, Fisheries Inshore New Zealand (FINZ) has reported seven Hector’s dolphins have died in commercial trawling nets, taking the total number of reported deaths (in Canterbury alone) to 12 over the past two summers.
‘Looking at where the dolphins live, and where set netting and trawling are still permitted, there is nothing surprising about these devastating, but all too predictable deaths,’ says Elisabeth. ‘It is literally a matter of when, not if. Curious by nature, dolphins are attracted to trawlers; they make a lot of noise, especially if they are bottom trawling, and for the dolphins, that’s a dinner bell. Dolphins will camp behind the trawlers for hours. It’s like playing in traffic. Most of the time they are fine, but every once in a while they find themselves in the wrong place at the wrong time.’
Meanwhile, set nets are indiscriminate, catching and drowning everything in their wake. They don’t just kill dolphins, but hoiho (yellow-eyed penguin), little blue and Fiordland crested penguins, shags, shearwaters, and terns. Initially, it was thought that thin nylon fishing nets were undetectable to the sonar signals sent out by dolphins, whereas now it appears they ‘turn off’ their echolocation in familiar areas, meaning they’re unable to detect the danger, she explains.
In the wake of the deaths in 2018, the government fast-tracked a review of the Hector’s and Māui dolphin Threat Management Plan, originally promised back in 2013. But frustratingly, action has been slow. The proposed Hector’s and Māui Dolphin Threat Management Plan finally came out for public consultation in June, with submissions closing this month (August). Elisabeth encourages all Kiwis to have their say. ‘If we act now, and do the right thing, we can turn things around and set a course for a sustainable future.’
The Yangtze River dolphin or baiji was the first cetacean species to be driven to extinction by human activity, and now Mexico and New Zealand are in a race not to deliver the next. The Mexican government has taken bold steps to save the vaquita porpoise. Yet to date, New Zealand has done little to protect the Māui and Hector’s dolphin, despite rising pressure from the international community.
Last year international conservation alliance, Mission Blue, declared New Zealand’s coastal waters as a Hope Spot. First launched by world-renowned oceanographer Dr Sylvia Earle in 2009, Hope Spots are intended to bring about a significant increase in ocean protection from less than six per cent today to 30 per cent by the year 2030. Members recently visited Banks Peninsula to see Hector’s dolphins in their natural environment.
Elisabeth says international pressure from organisations such as Mission Blue, the International Whaling Commission (IWC), International Union for Conservation of Nature (IUCN) and Nature and Biodiversity Conservation Union (NABU) was becoming an increasingly important way of shining the limelight on New Zealand.
‘The two fishing methods are known to kill dolphins all over the world,’ she says. ‘New Zealand is no different. It’s quite simple, and so simply avoided. There just needs to be a ban of gillnets (set nets) and trawling in dolphin habitat (less than 100 m of water and within 40 km of the coastline). There is nothing complicated or wicked about it, there is just a lack of political will.’
WORDS Annie Studholme IMAGES Guy Frederick