An acoustic 'harassment' device won’t be used to keep dolphins from high-speed boats, reports David Williams.
Organisers of a super-fast boat race have scrapped plans to use an underwater noise device to scare dolphins in a marine mammal sanctuary.
SailGP’s consultants, Enviser, lodged an application with the Department of Conservation (DoC) in December to use the controversial devices – known as “seal scarers” in Scotland and dubbed “harassment” devices by dolphin advocates – which emit high-frequency noise to ward off marine mammals.
Next month’s event, to be held in Lyttelton Harbour/Whakaraupō, over the hill from Christchurch, involves foiling catamarans capable of speeds of up to 100kmh. Another 40-50 support boats are expected, as well as more than 150 spectator boats on race days – all in an area that’s part of the Banks Peninsula marine mammal sanctuary.
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Nationally vulnerable Upokohue/Hector’s dolphins are known to be in the harbour at all times of the day, in all months of the year, and their calves are regularly seen there each summer.
SailGP’s application, lodged with the Department of Conservation on December 13, sought permission to trial underwater acoustic deterrent devices in Pegasus Bay to deter marine mammals, and use them during the event, being held between March 15-19.
DoC permissions regulatory delivery manager Judi Brennan confirmed the application was withdrawn this past Wednesday, without saying why.
She added: “These devices were proposed as an additional measure in the marine mammal management plan for the event.”
Local hapū were more forthcoming.
“Te Hapū o Ngāti Wheke supports the technical advice of the Department of Conservation which led to SailGP’s decision to withdraw its application to use an acoustic deterrent device,” said Yvette Couch-Lewis (Ngāi Tahu – Ngāti Wheke, Ngāti Waewae), chairperson of the SailGP marine mammal management plan advisory group.
SailGP New Zealand event director Karl Budge says use of the device, proposed by experts, was supplementary to “an already robust plan”. It would only have been used when no dolphins were detected acoustically within or near the race area.
“Based on the advice of DoC and other experts, we maintain full confidence in the efficacy of the plan for the event in March, which will go ahead without the device in place.”
He adds: “Withdrawing the permit this year, with a view to exploring future research, will enable more time to test the device and fully understand the unique response of Upokohue Hector’s Dolphins.”
The event is set to return to Lyttelton Harbour in 2025.
SailGP’s marine mammal management plan was developed with input from experts, hapū, and under the guidance of Te Roopū Tiaki Whakaraupō advisory group.
ChristchurchNZ, an economic development agency, signed off the plan. Somewhat uncomfortably, it also paid millions for the rights to host the race in the hope of promoting the city to millions of viewers.
Tracey Wilson, ChristchurchNZ’s acting general manager of destination and attraction, says in a statement the plan will continually evolve “to maintain best practice with the latest technology available”.
“We note that DoC have shared with us that they are pleased with the range of protection measures in place, and excited about the legacy project around the development of real-time acoustic detection devices and the protection benefits these will bring to dolphins in other harbours globally.”
Withdrawal of the devices has left dolphin advocates with mixed feelings.
“I’m not surprised they’ve actually thought, Well, that’s a bad look,” says Michael Lawry, managing director of conservation group Sea Shepherd NZ.
“The concept of using a dolphin deterrent device in a marine mammal sanctuary seems really contrary to the original idea of what a refuge is.”
It comes at a time when New Zealand’s protection of dolphins is in the international spotlight.
Late last year, the US Court of International Trade ordered a ban on some fish exports from Aotearoa, after Sea Shepherd argued the Government wasn’t doing enough to protect critically endangered Māui dolphins.
Yet, Lawry says, our standards are dropping by allowing SailGP to race in a marine mammal sanctuary.
“All we’re doing is just introducing more risk into an area where these marine mammals are supposed to be protected.”
Retired marine biologist Liz Slooten says the deterrent – she calls it a harassment device – would have been harmful, and “potentially just made a bad thing even worse”. But not using it leaves in place the event’s other problems, she says.
SailGP’s marine mammal protection plan – released publicly just days before Christmas – says it’s “highly likely” dolphins will be in the harbour during the race.
“Upokohue/Hector’s dolphins are naturally inquisitive mammals and will approach and interact with vessels.”
The plan lists “the best practicable mitigation and protection measures”, including land-based observers, pre-race boat surveys, drone surveillance “if feasible”, underwater monitoring with hydrophones, and an “acoustic deterrent device”. Some detail is redacted.
“It would be like a UFO landing in a children’s playground or a forest with kiwi in it.” – Liz Slooten
But, according to the plan, several proposed mitigation measures will likely be ineffective.
Drone surveillance is not expected to be used during races “due to the events’ broadcast requirements and the associated need for airspace”.
Underwater acoustic monitoring is “not considered useful”, the plan says, because of the noise and activity of support and spectator vessels.
Dolphin sightings by the public and race staff logged on an app will not be shared in real-time.
Slooten, a dolphin expert, says that leaves SailGP with spotting the animals visually or acoustically during the “circus” of a boat race, with whitecaps on the water and potentially boats in the way.
“From our own work, it is clear that visual observations only count a small percentage of the dolphins present [as] they are underwater about half of the time.”
Acoustic detections will be difficult, Slooten says, because Hector’s dolphin sounds are high frequency and only travel a short distance underwater.
“Even the fanciest sound recording gear won’t solve that basic physics problem.”
SailGP’s high-speed, versatile catamarans have hulls and appendages that travel through the water at depths of up to 2.5m.
Slooten says Upokohue in Whakaraupō would never have encountered anything like it – the type of boat, the noise, the speed, and the scything nature of the foils.
“It would be like a UFO landing in a children’s playground or a forest with kiwi in it,” Slooten says.
“An acoustic harassment device would have been like shining a bright light in the kiwi’s or children’s eyes and then expecting them to run out of the way before the UFO hits them.”
Extra layer of protection
SailGP’s emailed response to Newsroom’s questions ran to more than 800 words.
Echoing comments from DoC’s Brennan, Budge, the event director, said the underwater acoustic deterrent device was “proposed as an extra layer of protection”.
(SailGP’s marine mammal management plan from December names the device as one of 10 “resource requirements”, which are prefaced by the words “Implementing the plan requires the following”. However, the document is subject to change.)
The device was to be positioned near the edge of the racecourse – “and activated only when no dolphins are detected acoustically via passive acoustic monitoring devices, or visually by observers, within, or near, the race area”.
Budge says the marine mammal management plan has been developed over the last two years, with DoC a “key contributor”.
“It was on DoC’s technical advice that SailGP decided to remove the application in order to enable additional research and testing in a New Zealand context before a scheduled race event.
“SailGP first learned of DoC’s position that more testing was required before a permit could be issued through its consultants late last week.”
Event organisers met with DoC this past Wednesday to “understand the process and formalise our withdrawal”.
A DoC-commissioned review of acoustic deterrent devices, published in 2020, said limited trials with Hector’s and Māui dolphins in New Zealand produced “ambiguous results”, but there’s some indiction Hector’s display “avoidance behaviour”.
Because our endemic dolphins aren’t neophobic – they don’t fear new things – the devices may be less effective, the report said – “but this requires testing to confirm”.
(The DoC report was reviewed by Cawthron Institute’s Deanna Clement, a marine mammal expert who also contributed to SailGP’s marine mammal management plan.)
Budge says the devices are used commonly overseas “to keep marine mammals away from dangerous situations”.
They’ve certainly been used in Scotland to deter seals (which are pinnipeds, the same family as walruses and sea lions) from attacking fish farms. But their use there was controversial and they were effectively banned from being used on Scottish fish farms last year.
NatureScot, Scotland’s government-advising nature agency, commissioned a report to establish the sensitivity of seals and cetaceans (whales, dolphins and porpoises) to acoustic deterrent devices (ADDs), used in aquaculture.
The report, published in 2014, said there is a “credible risk of exceeding injury criteria for both seals and porpoises”, given modelling of exposure times at given ranges from active devices.
“The risk that ADDs at Scottish aquaculture site is causing permanent hearing damage to marine mammals cannot be discounted.”
“If you hit a dolphin at high speed, or you get one in a fishing net, it's all over.” – Michael Lawry
A 2021 Scottish study reportedly found the accumulative level of noise from the devices could result in the temporary impairment of harbour porpoise hearing for up to 17 miles away from a fish farm.
As Slooten points out, dolphins use sound for everything: “Communication, finding their way around, finding their food.”
It’s unclear how Hector’s dolphins would respond to such a device, but two possibilities, she suggests, are they stop clicking, making them more difficult to detect, and the device noise makes it harder for them to detect obstacles, including boats, and communicate with each other, including mother and calf.
SailGP’s management plan says newborn dolphins and young animals are more vulnerable to boat strike, “as they are less aware of risk, spend more time on the surface and dive more slowly than mature dolphins”.
The increase in noise and vessel traffic from support and spectator boats may help deter marine mammals from the race area, the plan says.
While SailGP is confident in the efficacy of its plan, Sea Shepherd’s Lawry says it seems to be confusing protection with monitoring.
“Whether we're flying drones or unicorns, or we've got more observers on board, it's all after the fact. If you hit a dolphin at high speed, or you get one in a fishing net, it's all over.”
Everyone seems to agree the death of a dolphin is possible.
The preamble in SailGP’s management plan says: “It is important to note that this plan uses a range of methods to reduce risks but does not entirely eliminate all risks.” The plan’s authors explicitly state they will not be liable for any incident involving Upokohue/Hector's dolphins or other marine mammal.
Race organisers have response protocols in place if such a tragedy unfolds.
Under the Marine Mammals Protection Act, it’s an offence to harass, disturb, injure, or kill marine mammals. Individuals convicted of an offence can face up to two years in prison and a $100,000 fine, while corporates can face fines of up to $200,000.
But if the worst happens in Lyttelton Harbour, Sea Shepherd’s Lawry is convinced there’ll be no consequences.
“They’re going to go, ‘Well, we signed off on this plan so it’s out of our hands now – we did our best’.
“They shouldn’t really get approval in first place if they’re introducing more risk.”
