Coming back to the Auckland Islands is a bit like coming home. This is my fourth winter season since 2008 and the harbour feels as familiar as my neighbourhood in Auckland. This feeling is helped by the whale welcome parties that visited the MV Strannik while we settled into Erebus Cove yesterday afternoon.
As it was far too windy to work on the water, we prepared our gear onboard the Strannik and were treated to groups of curious whales coming close to the vessel. The tohorā would often roll on their side to get a better look at us. Down here, boats are a novelty to the whales, and it seemed like the tohorā wanted to check out their new neighbours.
There are particular neighbours we’d like to see this winter: Bill/Wiremu and Tahi, two of the whales we tagged last season. Tahi was transmitting up until a few days ago, just out of Port Ross. Bill is further north, but we hope he’ll come by for a visit. We have put a small receiver on the bridge of the Strannik that will beep if any of the transmitting whales come close. If that happens, hopefully the weather allows us to put up a drone and check out our mates.
Last year’s satellite tracked whales showed us that history was not a great guide to understanding how tohorā use their environment today. Whalers in the 19th century caught great numbers of tohorā in summer and spring to the east and north of Aotearoa New Zealand. However, none of the whales we satellite tracked in 2020 went there – instead they went as far south as Antarctica and as far west as the Indian Ocean (see https://www.tohoravoyages.ac.nz/ for their tracks).
Bill or Wiremu, a tohorā satellite tagged in August 2020, completed a whole migratory cycle and came back close to the Auckland Islands in June 2021. With his record breaking satellite tag still going as of July 2021, we can see Bill/Wiremu is heading southwest again, following a very similar path to last year’s migration.
We have now satellite tagged 10 whales this season. The last whale we tagged was a friendly whale that swam under and around the boat until it popped up in front of us in the perfect position to put a tag on. Of the 10 satellite tagged whales, indications are that two of them are already starting to follow Bill/Wiremu southwest to feed.
I had hoped that knowledge of those foraging areas to the north and east of Aotearoa New Zealand as good foraging grounds was still held by some of the population. However, perhaps it has been lost when whaling decimated the population. Or perhaps these northerly foraging grounds are known to only a few whales today. As we satellite tag less than one percent of the current population, perhaps we’re just yet to follow the whales that know that particular area. In any case, I’m excited to follow the voyages of the 2021 satellite tracked whales – who knows what surprises they will have for us this year!
This year we arrived in Port Ross in late June, the earliest an expedition has been here since 1998. What we found is what Natalie Patenaude and her colleagues found over 20 years ago: a whole lot of socialising southern right whales.
What we see when southern right whales socialise is a group of whales – perhaps more than 15 – rolling around at the surface. When you’re sitting in a boat watching these groups, what you notice is the random body parts that come up to the surface. It might be a head, or it might be a pectoral fin, or the belly. Once you understand how the whales are oriented in the water, you often realise that they are stroking each other and what looks like cuddling. Sometimes the whales can get boisterous. This can mean breaching, when 50 tonnes or so of whale launched into the air and splash down, often several times in a row. Sometimes one whale, probably the female, will swim off away from the group, with the rest of the whales following. That’s because these groups are most often mating aggregations; there will be a female in the middle, and lots of males rolling around trying to get close to her.
In southern right whales, females only breed once every three years, but males can breed every year. So this means that there’s competition amongst males for the perhaps one third of adult females that are going to breed in a given winter. Across the animal kingdom, males compete for opportunities to breed in different ways. In some species, males might fight for control of some resource that females use, like suitable breeding or feeding habitat. If they control this habitat, they get to mate with the females in the area.
Southern right whale females are bigger than males, and the habitat in the Auckland Islands is abundant and hard to control. So male southern right whales don’t really fight, but instead compete via their sperm. Southern right whales have the largest testicles in the animal kingdom, up to one tonne, and mating will occur multiple times in these socialising groups. The males with the highest quality sperm – perhaps the best swimmers, or the biggest amount – will sire the next generation.
So while we see lots of socialising early in the season, we also see the outcome of last year’s activities: a few small calves with their mothers. As the season progresses Port Ross will fill up with more and more calves, and the number of social groups will decline. Most wintering grounds are either nursery or social grounds, not both, which makes this a unique place where we can study the whole population.
I think of southern right whales as traditional kind of whales. They like to stick to the migratory patterns that their mums taught them; typically going to the same wintering ground to breed and the same summer feeding grounds to eat.
Kai is important to whales like southern rights: that summer feast provisions them and sustains their calf through the winter fast. And those calves are big – they are born at 4 or 5 m long and grow a metre a month. Clearly, having good kai means big mums who can support growing and healthy calves.
So when South African right whales started turning up on winter breeding grounds in the lowest numbers in decades, the first question was: where are they feeding? Is it changing? Can our traditional whales change as well?
Using microchemical markers called stable isotopes, we were able to look at where South African southern right whales were feeding over the past three decades. During the 1990s, the South African population was growing well the stable isotope data suggested they were feeding mainly on krill from South Georgia/Islas Georgias del Sur. In contrast, over the last 5 years, South African right whales have been having babies less often and the stable isotope data suggest that the whales are now feeding much further north, and are probably feeding on a range of krill and copepods.
On one hand this is good news; southern right whales can innovate and change their feeding traditions. The bad news is that this change hasn’t resulted in a benefit to the population – recovery has slowed. The optimist in me hopes that as the whales try new feeding strategies, they will discover new ones that provide more kai, leading to more babies and recovery. However, as the oceans continue to change, it could be a continual challenge to keep up with changing prey distribution.
Southern right whales are considered a sentinel for climate change by the International Whaling Commission – Southern Ocean Research Partnership. This is a group of scientists from around the world trying to understand how whales will fare in a changing ocean. Our work on South African southern right whales suggests that some are struggling to keep pace with climate change.
What does this mean for tohorā nō Aotearoa – New Zealand southern right whales?
Recent work by Otago University and others showed that tohorā are the fattest right whales in the world – suggesting they are getting plenty of kai. North Atlantic right whales, a Northern Hemisphere cousin to the southern species, are doing the worst. Although the North Atlantic right whales are also shifting their distribution, possibly also to find kai or avoid human activities, and this is leading them into trouble. About 1/8 North Atlantic right whales have died over the past couple of years, most due to ship strike and fishing gear entanglement, over the past couple of years. These skinny and scarred whales need a respite from human impacts to survive.
How are our whales doing so well but South African and North Atlantic right whales struggling? It is probably down to where and on what they are feeding – which we are still learning about.
Historically, tohorā were killed in summer and spring months east and north of New Zealand. However, satellite tracked whales from the Auckland Islands Maungahuka are actually migrating west – after 130 days of tracking, Wiremu/Bill the tohorā is west of Australia and still heading into the Indian Ocean.
Next year is the second and final field season for the tohorā project. We hope to tag more tohorā to bring the total to 20 tagged over 2 years. In addition, we are doing the same kind of stable isotope analysis as we did for the South African right whales – but using data from the 1990s, 2000s and 2020s. We hope to get a good picture of where tohorā are feeding, and how their feeding grounds and prey will change over time. By comparing the behaviour and recovery of different whale populations, we can start to understand what strategies will help them recovery from whaling in uncertain seas.
Find out more:
The paper, led by Gideon van den Berg who was co-supervised by Drs Els Vermeulen, Luciano Valenzuela and Emma Carroll, is out now in Global Change Biology.
As we’ve been here nearly 2 weeks, we’re getting to know the whales in our neighbourhood. There are particularly striking ones that we have been recognising and greet like an old friend when they pop up next to us.
The most striking ones are the white calves. About 1 in 20 Aotearoa New Zealand southern right whales are born white with black splotches, and grow into grey coloured adults. The white colour can be seen for miles on a clear day, but it is easy to tell the three that we’ve seen apart. For example, one of the white calves has a black collar, that is a ring of black colouration just below its blow hole. Another white calf has more of a black belt – black colouration further down its back.
White calf with black collar, photo credit UOA Auckland Islands Research Team
Some adult southern right whales have white patches that also make them quite distinctive. This is one we called lightening, as it was jet black except for a white zig zag pattern on its back.
Whale with zig zag colouration on its back, photo credit UOA Auckland Islands Research Team
One of the most distinctive whales we have had in Port Ross is knobbly back, named after the pronounced bumps along its back. This could be a deformity, as the skin on top of the bumps looks healthy, rather than scarred as you might expect if it was the result of ship strike. Knobbly back was sighted on our first day of fieldwork, 1 August, and we were able to get a small skin sample from it on 8 August.
Knobbly back, photo credit UOA Auckland Islands Research Team
As well as helping fund this research, marine conservation organisation Live Ocean has launched a whale sighting campaign around mainland NZ to help add to our knowledge about where these whales go. For more information on the research or how to report a sighting go to www.liveocean.com
Working in the subantarctic in winter has its challenges, but we are lucky to live aboard the ESV Evohe while down in the Auckland Islands. This vessel is our home, office and makeshift lab while in the field. This office doesn’t have broadband, however, so twice a day we use satellites to download emails and get the latest weather forecast.
Evohe and whale, credit to Richie Robinson
The weather is the biggest factor in what we do. I make a rough plan – well, several plans to be honest – in the evening for what we’ll do the following day, based on the weather forecast and potential variations thereof. So far we’ve had better weather than forecast with some beautiful days. It could easily go the other way.
If the weather is good enough, our office for the day is a zippy little boat. This allows us to easily move around Port Ross and work with the whales, but unlike the other animals living down here, we don’t have fur, feathers or blubber to keep the cold out. So we need to ensure we have the right gear to stay warm and dry. Antarctica NZ have kindly lent us some snazzy bright orange mustang suits: these are basically well insulated onesies that we can put over top of thermals and fleeces and underneath a rain jacket. Personally, I have been wearing 4 layers of trousers and 5 layers of tops, as well as typically two pairs of gloves and a beanie. This clothing blubber layer is doing a good job at keeping me warm.
Getting our blubber on, credit Richie Robinson
For the past few days it’s been a bit squally, and you can see the weather coming down the harbour. In between shower and hail, we have been able to do some drone work, measuring how fat the whales are, and linking it to small skin samples that we collect using a remote biopsy system. This use of drones is one of the next steps in our work compared with 10 years ago, but it’s really linking with these small skin samples that I’m excited about. The small skin sample will tell us who they are, who they are related to using genetics; where they are feeding using microchemical markers called isotopes; and even how old they are using small changes in the DNA accents over time. I’m hoping we can see how fatness and how many babies a whale has correlates with age, feeding grounds and genetic lineages.
Whales in the mist: coming back to Auckland Islands
Coming to the Auckland Islands/Maukahuka is like travelling back in time as well as across the ocean. The hills are clad in rata forest, often shrouded in mist, and hoiho and New Zealand sea lions swim through the sheltered harbour of Port Ross. As someone who always wondered what Aoteroa New Zealand looked like before people arrived, it’s a joy to be somewhere that gives us a glimpse of this history.
Misty morning at the Auckland Islands, credit Richie Robinson
It’s this lack of people that made it the most important winter habitat for tohorā in Aotearoa New Zealand’s waters. While people hunted and killed those whales that made mainland New Zealand their winter home, some tohorā managed to find refuge down here in the Auckland Islands. Those tohorā had babies, who then returned to the Auckland Islands to breed as well. And that’s one of the most striking things about being back here this winter, compared with last time I was here 10 years ago: there are so many mums and calves! In previous years, there was more of a balance between mums and calves and social groups/single whales. It could be due to timing: pandemic related delays mean we are here several weeks later than in previous surveys. Perhaps some of the socialising whales have already come through.
Mum and calf southern right whale, credit Richie Robinson
Don’t get me wrong, I’m not complaining. Lots of babies is a good sign of a growing population. And tohorā mums are wonderful and tolerant mums; they rest at the surface while their babies swim around them, slap them with little flippers, they lie on their backs while baby rests on their bellies. It is pretty adorable. These mums also invest a lot in their babies: in the first few months of life, the whales will grow a couple of centimetres per day while mum’s size shrinks by about 25%. I’m looking forward to seeing how many of the mums we see today were calves we saw in previous expeditions. The first expedition to the Auckland Islands by the University of Auckland was in 1995, and annual surveys were conducted during the winters of 1995-1998 and 2006-2009. Based on genetic samples we collected in previous expeditions and today, we’re able to see a continuation of the lineages that found refuge here from whaling.
As well as helping fund this research, marine conservation organisation Live Ocean has launched a whale sighting campaign around mainland NZ to help add to our knowledge about where these whales go. For more information on the research or how to report a sighting go to www.liveocean.com
Today we had to get up at 5 am, but it was all good because today is Departure Day! It’s one of the most exciting milestones in any field trip which, especially in a pandemic, are basically like planning the most complicated trip you can think of. It’s a choreography of people, paperwork and gear, 3 years in the making. Here is the picture of the happy team having made it to departure day:
From left to right: Bill Morris, Emma Carroll, Leena Riekkola, Esther Stuck, Rochelle Constantine, Ros Cole, Simon Childerhouse and Richie Robinson behind the camera.
Today was a classic race against time, with the aim to get from Dunedin to Invercargill and back before sunset. Invercargill is where the DOC Biosecurity check takes place, an important biological control measure as the Auckland Islands is a unique environment, so any seeds or dirt on our clothes could bring an unwelcome visitor. But it also means that some strangers have to go through all our gear, including unpairing and repairing every sock.
A 5:30 am departure meant that even including a stop for a breakfast of champions, Fat Bastard Pies, we got to the DOC quarantine office by 8:30. The DOC staff did the gear inspection and briefing with care and alacrity so we made it back to the Evohe by 3pm, the return journey fuelled by Gore Oven Fresh Bakery.
Having sent gear to the quarantine office ahead of us, we literally had ALL the gear, and required a cargo van plus giant people mover to get it all to the boat.
We’ve got a lot of science to get done, and have a lot of experienced people onboard with the expertise to do it: from drone pilots, to photo-ID, to genetic sampling and satellite tracking. They’re all kiwis or residents, so even in the pandemic this project was possible. It’s now the evening and we’re all settled onto the Evohe, gear stashed, relaxed and looking forward to getting to the Auckland Islands.
As well as helping fund this research, marine conservation organisation Live Ocean has launched a whale sighting campaign around mainland NZ to help add to our knowledge about where these whales go. For more information on the research or how to report a sighting go to www.liveocean.com
