Errands and celebrations

Julie fixing a Dtag in the lab. (Luis Lamar, Advanced
Imaging & Visualization Lab, WHOI)

Today we had a number of errands to take care of on shore. First, two of us went up in a local helicopter to listen in vain for a missing tag. The hexacopter crew also went ashore for more trials with Bubby, and to track down parts for Archie, Bubby's elder brother.

Bubby flew really well (proudly watched over by his namesake, the Alucia deckhand), so they then tried to launch from the ship's tender. That also went well, except that catching a hexacopter by hand in any kind of swell is difficult. They've concluded he needs to be fully amphibious to allow a water landing near the boat .

After our errands were finished, we headed offshore to deploy the breathalyzer, as there was less swell than yesterday.

But the whales had different ideas, zoo we called it a day at a remarkably early 5:30 p.m. and headed to the ship to celebrate . . .

My Birthday on a Boat 
by Julie van der Hoop (WHOI/ MIT Joint Program PhD student)

Julie celebrating with friends. (Moira Brown,
New England Aquarium)

Today is my 25th birthday, and how better to spend it than at sea, surrounded by marine mammals, enjoying beautiful weather, and celebrating with new friends.

After a late night spent with DTAG data I decided to sleep in until 7:00 a.m.--a luxury for sure. But what was even more luxurious is the fact that I had a chance to squeeze in a workout while Bubby was on a test flight in calm winds in Kaikoura Harbour. Nothing beats the view from the elliptical on the Alucia.

Julie's card. (Jerry Conway, Canadian Whale Institute)

With calm waters in the harbor, we headed out in a Zodiac to photo-ID some inshore whales. Will, Marta, Leigh, and I were lucky enough to come across two whales, one that we had previously tagged. We were also keeping an eye out for skin samples to collect for stable isotope analysis to determine the diet of sperm whales in these waters.

Scanning the water, we saw no skin but skimmed up some mystery substance to try to figure out just what it was. As it turned out, on my birthday, I sat on the side of the Zodiac, holding whale poop (specifically partially digested squid mantle, we think) in my hands. Few people can say that.


I spent a fantastic afternoon on the fly bridge spotting blows, directing the small boats, watching the "breathalyzer" in action, and enjoying the austral summer weather.

Marta Guerra holds a sample of semi-digested
squid found in the feces of a sperm whale.
(Julie van der Hoop, WHOI)

At dinnertime, I was presented with a delicious (and vegan!) cake along with a card signed by the science team and ship’s crew. A Canadian colleague who wasn’t able to join us on the trip had done a fantastic drawing and had sent it by email. Everyone on board has made me feel extra special today, and has gone out of their way to spread the birthday love!

And as for a gift? Today, I came so close to fulfilling one of my life goals. Leigh spotted a blue whale, but try as he might, wasn’t able to spot its next surfacing. Though I’ve seen new species this trip (southern right whales, dusky dolphins, New Zealand fur seals), I can’t count a blue whale that I didn’t see.

Maybe on my 26th birthday.

The whale brethalyzer

Today we went up the hill again to listen for the missing tag in vain. Bubby, the aerial camera, got a work out from the ship's tender (he needs more work) and the breathalyzer got an inshore trial. Then went offshore about 12 miles southeast of the Kaikoura Peninsula and found a whale in some large swells, but decided that the breathalyzer needed a calmer day for its first deployment. We were able to attach a tag, however.

Diving marine mammals live a life of dual constraints. One the one hand, they want to maximize their time underwater to increase foraging success and the number of prey captured. On the other hand, they need to return to the surface to replenish their oxygen stores, which they use to generate energy while underwater.

In a changing environment, where prey density may have been reduced either by overfishing or increasing temperature of surface waters, marine mammals may have to dive longer to catch enough food to survive. Consequently, oxygen management becomes the limiting factor in the time they can spend underwater and, consequently, the amount of food they can capture during each dive. For this reason, physiologists are interested in measuring the metabolic rate, or the rate of oxygen consumption, in marine mammals.

In smaller, captive species, physiologists can measure expired oxygen fairly easily and, from this, estimate the metabolic cost of longer dives. Measuring the oxygen consumption in large whales, on the other hand, has been a bit more difficult. To do this it is necessary to measure to volume of air exhaled in a unit of time and to determine the composition of the expired gas.

To measure the amount and composition of air a sperm whale exhales, we have to place a flow meter and gas analyzer directly over the animal's blowhole when it exhales. To do that, we have to come within a few meters of a while while it is at the surface—not an easy task when you are dealing with an animal that may weigh up to 40 tons that swims at one or two knots in an open ocean with varying swell.

Mike Morrissey, New Zealand Department of Conservation
wearing a helmet camera. (Luis Lamar, Advanced Imaging &
Visualization Lab, WHOI)

We have had the opportunity to learn how to approach these giants in kayaks from our colleague Mike Morrissey at the Department of Conservation. This approach first involved transporting a kayak close to a whale by small boat. After launching the kayak, we approached the whale from the side until we were within one or two meters, at which point we were going to extend a pole to measure and sample the exhaled air.

On the second day of the cruise, we practiced approaching a whale and came within four or five meters before the animal increased its speed and finally decided to dive. During the days that followed, we came closer but realized that managing electronic equipment and a six-meter carbon fiber pole while at the same time paddling next to a whale would minimize our chances of placing the flow meter over the blowhole successfully. Instead, we will attempt close encounters with the whales using one of the small boats. For this purpose, we have rigged one so that we can extend our reach with the precision we need to capture the exhaled gases. We are now waiting for calmer sea conditions so we can test our idea and possibly be the first who captures the exhaled gases of a sperm whale.

Micah Brodsky with the Mark 2 Whale Brethalyzer
(Luis Lamar, Advanced Imaging & Visualization Lab, WHOI)

To measure the volume of expired air we are using a custom-made flow meter, which we have named the whale breathalyzer. BRETHALYZER The breathalyzer is secured to the end of a carbon fiber pole and connected to a pressure transducer that measures gas flow. It also includes an oxygen and carbon dioxide analyzer, which measures the gas composition of the expired air.

The captured air will allow us to estimate the amount of oxygen consumed during the whale's previous dive and get a better picture of the work it to capture its prey. Once we have captured expired air from several whales, we can examine work effort using the DTAG data and create a better picture of how much energy it takes to capture a giant squid.

After fabricating several prototypes from a variety of materials, this second-generation prototype was designed and built out of carbon fiber. The experience, hard work and dedication of the folks mentioned below made it possible to take an idea and transform it into a completed prototype in a record five days.

Dr. Brodsky and Dr. Fahlman would like to thank Trevor and Penny Austin at PaxArms; and Andy, Davie, and Jenny from Davie Norris Boatbuilders.

The routine

We have been on this cruise for a week now. Maybe it is time for a bit of a recap to describe how our routine has been shaking out, and what we all get up to all day.

By dawn the ship heads to a spot in the mouth of the canyon where we hope to find whales. The sun gets up around 6:30, which also reveals bleary-eyed scientists in the mess fixing their favorite blend of cereal, yogurt, fruit, etc, given that the heartier fare isn't set out for a while yet. Whether they got much, if any, sleep the night before depends on if we were tracking a tagged whale or looking for a released tag overnight.

Another day, another tag. (Luis Lamar,
Advanced Imaging & Visualization Lab, WHOI)

Regardless, our trusty scouts, usually Will, Marta or Moe, and Andreas then head off in the ship's tender with one of the ship's crew to listen and look for whales, while we also set a visual watch on the top deck. We take turns at this. Often by 9:00 or 9:30 they have started tracking a whale or two, so it's time for the Zodiac crew to mobilize: Leigh and Julie the taggers, Luis the camera guy, and Michael the driver.

We suit up and head off to join the tender, shut down the engine while Will and Marta determine where the whales are headed. We follow suit, heading in the apparent direction of the clicking and stopping to listen every while. When a whale goes silent ,we start to look out over the water in earnest.

Often, the first to see the whale blow is the person on the top deck of the ship. The Zodiac crew then moves over into a spot behind the whale, slows down, sets a tag on the end of the pole, checks that the ship can hear the radio transmitter, and then ever so gently creeps up behind the whale. Finally, if the whale lets us, we can gently place the tag on its back. If it does not want us there it quickly becomes obvious and we move on to another whale and start all over again.

Once the tag is on, the Zodiac crew returns to the ship and we start radio tracking the whale. A whale will usually surface every hour, at which time we can hear the beeping associated with a surfaced whale, and thus stay with it.

Meanwhile, the ship's tender heads off to look and listen for other whales to get photo-ID images and a better sense of where in the canyon the whales can be found. Once the tag attachment time has elapsed—usually 3 to 6 hours—the tag detaches and slowly surfaces, at which point we detect a continuous beeping that helps us direct the ship so that we can scoop the tag with a dipnet and start downloading the data.

A white-capped albatross taking flight (Luis Lamar,
Advanced Imaging & Visualization Lab, WHOI)

Meanwhile back in the lab, Wayne and Don are busy with their aerial camera system. Archie is still waiting for parts to be delivered, while his buddy, who today was christened Bubby after one of the ship's deckhands, is almost ready for prime time. The plan is to test fly Bubby off the ship's tender tomorrow. Andreas and Micah are also busy with version two of their breath-sampling device. That, too, may see prime time tomorrow if inshore trials go well.

Today we were surrounded by many Buller's Mollymawk, a local albatross.

The DTAG

This afternoon, we finally found an animal that was approachable and attached a tag programmed to release in 6 hours, so we hope to retrieve it before midnight tonight. While we wait, watch, and listen for the signal that it is on the surface, here is some background about the tags.

Our oceans are not only vast, but also deep. Some marine mammals have evolved the means to exploit resources and ecological niches far beneath the surface.

This is no mean feat, as the deep ocean is an inhospitable place, with cold temperatures and extreme pressures. As an object descends in the water column, the pressure it experiences increases by one atmosphere with every 10 meters. Thus, an animal that dives to 1,000 meters experiences 100 times more pressure than when it as at the surface.

To study deep diving odontocetes—toothed whales such as sperm whales, beaked whales and pilot whales—that forage at depths in excess of 1,000 meters (where no scientist can easily follow), novel techniques are needed to document their behaviour. One such method is to attach data logging devices capable of surviving the rigours of deep ocean exploration. Engineers at WHOI developed just such a device, known as a DTAG, that is able to digitally record movement and acoustic data (Johnson & Tyack 2003).

Three-dimensional dive profile

The DTAG is a non-invasive, cell-phone-sized tool that contains a suite of sensors that includes either a single or a pair of hydrophones (underwater microphones), three magnetometers, three accelerometers, and instruments that record temperature and pressure. These sensors are able to record data 50 times per second, the result being incredibly fine-scale, high-resolution data that can shed a detailed light on a tagged animal’s three-dimensional movements while carrying the tag. The hydrophone in the DTAG is able to sample at a rate of up to 192 kHz and records all the sounds the tagged animal makes and the sounds that it hears while moving through its environment.

Attaching a DTAG. (Luis Lamar, Advanced
Imaging & Visualization Lab, WHOI)

In order to attach the DTAG to a whale, it is placed in a fairing that contains floatation foam, a VHF transmitter, and four soft suction cups and attached to the end of an eight meter carbon fiber pole. A team approaches slowly and quietly in a small boat to minimize disturbance to the whale at the surface. As the body of the animal rises up out of the water the team member on the bow of the boat attaches the tag to the dorsal surface of the animal. The tag is attached to the dorsal surface of animals. After a pre-programmed length of time, the suction cups release automatically.

The capabilities of the DTAG have enabled scientists to shed new light on the diving, fine-scale foraging, and acoustic behaviour of many marine mammal species. It is now helping us to investigate the behaviour of the large male sperm whales of Kaikoura.

1,400 meter dive

The sperm whales here in the Kaikoura Canyon begin making echolocation clicks soon after they "fluke up" to start a foraging dive. As they descend into the depths they produce loud clicks. By interpreting the echoes that return, the sperm whales are able to navigate beneath the surface and detect prey in the darkness beyond the reach of sunlight. So far, our tagged whales have dived to depths of almost 1,400 meters to feed.

The echolocation clicks that the whales produce have a rhythmic nature to them and can be heard for many miles. When potential prey, such as squid, are detected the sperm whales home in on their quarry and then switch from the regular echolocation clicks to a rapid sequence of clicks known as a "buzz" as they attempt to catch their prey. After foraging for almost an hour, the sperm whales return to the surface to breath before heading back to the larder of the abyss once more.

Frequency spectrogram of a
click-buzz sequence.

By attaching the DTAG and analyzing the natural sounds made by the whales, scientists are able to provide previously unavailable perspectives on the three-dimensional nature of their foraging behaviour. Such data can be used to fill information gaps about diving behaviour that can, in turn, be linked to foraging. In particular, how whales exploit the water column during foraging events and how animals respond to the ever-increasing presence of human-produced noise in the oceans. 

Reference
Johnson, M. and Tyack, P. L., "A digital acoustic recording tag for measuring the response of wild marine mammals to sound," IEEE J. Oceanic Eng, 28 (2003), 3-12.

How to radio track a tag

It seems the whales have wised up today.

We worked with a couple this morning and another this afternoon and each one was less cooperative than in previous days. But they were smaller animals and so perhaps less tolerant of our presence. Plus, we are using a tag with an extra piece to it, which makes it less easy to deploy. So we struck out today in terms of tagging.

We did, however, get good photo-ID images of three animals and a skin sample—a total of five so far, which is beginning to look like a sample set worth looking at for the planned dietary studies.

Julie van der Hoop listens for a tag.
(Luis Lamar, Advanced Imaging & Visualization Lab, WHOI)

Perhaps this is a good time to tell a bit more about how we recover the tags. Because they are slightly buoyant, the tags slowly rise to the surface after releasing from a whale. Once at the surface, their radio transmitter broadcasts a steady beeping, which we can hear using directional antennas (hand-held and installed on the ship) and a suitably tuned radio. With these, we can acquire a bearing on the tag and move in that direction. As we approach the tag, the signal gets stronger and stronger.

The signal of a tag floating at the surface is very different to one from a tagged whale. While on a whale, we detect a periodic chirp or two as the animal it is on surfaces every 45 to 60 minutes, especially as the whale arches to dive; once on the surface, the tag beeps continuously. Once we get a visual sighting of a tag in the water, which is by no means easy, we then maneuver nearby so we can retrieve it using a dipnet.

Leigh Hickmott detects the missing tag.
(Marta Guerra, University of Otago)

The other day, we had to leave a recalcitrant tag on a whale (one that we'd been trying to recover for two and a half days) and head for shelter. Once on shore, we climbed the nearest hill to get a better vantage point to listen for the tag. There was jubilation when we finally detected it, and we carefully took a bearing so the ship could run down the bearing to relocate it. Once back on board the sense of relief was palpable. It had been stuck on the whale for 36 hours or more and it had been causing more than a little loss of sleep.

Leigh Hickmott retrieves the errant tag from the bow of the ship.
(Luis Lamar, AIVL, WHOI)

So that might give you a bit more of a sense of the various skills our team has: radio tracking, tag application, photography, boat driving, microelectronics, data analysis—and a boat load of patience.

Tonight our aerial imaging team will test fly their new bird on shore so that it can get a sense of which way is up before it gets to fly off the ship tomorrow. Hopefully. Some of you older comic readers might have a sense of what it has been christened.

Figuring out who’s who in the Kaikoura Canyon

Today played out at a slower pace than yesterday. The stuck tag remained elusive and the weather precluded any thought of small boat activity, so we retreated to the town of Kaikoura for the night.

Our tracking crew climbed a hill and were able to get a bearing on the missing tag had finally released from its whale. So we all went back out in the Alucia, homing in on the tag's signal, and were able to recover it. The malfunction had been caused by seawater entry into the tag. It is now winging its way to Woods Hole in the hope that it has retrievable data.

Today was a relatively quiet day, so we thought we'd give you some background on why it is so useful to photograph marine mammals so carefully and systematically.


Figuring out Who’s Who in the Kaikoura Canyon: How sperm whales tell us their stories

A sperm whale surfaces after a long dive

The ability to identify an individual whale from photographs, or photo IDs, of the animal taken during short encounters at sea allows scientists and naturalists to assemble the pieces of a very large life-history puzzle one image at a time. Coordinated efforts have produced photographic catalogues for many marine mammal species including sperm, right, blue, and humpback whales, to name a few.

From the information in the ID catalogues, researchers can piece together an animal’s migrations and pattern of habitat use on scales from one day to a period of years. We can also use photo-ID data to estimate how many animals are in a given population, how long they live, how often they have calves, and who they prefer to hang out with.

February 19, 11:16 a.m -

Our photo-ID work here in the Kaikoura Canyon is focused on sperm whales. We are contributing to the sperm whale catalogue compiled by the Marine Mammal Research Group at University of Otago. As more and more photographed sightings of each catalogued individual are collected during a day, from day to day and even over months and years across many locations, the story of the lives of individual whales is developed into an epic tale--or, in the case of the sperm whale, an epic tail.

Photographing sperm whales is the epitome of hurry-up-and-wait. The researchers on the photo-ID boat track a whale’s movement underwater with a directional hydrophone for 30 minutes to an hour; the goal is to be within a few hundred meters of the whale when it announces its presence at the surface with a robust exhalation.

February 19, 12:18 p.m.

The vessel eases over to the now surface-resting whale, staying about 75 meters astern to be ready when the animal hoists its flukes and reveals the unique markings along the trailing edge of its tail. Photographers are positioned on the bow of the boat, at the ready with hefty cameras held at eye level (the favorite is a Nikon D3 with a 300mm lens). Now it is just a matter of firing off a series of shots as the whale lifts its flukes skyward to sound for another feeding dive. Squid and fish of the Kaikoura Canyon beware!

On the right are images of a whale we’ve already seen multiple times on this trip. The nicks and notches on the fluke make it very distinctive. With each photographed sighting, we collect time, position (in latitude and longitude), as well as dive and surface intervals. At the end of Day 2 we had three sightings of the same whale, which gives us and idea of its movements and an its preferred habitat. Two days later we identified it again, still hanging out in the same area.

February 19, 3:01 p.m.

The fun part begins once we are back at our computers, where we can compare the images from the day to the ones in the sperm whale catalogue to search for a match. This time, we checked our email first and it turns out that the image of the sperm whale dorsal fin posted in our second blog entry has already been recognized by the experienced eyes at Whale Watch Kaikoura as a whale known as Tutu. Sure enough, Tutu is also in the University of Otago sperm whale catalogue, but with the slightly less prosaic name of HL160. Looking back through our records tells us that HL160 has been seen at Kaikoura regularly since 1991—a true local!

February 21, 9:13 a.m.

The more photos, the merrier the knowledge. The sperm whales of New Zealand have let us learn a lot about their personal histories, and the longer the photo-ID project goes on, the more powerful that resource become.

All images on this page by Will Rayment, University of Otago.

A bad day fishing is better than a good day at work

But what happens when you are working, and fishing for data, and you have a really bad day. You talk to your team and look for the good news. That sums up today pretty well.

Dtag being attached. Ideally it releases later. (Luis Lamar,
Advanced Imaging & Visualization Lab, WHOI)

Wednesday night we attached a Dtag to a sperm whale at 19:30 local. It was programmed to release at 22:30. We heard the VHF beep on the tracking system occasionally through the night, when it was supposed to be steadily beeping at the surface waiting for us to pick it up. We slowly realized that the tag was still diving with the whale and returning to the surface about every hour, but its location on the animal meant that it could not transmit well, as it was mostly submerged even when the animal surfaced to breathe.

The result was a long and utterly sleepless night. Nevertheless, this morning our indefatigable tracking crew was out listening and watching and managed to relocate the animal. Indeed, the tag was still on where we had left it. The release mechanism must have failed. These tags are expensive—and priceless to us while we're out here. We have to recover it. That is the status of the tagging effort.

Archie taking off on his first (and hopefully not last)
science mission. (Luis Lamar)

But there is still more bad news, though with some serious silver linings. Archie, the aerial camera system, had a tough time today, as well. It was a calm day, so we launched Archie and, for the first time, it flew from the ship to a position over a whale and took some photographs. On his way back, he got a bit lost in the haze, and pilot Don had to hit the "come home" button to tell Archie to return to the helideck. Trouble was that Archie was programmed to return to where the helideck was when he was launched. The ship had moved since then.

Archie did what he was told, but his target was gone and he went for a swim. Happily, he was right where he was supposed to be, patiently waiting to be picked up, albeit upside down in the water.

Sperm whale from the air (Don LeRoi, Aerial Imaging Solutions,
and Wayne Perryman, SWFSC, NMFS)

In talking with Don and Wayne about this they can see nothing but positives:
1) We measured a sperm whale from a radio-controlled device at sea for the first time.
2) Archie passed his first-ever swim test.
3) Archie needs a homing beacon.
4) In a long career, this was Don's first ever crash.

Archie is now disassembled and drying out in the lab in pieces, doubtless an older, saltier, and wiser bird. Don and Wayne are bizarrely happy—it is as if their protégé went out into the big, bad world and got beat up, but came back with data and a pile of lessons learned.

All the while, the crew of the good ship Alucia remain endlessly patient and supportive as we stumble our way through our research plan.