Wrapping Up

This is the final blog posting for this expedition. We were back out in the canyon this morning with a whale that let us get some more good FLIR images. But with a forecast for 30 knots out of the south we decided not to deploy a Dtag because, if we had to leave the area without retrieving it, we would not be very welcome back in Woods Hole.

Male orca (Will Rayment, University of Otago)

On the way in we were treated to a busy group of Orcas all around the ship and some dusky dolphins foraging on a bait ball. Of course, the forecast turned out to be utterly wrong, but if we had got a tag on a whale, no doubt it would have turned ugly. This evening we shared photos and video with the crew, and tomorrow we will be on to the next chapter.

Cruise track and whale sightings.
(Will Rayment, University of Otago)

Here is the cruise by the numbers:
·  We had a total of 75 photo-ID encounters. The map shows our sightings and track line. Each day is a different color. High quality fluke photos were obtained on 51 occasions, representing 15 individuals. We encountered each animal between one and eight times.
·  The listening vessel ran a total of 367 nautical miles.
·  We also acquired a total of 35 hours of Dtag data from 7 tags. The deepest dive we recorded was 1,439 meters.
·  We acquired nine skin samples, FLIR data from three animals, and aerial camera images of two.

Thus, we did well with the photo-IDs, skin samples and Dtags, while the more developmental aspects of the project—aerial camera imagery and breath sampling—we brought a long way down the road. In summary, we all worked very hard, had a grand time, and have added to the knowledge base of how sperm whales use the Kaikoura Canyon.

We also saw some amazing wildlife: sperm whales, dusky and Hector's dolphins, albatross, petrels, shearwaters and much more.

This blog would not be complete without a huge thank you to the owner and crew of the Alucia for their support and patience throughout the cruise, and to many colleagues at Woods Hole Oceanographic Institution. We would also like to sincerely thank the whale watch community of Kaikoura for their advice and support in planning and undertaking this cruise. There are also a significant number of folks in various parts of the New Zealand Government that have made permitting of our work possible. As Chief Scientist on the cruise I would also like to thank Andreas, Don, Julie, Leigh, Liz, Luis, Marta, Maryann, Micah, Moe, Wayne and Will for their endless hard work and goodwill

Michael Moore

FLIR

There’s a member of our team that's a bit shy. She’s stayed on board when the seas have been choppy, and she’s rarely seen outside of her pelican case. Her name is FLIR. She hates to get wet. In fact she can't get wet. Otherwise, her parents get very upset.

FLIR is an infrared camera that we have set up to record infrared video. Using FLIR, we can see a sperm whale’s blow more clearly than with the naked eye, which is affected by wind, humidity, and air temperature.

Julie van der Hoop using FLIR. (Maryann Keith,
Advanced Imaging & Visualization Lab, WHOI

The idea is to use FLIR’s video to determine how fast a whale exhales. From there, we can figure out the amount gas that the whale has exhaled. This volume of inhaled and exhaled air, also known as the tidal volume, is a very important parameter for estimating metabolism, and is currently unknown for free-ranging large whales.

Tidal volume is only a fraction of lung capacity. An adult human male has a lung capacity of around six liters, but tidal volume is on the order of 500 milliliters. This means that, although we have the ability to exchange a lot of respiratory gases (oxygen and carbon dioxide) in a single breath, we typically move much less. Knowing how much oxygen and carbon dioxide is exchanged with every breath is a missing parameter when it comes to understanding marine mammal diving physiology.

The breathalyzer system that our research team has developed is another way to measure tidal volume by directly measuring the exhaled flow. Although the breathalyzer requires very animals to cooperate with our hand-pole approach, we can use FLIR from a distance and can calibrate it yield similar results. It’s our hope that one of these approaches will help us better understand the physiology that allows these animals to dive to such great depths for extended periods, time after time.

We are very grateful to our colleagues Ann Pabst and William McLellan at University North Carolina Wilmington for the loan of FLIR.

FLIR image of a cooperative sperm whale. (Maryann Keith,
Advanced Imaging & Visualization Lab, WHOI

On March 5 FLIR took center stage when an obliging sperm whale surfaced close to the Zodiac. We were able to shut down the outboard and sit and watch in awe as this monstrous male sperm whale slowly passed us by just a few feet away, while Julie acquired a series of infrared images of the blow using FLIR. The whale must have seen the boat but it never flinched, it just slowly pushed along the surface, blowing hard to restore its oxygen debt before fluking up to head down back to the bottom of the canyon for another hour of foraging.

A look back

We poked our nose out beyond the Kaikoura Peninsula but it was far too windy to do fieldwork today. Plenty of paperwork needed to be done though, mainly processing the data from the last few days of fieldwork.

We saw lots of whales on Saturday. Will Rayment and Liz Slooten were tracking whales and doing photo-ID. The WHOI team tagged two whales and flew the hexacopter above the whales to get measurements of their body condition. We retrieved our last tag was after midnight. A really productive day!

HL.160 "Tutu" showing his fluke.
(Will Rayment, University of Otago)

We are already starting to analyze the data, and over the next few months will be very interested to find out how data from this field trip compare to the long-term Kaikoura dataset. In 1990, Liz Slooten and Steve Dawson from the University of Otago started a research project on sperm whales in Kaikoura, using photo-ID, sound recordings, and behavioral observations. Graduate students and post-docs who joined the project include Nathalie Jaquet, who studied seasonal changes in the distribution and behavior of the whales. Caron Chessum, Simon Childerhouse, and Miranda van der Linde determined that the number of whales in the Kaikoura area has declined significantly from almost 100 individuals in 1991 to about 50 individuals now. (We are not yet sure if this means a shift in their distribution, with fewer whales coming close to shore, or an actual decline in the population.) Christoph Richter carried out detailed studies on the effects of tourism on sperm whales. Olaf Jaeke and Lesley Douglas studied sperm whale sounds, and Abe Growcott and Quin Rhinelander used the whales’ sounds to estimate their size. Brian Miller used a hydrophone array to follow the whales underwater. The University of Otago team also built directional hydrophones and hydrophone arrays for finding whales, and a stereo-camera system to measure whales.

Dusky dolphin at play. (Will Rayment, University of Otago)

Background data from the long-term study provide the context for the joint WHOI–University of Otago project. For example, one of the whales we tagged on this trip, known as Tutu or HL.160, was first seen in 1991 and has been seen 127 times since then. This is clearly a mature male. Another whale seen on this field trip, LNL.160, has been seen 180 times since 1994. Repeated estimates of this whale, using the stereo-photography and acoustic length measurements show that it has grown from 14.6 meters to 15.1 meters. These data on age and growth will be very useful in interpreting the information gathered on this field trip.

Hector's dolphins. (Leigh Hickmott, Open Ocean
Consulting/University of St. Andrews)

If the data on diving behavior we get from the DTAGS turn out to be similar to the data from the hydrophone arrays, then information from the two methods can be combined to provide insight into the diving behavior of sperm whales. On the other hand, if the results are different this will lead to further questions about whether the differences are due to the different techniques, differences between the individual whales in the two data sets, differences in the locations, changes in oceanographic conditions this year compared to earlier years, or a combination of the above.

To provide a break from the database work today, we did some research on two of the sperm whales’ smaller cousins. We spotted some Hector’s dolphins and dusky dolphins in the calm water on the north side of the peninsula. The dusky dolphins were doing their usual leaping and bounding. The Hector’s dolphins were much less boisterous, but very approachable and curious. Two of the Hector’s dolphins had joined a group of dusky dolphins, which is unusual. We took photographs that will be added to long-term photo-ID catalogs for these two species.

You are what you eat

Beneath the beauty of the animal kingdom there is a fierce world, in which you are either hunting or you are dinner. Life is a constant struggle for survival, and finding food is essential to existence. That is why one of the most important questions in the study of wild animals is: "What do they eat?."

A wandering albatross wandering in search of a meal.
(Will Rayment, University of Otago)

In the ocean, the quest for food often requires going far or deep. Some animals travel hundreds of miles over the ocean just to find a meal. Such is the case of the wandering albatross, a magnificent seabird that we often see off the coast of Kaikoura. Satellite tracking of wandering albatross has revealed that they can cover up to 15,000 km from their nest on a single foraging trip, flying day and night at speeds of up to 80 km per hour (50 mph).

Almost everything about sperm whales is superlative: they are the largest of the odontocetes (toothed whale), the deepest diving cetacean, and their echolocation clicks are the loudest underwater sound produced by any animal. Their biology and physiology are fine products of thousands of years of evolution which allow them to go as deep as 2,500 meters (1.5 miles) and as long as two hours to locate their prey.

To date, there has been just one analysis of the diet of sperm whales in New Zealand. The study revealed that sperm whales eat squid and a relatively high proportion of bottom-living fish. This is intriguingly distinct from sperm whale populations elsewhere, which eat almost exclusively squid. Understanding the diet of these animals allows scientists to identify their role in the ecosystem and provides a better understanding of their distribution and habitat use. In turn, this information is very valuable for conservation management.

But how do we find out what these animals eat if they spend most of their time at great depths underwater and don’t feed at the surface? The answer can be provided by the analysis of stable isotope signatures from whale skin. Studying stable isotopes is a non-invasive method that can provide information on diet as well as physiology and ecotoxicology.

Collecting sperm whale skin from a DTAG.
(Wayne Perryman, SWFSC, NOAA)

Isotopes are variants of a particular chemical element, and stable isotopes are those variants that remain stable over time. The stable isotope composition (say, for carbon and nitrogen) in an animal is largely determined by the isotopic composition of the food, water, and gas that the animal takes in. These elements are eventually used for making new soft tissue (like skin) and biological minerals. Through the analysis of the composition of stable isotopes, researchers can track down the primary source of the animals’ diet by matching those isotope signatures of the skin to the ones of potential prey species.

Getting our hands on samples of whale skin is a tale of persistence and patience. Every time a sperm whale dives, there’s a chance that small strips of sloughed skin will remain at the surface. We only have to keep our eyes open for those skin fragments in the slick left by a fluking whale, have a net at hand, scoop it up, and put it in the freezer. We also often find small pieces of skin trapped in the suction cups of DTAGs. Later on, stable isotope analysis can be carried out back at the laboratory.

During the expedition we have so far collected nine skin samples. They are happily frozen and waiting to be analysed—ahopefully to reveal a little more about the diet of sperm whales and what makes Kaikoura such a productive foraging ground.  

Further reading on stable isotope analysis: 
Newsome, S.D, Clementz, M.T., and Koch, P.L., "Using stable isotope biogeochemistry to study marine mammal ecology," Marine Mammal Science 26 (2010): 509-572.

Whales, whales and more whales

Today dawned grey and cold.

Liz Slooten (crouching) listens for whales. (Maryann Morin,
Advanced Imaging and Visualization Lab, WHOI)

We started looking for whales to the southwest of where we have been working recently. We were interested in a tongue of the canyon that looped northeast, with a nice loop around the 1,000-meter contour, but there was nothing to be seen or heard, so we headed back offshore and went northeast to an area where we had been finding whales earlier in the cruise. Before we knew it we were spoiled for choice.

Tag on! (Will Rayment, University of Otago)

Andreas and Micah piled into the kayak, along with their gas sampling gear and breathalyser funnel system, and off they paddled. A pair of sperm whales sensed them coming, turned and proceeded to do a number of spyhops. It seemed as this if they were curious about this hitherto unseen contraption that had arrived in their patch of ocean. Indeed, the kayak and the spyhopping whales came very close to each other, but unfortunately a spyhop does not include a breath, so their breath remained unsampled. However, Julie van der Hoop was finally able to get some infrared imagery of sperm whale blows, something we have been waiting to do until the conditions were calm enough to avoid any water on the camera.

We then managed to get a couple of tags deployed later in the afternoon over the space of half an hour. Meanwhile, Archie the aerial camera was feeling confident after yesterday's trials ashore, so Don and Wayne did some trials around the ship. When an opportunity arose, Archie sallied forth over a tagged
whale and acquired good aerial images before returning
safely home. To be able to do this in a rolling swell is a
huge accomplishment. Don and Wayne have worked
through the many challenges they have faced and come
up smiling.

Archie's view of a tagged whale.
(Don Leroi, Aerial Imaging Solutions and
Wayne Perryman, SWFSC, NOAA)

It is wonderful to have Liz Slooten from the University of Otago and the New Zealand Whale and Dolphin Trust aboard now, with her extensive knowledge of these animals, the area, and acoustic tracking. We miss Luis lamar, but in his stead we have Maryann Morin, also from the Advanced Imaging and Visualization Lab at WHOI. So welcome aboard to Liz and Maryann.

Waiting for weather and Archie reincarnated

We woke to a stiff southerly breeze this morning. New parts for Archie, the aerial camera, have been installed, so Don and Wayne went ashore to look for a sheltered spot for his first flight after his dunking. We then headed offshore and heard and saw a whale, but the swells were steep and lively, so we retreated. Archie went ashore for more exercise. The forecast for tomorrow is good.

We were sad to say goodbye today to Luis Lamar, photographer extraordinaire, and Marta Guerra, whale tracker, tag-in-the-water spotter, and all-round great colleague.

Aerial Camera Update 

Bubby and Bubby. (Moira Brown, New England Aquarium)

Changes in the reproductive and nutritive condition of large cetaceans are reflected in changes to their shape. These changes can be very accurately measured from overhead aerial photographs, which provide insight into how both long- and short-term changes in the environment and other, human-related factors impact populations.

This field of research began with photographic missions conducted from manned platforms (airplanes, helicopters) but new developments in imaging systems and unmanned aerial technologies are providing an opportunity to take this kind of sampling into situations where it wasn’t available previously or was prohibitively expensive.

Bubby takes flight. (Moira Brown, New England Aquarium)

We have had success using measurements from vertical images to track changes in the condition of North Atlantic right whales and eastern North Pacific gray whales. What we are learning is that the location in which a whale stores nutritive capital (mainly fat) varies among species. Moreover, to efficiently monitor changes in condition over time, we first need to look carefully at the shape of several individuals within a population to identify the parts of the body that appear to show the most variability in the relationship between length and width of the animals. Our study is the first step in that process.

Don and Wayne adjust the gyros on Bubby's stabilized
platform. (Moira Brown, New England Aquarium)

While waiting for a part to repair Archie after his unscheduled flotation test last week, the team completed construction of a small quadrocopter that has a water-tight hull and seems like an ideal solution to the challenge of working from the small boat to approach the sperm whales. The new aircraft, named Bubby after a young member of the deck crew, flew beautifully and we found that we could time the motion of the small boat to the point that we could calibrate Bubby’s gyros under calm conditions.

Launching Bubby from the boat was relatively simple and safe, but catching him on his return to a very lively platform turned out to be a harrowing experience. The primary problem we faced was that the momentum of the boat’s movements were transferred through the pilot’s fingers to the sticks of the flight controller, making it very difficult to safely maneuver the aircraft into the hands of the "catcher." For that person, it was like trying to handle a wild pitch from a knuckleballer. The next iteration of Bubby will be designed to splash down beside the small boat so that we can simply retrieve him with a net.

In the meantime, we have Archie, our hexacopter, back up and running. So our plan now is to go back to our original approach of maneuvering a bit closer to the whales and launching Archie from the ship's helicopter deck. Now we just need a break in the weather to get back to work.

Why Kaikoura?

Today there were monster swells in the ocean above the Kaikoura Canyon, and when the wind started to blow hard, we spent the day at anchor southwest of Kaikoura Peninsula taking stock, looking at data, and generally gathering our wits about us.

So, why have we decided to do this work off the Kaikoura coast and not someplace more convenient to Woods Hole? There are very few places in the world where sperm whales can be reliably found close to shore. Kaikoura is one of them. The feature that makes the location so special is the Kaikoura Canyon—an undersea trench that cuts through the continental shelf such that the seabed plunges to depths over 1000 metres within 4 kilometres of the coastline.

A sperm whale heads for the deep waters of the Kaikoura
Canyon to feed. (Will Rayment, University of Otago)

Whales aren't the only marine mammal attracted to the food
supplied by the riches of the canyon. Here, a New Zealand
fur seal. (Will Rayment, University of Otago)

The biological productivity within the canyon is enormous. Scientists have recently revealed that the biomass of seabed-dwelling invertebrates in the Kaikoura Canyon is 100 times greater than in typical deep-sea habitats. Likewise, the densities of bottom-living fish are dramatically higher in the canyon than on the surrounding seafloor.

This presumably makes the Kaikoura canyon a great place to look for food. And sperm whales need a lot of food. They are the largest of the odontocetes, the toothed whales, and probably require up to 1.5 tons of food per day. As we have seen from our DTAG data, they routinely dive to over 1,000 meters looking for their prey, primarily squid and bottom-living fish. Exactly what they eat at Kaikoura remains to be seen and is something we hope to learn from our analyses of their sloughed skin and fecal samples.

But it’s not just sperm whales that make use of the abundant food supply at Kaikoura—a there is a plethora of other marine mammal species that exploit this rich submarine larder, as well. Kaikoura is home to large numbers of dusky dolphins, which can be seen playing and resting in the coastal waters during the daytime before heading offshore to feed at night. Similarly, New Zealand fur seals rest up and bask on the rocky coastline, then swim out over the deep canyon waters to forage. There are a number of more transient visitors, too. So far, during our brief visit we have seen southern right, blue, and killer whales. And the productive waters are a Mecca for seabirds. Every day we are surrounded by albatrosses, petrels, and shearwaters, all looking for a piece of the action.

Seabirds like this Buller's albatross are attracted by the
productivity of the canyon--and the antics of scientists.
(Will Rayment, University of Otago)

The abundance and diversity of marine life makes Kaikoura a great place for scientists to work. Similarly, it’s a big draw for human visitors, and there is now a thriving tourism industry in Kaikoura. People come from far and wide to go whale watching, swim with dolphins, and view the huge variety of seabird species. During our time here we have come to realize just how lucky we are to do what we do in such a special environment.

Further reading:
De Leo et al., "Submarine canyons: Hotspots of benthic biomass and productivity in the deep sea," Proceedings of the Royal Society B 277(2010): 2783-2792.