Finding the edge: Preliminary insights into blue whale habitat selection in New Zealand

By Dawn Barlow, MSc student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

I was fortunate enough to spend the Austral summer in the field, and so while the winter rain poured down on Oregon I found myself on the water with the sun and wind on my face, looking for blue whales in New Zealand. This spring I switched gears and spent time taking courses to build my analytical toolbox. In a course on technical writing and communication, I was challenged to present my research using only pictures and words with no written text, and to succinctly summarize the importance of my research in an introduction to a technical paper. I attended weekly seminars to learn about the diverse array of marine science being conducted at Oregon State University and beyond. I also took a course entitled “Advanced Spatial Statistics and Geographic Information Science”. In this skill-building course, we were given the opportunity to work with our own data. Even though my primary objective was to expand the tools in my toolbox, I was excited to explore preliminary results and possible insight into blue whale habitat selection in my study area, the South Taranaki Bight region (STB) of New Zealand (Figure 1).

Figure 1. A map of New Zealand, with the South Taranaki Bight (STB) region delineated by the black box. Farewell Spit is denoted by a star, and Kahurangi point is denoted by an X.

Despite the recent documentation of a foraging ground in the STB, blue whale distribution remains poorly understood in New Zealand. The STB is New Zealand’s most industrially active marine region, and the site of active oil and gas extraction and exploration, busy shipping traffic, and proposed seabed mining. This potential space-use conflict between endangered whales and industry warrants further investigation into the spatial and temporal extent of blue whale habitat in the region. One of my research objectives is to investigate the relationship between blue whales and their environment, and ultimately to build a model that can predict blue whale presence based on physical and biological oceanographic features. For this spring term, the question I asked was:

Is the number of blue whales present in an area correlated with remotely-sensed sea surface temperature and chlorophyll-a concentration?

For the purposes of this exploration, I used data from our 2017 survey of the STB. This meant importing our ship’s track and our blue whale sighting locations into ArcGIS, so that the data went from looking like this:

… to this:

The next step was to get remote-sensed images for sea surface temperature (SST) and chlorophyll-a (chl-a) concentration. I downloaded monthly averages from the NASA Moderate Resolution Imaging Spectrometer (MODIS aqua) website for the month of February 2017 at 4 km2 resolution, when our survey took place. Now, my images looked something more like this:

But, I can’t say anything reliable about the relationships between blue whales and their environment in the places we did not survey.  So next I extracted just the portions of my remote-sensed images where we conducted survey effort. Now my maps looked more like this one:

The above map shows SST along our ship’s track, and the locations where we found whales. Just looking at this plot, it seems like the blue whales were observed in both warmer and colder waters, not exclusively in one or the other. There is a productive plume of cold, upwelled water in the STB that is generated off of Kahurangi point and curves around Farewell Spit and into the bight (Figure 1). Most of the whales we saw appear to be near that plume. But how can I find the edges of this upwelled plume? Well, I can look at the amount of change in SST and chl-a across a spatial area. The places where warm and cold water meet can be found by assessing the amount of variability—the standard deviation—in the temperature of the water. In ArcGIS, I calculated the deviation in SST and chl-a concentration across the surrounding 20 km2 for each 4 km2 cell.

Now, how do I tie all of these qualitative visual assessments together to produce a quantitative result? With a statistical model! This next step gives me the opportunity to flex some other analytical muscles, and practice using another computational tool: R. I used a generalized additive model (GAM) to investigate the relationships between the number of blue whales observed in each 4 km2 cell our ship surveyed and the remote-sensed variables. The model can be written like this:

Number of blue whales ~ SST + chl-a + sd(SST) + sd(chl-a)

In other words, are SST, chl-a concentration, deviation in SST, and deviation in chl-a concentration correlated with the number of blue whales observed within each 4 km2 cell on my map?

This model found that the most important predictor was the deviation in SST. In other words, these New Zealand blue whales may be seeking the edges of the upwelling plume, honing in on places where warm and cold water meet. Thinking back on the time I spent in the field, we often saw feeding blue whales diving along lines of mixing water masses where the water column was filled with aggregations of krill, blue whale prey. Studies of marine mammals in other parts of the world have also found that eddies and oceanic fronts—edges between warm and cold water masses—are important habitat features where productivity is increased due to mixing of water masses. The same may be true for these New Zealand blue whales.

These preliminary findings emphasize the benefit of having both presence and absence data. The analysis I have presented here is certainly strengthened by having environmental measurements for locations where we did not see whales. This is comforting, considering the feelings of impatience generated by days on the water spent like this with no whales to be seen:

Moving forward, I will include the blue whale sighting data from our 2014 and 2016 surveys as well. As I think about what would make this model more robust, it would be interesting to see if the patterns become clearer when I incorporate behavior into the model—if I look at whales that are foraging and traveling separately, are the results different? I hope to explore the importance of the upwelling plume in more detail—does the distance from the edge of the upwelling plume matter? And finally, I want to adjust the spatial and temporal scales of my analysis—do patterns shift or become clearer if I don’t use monthly averages, or if I change the grid cell sizes on my maps?

I feel more confident in my growing toolbox, and look forward to improving this model in the coming months! Stay tuned.

New aerial footage captures blue whale lunge feeding!

By Dawn Barlow, MSc student, OSU Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

This past field season the New Zealand blue whale team was lucky enough to capture something spectacular – an aerial view of a blue whale surface lunge feeding. I invite you to view the footage and listen to Leigh’s narration of the event in the video below!

Below is the full press release, written by Mark Floyd:

NEWPORT, Ore. – Blue whales didn’t become the largest animals ever to live on Earth by being dainty eaters and new video captured by scientists at Oregon State University shows just how they pick and choose their meals.

There is a reason for their discretion, researchers say. The whales are so massive – sometimes growing to the length of three school buses – that they must carefully balance the energy gained through their food intake with the energetic costs of feeding.

“Modeling studies of blue whales ‘lunge-feeding’ theorize that they will not put energy into feeding on low-reward prey patches,” said Leigh Torres, a principal investigator with the Marine Mammal Institute at Oregon State, who led the expedition studying the blue whales. “Our footage shows this theory in action. We can see the whale making choices, which is really extraordinary because aerial observations of blue whales feeding on krill are rare.”

“The whale bypasses certain krill patches – presumably because the nutritional payoff isn’t sufficient – and targets other krill patches that are more lucrative. We think this is because blue whales are so big, and stopping to lunge-feed and then speeding up again is so energy-intensive, that they try to maximize their effort.”

The video, captured in the Southern Ocean off New Zealand, shows a blue whale cruising toward a large mass of krill – roughly the size of the whale itself. The animal then turns on its side, orients toward the beginning of the krill swarm, and proceeds along its axis through the entire patch, devouring nearly the entire krill mass.

In another vignette, the same whale approaches a smaller mass of krill, which lies more perpendicular to its approach, and blasts through it without feeding.

“We had theorized that blue whales make choices like this and the video makes it clear that they do use such a strategy,” explained Torres, who works out of Oregon State’s Hatfield Marine Science Center in Newport, Oregon. “It certainly appears that the whale determined that amount of krill to be gained, and the effort it would take to consume the meal wasn’t worth the effort of slowing down.

“It would be like me driving a car and braking every 100 yards, then accelerating again. Whales need to be choosy about when to apply the brakes to feed on a patch of krill.”

The researchers analyzed the whale’s lunge-feeding and found that it approached the krill patch at about 6.7 miles per hour. The act of opening its enormous mouth to feed slowed the whale down to 1.1 mph – and getting that big body back up to cruising speed again requires a lot of energy.

The rare footage was possible through the use of small drones. The OSU team is trained to fly them over whales and was able to view blue whales from a unique perspective.

“It’s hard to get good footage from a ship,” Torres said, “and planes or helicopters can be invasive because of their noise. The drone allows us to get new angles on the whales without bothering them.”

What it looks like when science meets management decisions

Dr. Leigh Torres
GEMM Lab, OSU, Marine Mammal Institute

It’s often difficult to directly see the application of our research to environmental management decisions. This was not the case for me as I stepped off our research vessel Tuesday morning in Wellington and almost directly (after pausing for a flat white) walked into an environmental court hearing regarding a permit application for iron sands mining in the South Taranaki Bight (STB) of New Zealand (Fig. 1). The previous Thursday, while we surveyed the STB for blue whales, I received a summons from the NZ Environmental Protection Authority (EPA) to appear as an expert witness regarding blue whales in NZ and the potential impacts of the proposed mining activity by Trans-Tasman Resources Ltd. (TTR) on the whales. As I sat down in front of the four members of the EPA Decision Making Committee, with lawyers for and against the mining activity sitting behind me, I was not as prepared as I would have liked – no business clothes, no powerpoint presentation, no practiced summary of evidence. But, I did have new information, fresh perspective, and the best available knowledge of blue whales in NZ. I was there to fill knowledge gaps, and I could do that.

Figure 1. Distribution map of blue whale sightings (through Nov 2016) in the South Taranaki Bight (STB) of New Zealand, color-coded by month. Also identified are the current locations of oil and gas platforms (black flags) and the proposed area for seabed mining (yellow polygon). The green stars denote the location of our hydrophones within the STB that record blue whale vocalizations. The source of the upwelling plume at Kahurangi Point, on the NW tip of the South Island, is also identified.

For over an hour I was questioned on many topics. Here are a few snippets:

Why should the noise impacts from the proposed iron sands mining operation on blue whales be considered when seismic survey activity produces noise 1,000 to 100,000 times louder?

My answer: Seismic survey noise is very loud, but it’s important to note that seismic and mining noises are two different types of sound sources. Seismic surveys noise is an impulsive noise (a loud bang every ~8 seconds), while the mining operation will produce non-impulsive (continuous) sound. Also, the mining operation will likely be continuous for 32 years. Therefore, these two sound sources are hard to compare. It’s like comparing the impacts of listening to pile driving for a month, and listening to a vacuum cleaner for 32 years. What’s important here is to considering the cumulative effects of both these noise sources occurring at the same time: pile driving on top of vacuum cleaner.

 

How many blue whales have been sighted within 50 km of the proposed mining site?

My answer: Survey effort in the STB has been very skewed because most marine mammal sighting records have come from marine mammal observers aboard seismic survey vessels that primarily work in the western regions of the STB, while the proposed mining site is in the eastern region. So at first glance at a distribution map of blue whale sightings (Fig. 1) we may think that most of the blue whales are found in the western region of the STB, but this is incorrect because we have not accounted for survey effort.

During our past three surveys in the STB we have surveyed closer to the proposed mining site. In 2014 our closest point of survey approach to the mining site was 26 km, and our closest sighting was 63 km away. In 2016, we found no whales north of 40’ 30” in the STB and the closest sighting was 107 km away from the proposed mining site, but this was a different oceanographic year due to El Niño conditions. During this recent survey in 2017, our closest point of survey approach to the proposed mining site was 22 km, and our closest sighting was 29 km, with a total of 9 sightings of 16 blue whales within 50 km of the proposed mining site. With all reported sighting records of blue whales tabulated, there have been 16 sightings of 33 blue whales within 50 km of the proposed mining site. Considering the minimal survey effort in this region, this is actually a relatively high number of blue whale sighting records near the proposed mining site.

Additionally, we have a hydrophone located 18.8 km from the proposed mining site. We have only analyzed the data from January through June 2016 so far, but during this period we have an 89% daily detection rate of blue whale calls.

 

Why are blue whales in the STB and where else are they found in NZ?

My answer: A  wind-driven upwelling system occurs off Kahurangi Point (Fig. 1) along the NW coast of the South Island. This upwelling brings nutrient rich deep water to the surface where it meets the sunlight causing primary productivity to begin. Currents push these productive plumes of water into the STB and zooplankton, such as krill that is the main prey item of blue whales, aggregate in these productive areas to feed on the phytoplankton. Blue whales spend time in the STB because they depend on the predictability of these large krill aggregations in the STB to feed efficiently.

Sightings of blue whales have been reported in other areas around New Zealand, but nowhere with regular frequency or abundance. There may be other areas where blue whales feed occasionally or regularly in New Zealand waters, but these areas have not been documented yet. We don’t know very much about these newly documented New Zealand blue whales, yet what we do know is that the STB is an important foraging area for these animals.

 

Questions like these went on and on, and I was probed with many insightful questions. Yet, the question that sticks with me now was asked by the Chair of the Decision Making Committee regarding the last sentence in my submitted evidence where I remarked on the importance of recognizing the innate right of animals to live in their habitat without disturbance. “This sounds like an absolute statement,” claimed the Chair, “like no level of disturbance is tolerable”. I was surprised by the Chair’s focus on this statement over others. I reiterated my opinion that we, as a society, need to recognize the right of all animals to live in undisturbed habitats whenever we consider any new human activity. “That’s why we are all here today”, I explained to the committee, “to recognize and evaluate the potential impacts of TTR’s proposed mining operation on blue whales, and other animals, in the STB”. Undisturbed habitat may not always be achievable, but when we make value-based decisions regarding permitting industrial projects we need to recognize biodiversity’s right to live in uncompromised environments.

I do not envy this Decision Making Committee, as over three weeks they are hearing evidence from all sides on a multitude of topics from environmental, to economic, to cultural impacts of the proposed mining operation. They will be left with the very hard task of balancing all this information and deciding to approve or decline the mining permit, which would be a first in NZ and may open the floodgates of seabed mining in the country. My only hope is that our research on blue whales in NZ over the last five years has filled knowledge gaps, allowing the Decision Making Committee to fully appreciate the importance of the STB habitat to NZ blue whales, and appropriately consider the potential impacts of TTR’s proposed mining activities on this unique population.

A blue whale surfaces in a calm sea in the South Taranaki Bight of New Zealand (Photo L. Torres).

A day in the office

Join us for a couple boat rides as we study blue whales in the South Taranaki Bight of New Zealand.

In both videos below you can see and hear the field team coordinate to capture photo-identification images of the whale(s) while also obtaining a small tissue biopsy sample. It is important to match the individual whale to the sample so we can link biological data obtained from the sample (genetics, hormones, stable isotopes) to the individual whale. We also carefully take notes on where, when and what we collect in order to help us keep track of our data.

In this video clip you can watch as we gently approach two blues surfacing off the starboard bow of the RV Star Keys in order to capture photo-identification images and a small tissue biopsy sample. Callum Lilley (DOC) on the bow; Leigh Torres, Dawn Barlow, and Todd Chandler (OSU) photographing and coordinating from the flying bridge.

 

We are in the small boat here collecting data on a pair of blue whales. Callum Lilley (DOC) is on the rifle; Leigh Torres (OSU) is on the camera and taking notes; Todd Chandler (OSU) is on the helm.

 

Keeping up with blue whales in a dynamic environment

By Dawn Barlow, MSc student, Department of Fisheries and Wildlife, Geospatial Ecology of Marine Megafauna Lab

“The marine environment is patchy and dynamic”. This is a phrase I have heard, read, and written repeatedly in my studies of marine ecology, and it has become increasingly tangible during the past several weeks of fieldwork. The presence of the blue whales we’ve come here to study is the culmination of a chain of events that begins with the wind. As we huddle up at anchor or in port while the winds blow through the South Taranaki Bight, the water gets mixed and our satellite images show blooms of little phytoplankton lifeforms. These little phytoplankton provide food for the krill, the main prey item of far larger animals—blue whales. And in this dynamic environment, nothing stays the same for long. As the winds change, aggregations of phytoplankton, krill and whales shift.

When you spend hours and hours scanning for blue whales, you also grow intimately familiar with everything that could possibly look like a blue whale but is not. Teasers include whitecaps, little clouds on the horizon, albatrosses changing flight direction, streaks on your sunglasses, and floating logs. Let me tell you, if we came here to study logs we would have quite the comprehensive dataset! We have had a few days of long hours with good weather conditions and no whales, and it is difficult not to be frustrated at those times—we came here to find whales. But the whale-less days prompt musings of what drives blue whale distribution, foraging energetics, and dreams of elaborate future studies and analyses, along with a whole lot of wishing for whales. Because, let’s admit it, presence data is just more fun to collect.

The view from the flying bridge of R/V Star Keys of Mt. Taranaki and a calm sea with no whales in sight. Photo by D. Barlow.

But we’ve also had survey days filled with so many whales that I can barely keep track of all of them. When as soon as we begin to head in the direction of one whale, we spot three more in the immediate area. Excited shouts of “UP!! Two o’clock at 300 meters!” “What are your frame numbers for your right side photos?” “Let’s come 25 degrees to port” “UUUPPP!! Off the bow!” “POOOOOOP! Grab the net!!” fill the flying bridge as the team springs into action. We’ve now spotted 40 blue whales, collected 8 biopsy samples, 8 fecal samples, flown the drone over 9 whales, and taken 4,651 photographs. And we still have more survey days ahead of us!

A blue whale surfaces just off the bow of R/V Star Keys. Photo by D. Barlow.

In Leigh’s most recent blog post she described our multi-faceted fieldwork here in the South Taranaki Bight. Having a small inflatable skiff has allowed for close approaches to the whales for photo-identification and biopsy sample collection while our larger research vessel collects important oceanographic data concurrently. I’ve been reading numerous papers linking the distribution of large marine animals such as whales with oceanographic features such as fronts, temperature, and primary productivity. In one particular sighting, the R/V Star Keys idled in the midst of a group of ~13 blue whales, and I could see foamy lines on the surface where water masses met and mixed. The whales were diving deep—flukes the size of a mid-sized car gracefully lifting out of the water. I looked at the screen of the echosounder as it pinged away, bouncing off a dense layer of krill (blue whale prey) just above the seafloor at around 100 meters water depth.  As I took in the scene from the flying bridge, I could picture these big whales diving down to that krill layer and lunge feeding, gorging themselves in these cool, productive waters. It is all mostly speculative at this point and lots of data analysis time remains, but ideas are cultivated and validated when you experience your data firsthand.

A blue whale shows its fluke as it dives deep in an area with abundant krill deep in the water column. Photo by L. Torres.

The days filled with whales make the days without whales worthwhile and valuable. To emphasize the dynamic nature of the environment we study, when we returned to an area in which we had seen heaps of whales just 12 hours before, we only found glassy smooth water and no whales whatsoever. Changing our trajectory, we came across nothing for the first half of the day and then one pair of whales after another. Some traveling, some feeding, and two mother-calf pairs.

The dynamic nature of the marine environment and the high mobility of our study species is what makes this work challenging, frustrating, exciting, and fascinating. Now we’re ready to take advantage of our next weather window to continue our survey effort and build our ever-growing dataset. I relish the wind-swept, sunburnt days of scanning and musing, and I also look forward to settling down with all of these data to try my best to compile all of the pieces of this blue whale puzzle. And I know that when I find myself behind a computer screen processing and analyzing photos, survey effort, drone footage, and oceanographic data I will be imagining the blue waters of the South Taranaki Bight, the excitement of seeing the water glow brilliantly just before a whale surfaces off our bow, and whale-filled survey days that end only when the sun sets over the water.

A big moon rises to the east and a bright oil rig on the horizon at the end of a long and fruitful survey day. Photo by L. Torres.
And to the west of the moon and the rig, the sun sets over the South Taranaki Bight. Photo by L. Torres.

 

I love it when a plan comes together

By Dr. Leigh Torres

GEMM Lab

After four full-on days at sea covering 873 nautical miles, we are back in port as the winds begin to howl again and I now sip my coffee with a much appreciated still horizon. Our dedicated team worked the available weather windows hard and it paid off with more great absence data and excellent presence data too: blue whales, killer whales, common dolphins, and happily swimming pilot whales not headed to nearby Farewell Spit where a sad, massive stranding has occurred. It has been an exhausting, exhilarating, frustrating, exciting, and fulfilling time. As I reflect on all this work and reward, I can’t help but feel gratified for our persistent and focused planning that made it happen successfully. So, as we clean-up, organize data, process samples, and sit in port for a few days I would like to share some of our highlights over the past four days. I hope you enjoy them as much as we did.

The team in action on the RV Star Keys. Callum Lilley (DOC) on the bow waiting for a biopsy opportunity, Dawn Barlow (OSU) on the radio communicating with the small boat, Kristin Hodge (Cornell) taking photos of whales, Captain James Dalzell (Western Work Boats) on the helm, and Chief Engineer Spock (Western Work Boats) keeping his eyes peeled for a blow. (Photo credit: L. Torres)

 

In the small boat off looking for whales in a lovely flat, calm sea with an oil rig in the background. (Photo credit: D. Barlow)

 

Small boat action with Todd Chandler (OSU) at the helm, Leigh Torres (OSU) on the camera getting photo-id images, and Callum Lilley (DOC) taking the biopsy shot, and the dart is visible flying toward the whale in the black circle. (Photo credit: D. Barlow)

 

The stars of the show: blue whales. A photograph captured from the small boat of one animal fluking up to dive down as another whale surfaces close by. (Photo credit: L. Torres)

 

Collecting oceanographic data: Spock and Jason (Western Work Boats) deploy the CTD from the Star Keys. The CTD is an instrument that measures temperature, salinity, fluorescence and depth continuously as it descends to the bottom and back up again. (Photo credit: L. Torres)

 

The recently manufactured transducer pole in the water off the RV Star Keys (left) deployed with the echosounder to collect prey availability data, including this image (right) of krill swarms near feeding blue whales. (Photo credit: L. Torres)

 

The small boat returns to the Star Keys loaded with data and samples, including a large fecal sample in the net: The pooper scooper Leigh Torres (OSU), the biopsy rifle expert Callum Lilley (DOC), and the boat operator Todd Chandler (OSU). (Photo credit: D. Barlow)

 

Drone operator and videographer, Todd Chandler (OSU) under the towel (crucial piece of gear) to minimize glare on the screen as he locates and records blue whales. (Photo credit: K. Hodge)

 

A still shot captured from the drone footage of two adult blue whales surfacing in close proximity. (Photo credit: T. Chandler)

 

The team in action looking for blue whales in ideal survey conditions with Mt. Taranaki in the background. Todd Chandler (OSU) enters survey data while Dawn Barlow (OSU) spies for whale blows. (Photo credit: L. Torres)

 

A late evening at-sea after a big day sees Callum Lilley (DOC) processing a blue whale biopsy sample for transport, storage and analysis. (Photo credit: K. Hodge)

 

And we can’t forget why so many have put time, money and effort into this project: These blue whales are feeding and living within a space exploited by humans for multiple purposes, so we must ensure minimal impacts to these whales and their sustained health. (Photo credit: D. Barlow)

The worst summer ever!

By Dr. Leigh Torres

Geospatial Ecology of Marine Megafauna Lab

“This is the worst summer ever in New Zealand.” During our four days of prep in Wellington before heading off on our vessel, almost all my friends and colleagues I spoke to said this statement (often with added emphasis). It’s been cold and windy here all summer long, and when the weather has cleared it has brought only brief respite. These comments don’t bode well for our blue whale survey dependent on calm survey conditions, but February is typically the prime month for good weather in New Zealand so I’m holding out hope. And this unpredictable weather is the common denominator of all field work. Despite months (years?) of preparation, with minute attention to all sort of details (e.g., poop net handle length, bag size limits, length of deployment lines), one of the most important factors to success is something we have absolutely no control over: the weather.

After just one day on the water, I can see that the oceanographic conditions this year are nothing like the hot-water El Niño conditions we experienced last summer. Surface water temperatures today ranged between 12.8 and 13.6 ⁰C. These temps are 10 degrees (Celsius) cooler than the 22 ⁰C water we often surveyed last summer. 10 degrees! Additionally, the current windy conditions have stirred up the upper portion of the ocean water column causing the productive mixed layer to be much deeper (therefore larger) than last year. While Kiwis may complain about the ‘terrible’ weather this summer, the resulting cold and productive oceanographic conditions are likely preferable for the whales. But where are the whales and can we find them with all this wind?

Today we had a pocket of calm conditions so our dedicated research team and crew hit it with enthusiasm, and collected a whole lot of great absence data. “Absence data?” you may ask. Absence data is all the information about where the whales are not, and is just as important as presence data (information about where the whales are) because it’s the comparison between the two sets of data (Presence vs Absence) that allows us to describe an animal’s “habitat use patterns”. Today we surveyed a small portion of the South Taranaki Bight for blue whales for about 6 hours, but the only blue animals we saw were little blue penguins and a blue shark (plus fur seals, dolphins, albatrosses, shearwaters, gannets, prions, kahawai, and saury).  But during this survey effort we collected a lot of synoptic environmental data to describe these habitats, including continuous depth and temperature data along our track, nine CTD water column profiles of temperature, salinity and florescence (productivity) from the surface to the seafloor, and continuous prey (zooplankton) availability data with our transducer (echosounder).

So, now that we have absence data, we need presence data. But, the winds are howling again and are predicted to continue for the next few days. As we hunker down in a beautiful protected cove I know the blue whales continue to search this region for dense food patches, unencumbered by human-perceived obstacles of high wind and swell. So, while my Kiwi friends are right – this summer is not like previous years – I also know that it is the effects of these dynamic weather patterns that we have come so far, and worked so hard, to study. Even as my patience wears thin and my frustrations mount, I will continue to wait to pounce on the right weather window to collect our needed presence data (and more absence data too, I’m sure).

Our research team collecting absence data aboard the RV Star Keys:

….aaaand we’re off! The blue whale team heads to New Zealand

By Dawn Barlow, MSc Student, Geospatial Ecology of Marine Megafauna Lab, Department of Fisheries and Wildlife, Oregon State University

Today we are flying to the other side of the world and boarding a 63-foot boat to study the largest animals ever to have inhabited this planet: blue whales (Balaenoptera musculus). Why do we study them, and how will we do it? Before I tell you, first let me say that no fieldwork is ever straightforward, and consequently no fieldwork lacks exciting learning opportunities. I have learned a lot about the logistics of an international field season in the past month, which I will share with you here!

The South Taranaki Bight, which lies between the north and south islands of New Zealand, is the study area for this survey.
Research vessel Star Keys will be our home for the month of February as we look for whales.

Unmanned aerial systems (UAS, a.k.a. “drones”) are becoming more prevalent in our field as a powerful and minimally invasive tool for studying marine mammals. Last year, our team was able to capture what we believe is the first aerial footage of nursing behavior in baleen whales, in addition to feeding and traveling behaviors. And beyond behavior, these aerial images contain morphological and physiological information about the whales such as how big they are, whether they are pregnant or lactating, and if they are in good health. I’ll start making a packing list for you to follow along with. So far it contains two drones and all of their battery supplies and chargers.

Aerial image of a blue whale mother and calf captured by a drone during the 2016 field season.

Perhaps you read my first GEMM Lab blog post, about identifying individual blue whales from photographs? Using these individual IDs, I plan to generate an abundance estimate for this blue whale population, as well as look at residency and movement patterns of individuals. Needless to say, we will be collecting photo-ID images this year as well! Add two large pelican cases with cameras and long lenses to the packing list.

Blue whale photo-ID image, showing the left and right sides of the same whale. I have identified 99 unique individuals so far, and look forward to adding to our catalog this year!

Now wouldn’t it be great to capture video of animal behavior in some way other than with the UAS? Maybe even from underwater? Add two GoPros and all of their associated paraphernalia to the mounting gear pile.

Now, bear with me. There is a wealth of physiological information contained in blue whale fecal matter. And when hormone analysis from fecal samples is paired with photogrammetry from UAS images, we can develop a valuable picture of individual and population-level health, stress, nutrition, and reproductive status. So, say we are able to scoop up lots of blue whale fecal samples – wouldn’t that be fantastic? Yes! Alright, add two nets, a multitude of jars, squirt bottles, and gloves to the gear list. And then we still need to bring them back to our lab here in Newport. How does that happen? Well, we need to filter out the sea water, transfer the samples to smaller tubes, and freeze them… in the field, on a moving vessel. Include beakers, funnels, spatulas, and centrifuge tubes on the list. Yes, we will be flying back with a Styrofoam cooler full of blue whale “poopsicles”. Of course, we need a cooler!

Alright, and now remember the biopsy sampling that took place last season? Collecting tissue samples allows us to assess the genetic structure of this population, their stable isotopic trophic feeding level, and hormone levels. Well, we are prepared to collect tissue samples once again! Remember to bring small tubes and scalpel blades for storing the samples, and to get ethanol when we arrive in Wellington.

An important piece in investigating the habitat of a marine predator is learning about the prey they are consuming. In the case of our blue whales, this prey is krill (Nyctiphanes australis). We study the prey layer with an echo sounder, which sends out high frequency pings that bounce off anything they come in contact with. From the strength of the signal that bounces back it is possible to tell what the composition of the prey layer is, and how dense. The Marine Mammal Institute here at OSU has an echo sounder, and with the help of colleagues and collaborators, positive attitudes, and perseverance, we successfully got the transducer to communicate with the receiver, and the receiver to communicate with the software, and the software to communicate with the GPS.  Add one large pelican case for the receiver. Can we fit the transducer in there as well? Hmmm, this is going to be heavy…

Blue whale team members and colleagues troubleshoot and test the Simrad EK60 echo sounder before packing it to take to New Zealand.

Now the daunting, ever-growing to-do lists have been checked off and re-written and changed and checked off again. The mountain of research gear has been evaluated and packed and unpacked and moved and re-evaluated and packed again. The countdown to our departure date has ended, and this evening Leigh, Todd, and I fly out of Portland and make our way to Wellington, New Zealand. To think that from here all will be smooth and flawless is naïve, but not being able to contain my excitement seems reasonable. Maybe it’s the lack of sleep, but more likely it’s the dreams coming true for a marine ecologist who loves nothing more than to be at sea with the wind in her face, looking for whales and creatively tackling fieldwork challenges.

In the midst of the flurry of preparations, it can be easy to lose sight of why we are doing this—why we are worrying ourselves over poopsicle transport and customs forms and endless pelican cases of valuable equipment for the purpose of spending several weeks on a vessel we haven’t yet set foot on when we can’t even guarantee that we’ll find whales at all. This area where we will work (Figure 1) is New Zealand’s most industrially active region, where endangered whales share the space with oil rigs, shipping vessels, and seismic survey vessels that have been active since October in search of more oil and gas reserves. It is a place where we have the opportunity to study how these majestic giants fit into this ecosystem, to learn what about this habitat is driving the presence of the whales and how they’re using the space relative to industry. It is an opportunity for me as a scientist to pursue questions in ecology—the field of study that I love. It is also an opportunity for me as a conservation advocate to find my voice on issues of industry presence, resource extraction, and conflicts over ocean spaces that extend far beyond one endangered species and one region of the world.

Fieldwork preparations have made clear to me once again the strength and importance of collaboration in science. Kim Bernard from OSU’s College of Earth, Ocean, and Atmospheric Sciences and Craig Hayslip from the Marine Mammal Institute’s Whale Telemetry Group spent half a day troubleshooting the echosounder with us. Western Work Boats has manufactured a pole mount for the echosounder transducer, and Kristin Hodge is joining us from Cornell University’s Bioacoustics Research Program to assist with data collection. Callum Lilley and Mike Ogle from the New Zealand Department of Conservation will join us in Wellington to collect the biopsy samples, and Rochelle Constantine and Scott Baker will facilitate the archiving and transport of the tissue samples back to Newport for analysis. Scientific colleagues at NIWA will collaborate on oceanographic aspects and conduct stable isotope analysis of tissue samples. We are also grateful to the indispensable logistical support from Kathy Minta and Minda Stiles in the OSU Marine Mammal Institute. And, of course we could not do any of this work without the generous funding support from The Aotearoa Foundation, The New Zealand Department of Conservation, Greenpeace Aotearoa New Zealand, OceanCare, The International Fund for Animal Welfare Oceanea Office, Kiwis Against Seabed Mining, the OSU Marine Mammal Institute, and the Thorpe Foundation. Our science is stronger when we pool our energy and expertise, and I am thrilled to be working with this great group of people.

Stay tuned, the next several blogs will be posted from the field by the New Zealand blue whale team!

Assembling a Toolbox

By Dawn Barlow, MSc student, Oregon State University

toolbox
Source: https://www.ohrd.wisc.edu/home/portals/0/toolbox.jpg

The season has shifted since the post I wrote this summer about diving into the world of New Zealand blue whales and the beginnings of my masters research. My fieldwork will take place during the upcoming austral summer, which will require me to miss the winter term here on campus. This quarter, I have put my research on the back burner for the time being in favor of a full load of coursework. But my project is still there, simmering subtly and persistently, and giving relevance to the coursework that I’m focusing my energy on this fall term.

As an undergraduate student, I acquired a broad scientific background and had the opportunity to dabble in the areas of biology that piqued my interest. I arrived here with a basic understanding of chemistry, physics, cell biology, anatomy, marine ecology and conservation biology. I gained experience working in the field with intertidal sea stars, snails, mussels, crabs and barnacles, with bottlenose dolphins and with humpback whales. But now my focus has narrowed as I’ve honed in on the specific questions that I will pursue over the next two years. My passion lies in marine ecology and conservation. Now, as a graduate student studying the ecology of a little-known population in a highly industrial area, this passion can come to fruition. For my masters, I hope to do the following:

A) Use photo-identification analysis to obtain a population abundance estimate for blue whales in New Zealand

B) Investigate blue whale residency and distribution patterns in New Zealand waters

C) Develop a comprehensive blue whale habitat use model for the South Taranaki Bight region of New Zealand, which incorporates physical and biological data

Down the road I hope to have implemented a capture-recapture abundance estimate model that best fits the dynamics of this population of blue whales, to have mapped where sightings have occurred and where the highest densities of blue whales are found in both space and time, and to have paired blue whale presence and absence with prey distribution, remote-sensed environmental data, and in situ oceanographic data. But how does one accomplish these things? I need a toolbox to draw from. And so this fall, I am assembling my toolbox, learning programs and analytical skills. I am taking methods courses—statistics, data management in R, analysis in GIS, methods in physiology and behavior of marine megafauna—that are no longer explorations into the world of natural science, but rather tools for exploring, identifying, and interpreting specific phenomena in ecology. While each comes with its own hiccups and headaches (see Florence’s post about this…), they are powerful tools.

Aside from coursework, the research I’m conducting has gained weight and relevance beyond being an investigation in ecology. My study area lies in the South Taranaki Bight of New Zealand, which is a contentious proposed seabed mining site for iron sands. As an undergraduate student I read case studies and wrote papers on the environmental impacts of industry, and I decided to go graduate school because I want to do research that has direct conservation applications. Last week I compiled all the data I’ve processed on blue whale sightings, seasonal residency, and photo identification for the South Taranaki Bight, which will be included as evidence submitted in environmental court in New Zealand by my advisor, Dr. Leigh Torres. “Applied conservation science” has been an abstract idea that has excited and motivated me for a long time, and now I am partaking in this process, experiencing applied conservation science firsthand.

And so my toolbox is growing, and the scope of my work is simultaneously narrowing in focus and expanding in relevance. The more tools I acquire, the more excited I am to apply them to my research. As I build my toolbox this fall, this process is something I look forward to enhancing while I’m in the field, when I dig deeper into data analysis, and as I grow as a conservation scientist.

A blue whale dives in the South Taranaki Bight, New Zealand. Photo by Leigh Torres.
A blue whale dives in the South Taranaki Bight, New Zealand. Photo by Leigh Torres.

Blue whale portraits: pieces of the puzzle

By Dawn Barlow, MSc Student, Oregon State University

Perhaps you’ve read some posts about New Zealand blue whales on this blog from the past field season in the South Taranaki Bight (STB). I know I eagerly awaited updates from the field while the team was in New Zealand and I was in Southern California, finishing undergrad and writing funding proposals and grad school applications. Now that undergrad is done and dusted, I’ve arrived in Newport and begun to settle in to my next chapter as the newest member of the GEMM Lab, joining the blue whale research team as a MSc student in OSU’s Department of Fisheries and Wildlife. Since no blue whale news has made it onto this blog in some time, I’m excited to share what has happened since the team returned from the field!

As you may have heard from Leigh, Callum, and Kristin, 2016 was a fruitful field season. In nearly 1,500 miles of vessel surveys, the team documented blue whale foraging behavior, a pair of racing whales, four mother-calf pairs, what may be the first aerial footage of nursing behavior in baleen whales (video below), and a whale with apparent deformities. Five hydrophones units were deployed, fecal and biopsy samples were collected, oceanographic conditions were measured, and photos were taken.

I was welcomed into the GEMM Lab in early July, and presented with a workspace, a hard drive with thousands of photos, new software programs to learn, wonderfully accessible tea and coffee, and tasked with creating a photo-ID catalog of all the blue whales our team photographed this past field season. Here’s a great thing about blue whales: while they may be tricky to study, when someone sees a blue whale they are often excited to report it. In addition to the data collected by our team during the 2016 season and the 2014 pilot season, we are incorporating many photo-documented sightings of blue whales from all around New Zealand that we have received from collaborative researchers, whale watch organizations, and fishing vessels alike captured between 2004 and 2016. All these photos are precious data to us, as we can use them to better understand their ecology.

There are many unanswered questions about this population of blue whales in New Zealand — How many are there? Just how big are they? Do they stay in New Zealand year-round or are they migratory? Through the photo-ID analysis that I’ve done, we are just beginning to piece together some answers. We have now compiled records of sightings in New Zealand from every month of the year. I’ve identified 94 unique individual blue whales, 26 of which were sighted in the STB during the 2016 season. Five whales were seen in multiple years (Figure 1), including one whale that was seen in three different years, in three different places, and with three different calves! And what might all of this mean? At this point it’s still speculative, but these findings hint at year-round residency and seasonal movement patterns within New Zealand waters… with more data and more analysis I will be able to say these things more conclusively.

New Zealand Blue Whale Photo-ID

NZ Blue Whale Photo-ID
Figure 1. Blue whale photographed off of Westport on 31 January 2013 (above) by the Australian Antarctic Division (data provided by Mike Double), and in the South Taranaki Bight on 2 February 2016 (below). Note how the tear in the dorsal fin has healed over the three-year period.

Perhaps you’ve read Leila’s post about photogrammetry, and how she is able to make measurements using aerial photographs captured using an Unmanned Aerial System (UAS, aka ‘drone’). Using the same method, I will soon be able to tell you how long these whales really are (Figure 2).

sighting 22 UAS reduced
Figure 2. An aerial photograph captured with the UAS during the 2016 season, which will be used to measure the length of these whales using photogrammetry.

How many of them are there? Well, that’s a trickier question. Using a straightforward abundance calculation based on our rate of re-sightings, the estimate I came up with is 594 ± 438. In other words, I can say with 95% confidence that there are between 156 and 1031 blue whales in New Zealand. How helpful is this? Well, not very! The wide confidence intervals in this estimate are problematic, and it is difficult to draw any conclusions when the range of possible numbers is so large. So stay tuned as I will be learning more about modeling population abundance estimates in order to provide a more precise and descriptive answer.

But stepping back for a minute, what does it matter how many whales there are and what they’re doing? In 2014, Leigh demonstrated that the STB is an important foraging ground for these blue whales. However, the STB is also a region heavily used by industry, experiencing active oil and gas extraction (Figure 3), seismic surveying, shipping traffic, and proposed seafloor mining. If we don’t know how the blue whales are using this space, then how can we know what effect the presence of industry will have on their ecology? It is our hope that findings from this study can guide effective conservation and management of these ocean giants as well as the ecosystem they are part of.

Figure 2. A blue whale surfaces in front of an oil rig in the South Taranaki Bight, New Zealand. Photo by Deanna Elvines.
Figure 3. A blue whale surfaces in front of an oil rig. Photo by Deanna Elvines.

Keeping these goals in mind, I’m eagerly awaiting the start of our 2017 field season in the STB. As I look through all these photos I feel like I’m getting to know this group of whales just a little bit and I look forward to being on the water seeing them myself, maybe even recognizing some from the 2016 photos. More time on the water and more data will bring us closer to the piecing together the story of these whales, and inevitably open doors to more questions than we started with. And in the meantime, I’m grateful for the community I’ve found here in the GEMM Lab, at Hatfield Marine Science Center, and in Newport.