Tag: conservation

Scratching the Surface

By Dr. Leigh Torres, Assistant Professor, Oregon State University, Geospatial Ecology of Marine Megafauna Lab

I have been reminded of a lesson I learned long ago: Never turn your back on the sea – it’s always changing.

The blue whales weren’t where they were last time. I wrongly assumed oceanographic patterns would be similar to our last time out in 2014 and that the whales would be in the same area. But the ocean is dynamic – ever changing. I knew this. And I know it better now.

Below (Fig. 1) are two satellite images of sea surface temperature (SST) within the South Taranaki Bight and west coast region of New Zealand that we surveyed in Jan-Feb 2014 and again recently during Jan-Feb 2016. The plot on the left describes ocean surface conditions in 2014 and illustrates how SST primarily ranged between 15 and 18 ⁰C. By comparison, the panel on the right depicts the sea surface conditions we just encountered during the 2016 field season, and a huge difference is apparent: this year SST ranged between 18 and 23 ⁰C, barely overlapping with the 2014 field season conditions.

Figure 1. A comparison of satellite images of sea surface temperature (SST) in the South Taranaki Bight region of New Zealand between late January 2014 and early February 2016. The white circles on each image denote where the majority of blue whales were encountered during each field season.
Figure 1. A comparison of satellite images of sea surface temperature (SST) in the South Taranaki Bight region of New Zealand between late January 2014 and early February 2016. The white circles on each image denote where the majority of blue whales were encountered during each field season.

While whales can live in a wide range of water temperatures, their prey is much pickier. Krill, tiny zooplankton that blue whales seek and devour in large quantities, tend to aggregate in pockets of nutrient-rich, cool water in this region of New Zealand. During the 2014 field season, we encountered most blue whales in an area where SST was about 15 ⁰C (within the white circle in the left panel of Fig. 1). This year, there was no cool water anywhere and we mainly found the whales off the west coast of Kahurangi shoals in about 21 ⁰C water (within the white circle in the right panel of Fig. 1. NB: the cooler water in the Cook Strait in the southeast region of the right panel is a different water mass than preferred by blue whales and does not contain their prey.)

The hot water we found this year across the survey region can likely be attributed, at least in part, to the El Niño conditions that are occurring across the Pacific Ocean currently. El Niño has brought unusually settled conditions to New Zealand this summer, which means relatively few high wind events that normally churn up the ocean and mix the cool, nutrient rich deep water with the hot surface layer water. These are ideal conditions for Kiwi sun-bathers, but the ocean remains highly stratified with a stable layer of hot water on top. However, this stratification does not necessarily mean the ocean is un-productive – it only means that the SST satellite images are virtually useless for helping us to find whales this year.

Although SST data can be informative about ocean conditions, it only reflects what is happening in the thin, top slice of the ocean. Sub-surface conditions can be very different. Ocean conditions during our two survey periods in 2014 and 2016 could be more similar when compared underwater than when viewed from above. This is why sub-surface sensors and data collection is critical to marine studies. Ocean conditions in 2014 and 2016 could both potentially provide good habitat for the whales. In fact, where and when we encountered whales during both 2014 and 2016 we also detected high densities of krill through hydro-acoustics (Fig. 2). However, in 2014 we observed many surface swarms of krill that we rarely saw this recent field season, which could be due to elevated SST. But, we did capture cool drone footage this year of a brief sub-surface foraging event:

An overhead look of a blue whale foraging event as the animal approaches the surface. Note how the distended ventral (throat) grooves of the buccal cavity (mouth) are visible. This is a big gulp of prey (krill) and water. The video was captured using a DJI Phantom 3 drone in the South Taranaki Bight of New Zealand in on February 2, 2016 under a research permit from the New Zealand Department of Conservation (DOC) permit # 45780-MAR issued to Oregon State University.

Figure 2. An echo-sounder image of dense krill patches at 50-80 m depth captured through hydroacoustics in the South Taranaki Bight region of New Zealand.
Figure 2. An echo-sounder image of dense krill patches at 50-80 m depth captured through hydroacoustics in the South Taranaki Bight region of New Zealand.

Below are SST anomaly plots of January 2014 and January 2016 (Fig. 3). These anomaly plots show how different the SST was compared to the long-term average SST across the New Zealand region. As you can see, in 2014 (left panel) SST conditions in our study area were ~1 ⁰C below average, while in 2016 (right panel) SST conditions were ~1 ⁰C above average. So, what are normal conditions? What can we expect next year when we come back to survey again for blue whales across this region? These are challenging questions and illustrate why marine ecology studies like this one must be conducted over many years. One year is just a snap shot in the lifetime of the oceans.

Figure 3. Comparison of sea surface temperature (SST) anomaly plots of the New Zealand region between January 2014 (left) and January 2016 (right). The white box in both plots denotes the general location of our blue whale study region. (Apologies for the different formats of these plots - the underlying data is directly comparable.)
Figure 3. Comparison of sea surface temperature (SST) anomaly plots of the New Zealand region between January 2014 (left) and January 2016 (right). The white box in both plots denotes the general location of our blue whale study region. (Apologies for the different formats of these plots – the underlying data is directly comparable.)

Like all marine megafauna, blue whales move far and fast to adjust their distribution patterns according to ocean conditions. So, I can’t tell you what the ocean will be like in January 2017 or where the whales will be, but as we continue to study this marine ecosystem and its inhabitants our understanding of ocean patterns and whale ecology will improve. With every year of new data we will be able to better predict ocean and blue whale distribution patterns, providing managers with the tools they need to protect our marine environment. For now, we are just beginning to scratch the (sea) surface.

 

 

 

Biopsy sampling blue whales in New Zealand

By: Callum Lilley

Senior Ranger, Marine – Department of Conservation, Taranaki, New Zealand

During the end of January, I had the privilege to be part of the research team studying blue whales in the South Taranaki Bight, New Zealand.  My role, along with assisting with visual survey, was to obtain biopsy samples from whales using a Paxarm modified veterinary rifle.   This device fires a plastic dart fitted with a sterilized metal tip that takes a small skin and blubber sample for genetic and stable isotope analysis. This process is very carefully managed following procedures to ensure that the whales are not put under any undue stress.  Biopsy sampling provides a gold mine of genetic and dietary information to help us understand the dynamics of this whale population.

Although firing a dart at a creature that is considerably larger than a city bus sounds reasonably easy, it is rarely the case.  The first challenge is to find whales within a large expanse of ocean.  The team then needs to photograph the side of each animal and take note of any distinctive features so that each individual is only sampled once.  Sometimes other work will be undertaken (such as collecting fecal samples, or deploying a drifting hydrophone or unmanned aerial system/drone).  Finally the team will attempt to get close enough to the whales, while taking care not to unduly disturb them, to get a biopsy sample.  Wind, vessel movement, glare, the length of time whales spend underwater and the small target they sometimes present above the water are further challenges.

The video below shows a successful biopsy attempt.  It is a well-coordinated team effort that relies on great communication. You can hear observer Todd Chandler direct the skipper of the vessel Ikatere into position while keeping me (the biopsy sampler) informed as to which whale is surfacing and where.  From the vantage point of the flying bridge, Todd can see the whales’ position and movement (my view is limited from the lower deck).  Todd points out where the whale is surfacing and it momentarily presents a target.  This was the second sample from the two racing whales previously discussed by Dr. Torres, so it will be interesting to see their relationship to one-another.

The ideal angle to approach a whale to take a biopsy sample is from behind at a 45 degree angle, as this causes the least disturbance.  The following video was taken from an unmanned aerial system.  It shows the vessel Ikatere approaching from the whale’s left flank. Department of Conservation (DOC) biodiversity ranger Mike Ogle is on the bow of the vessel and fires a biopsy dart at the whale.  After the biopsy is taken the vessel maneuvers to collect the dart/sample from the water while the whale continues to travel.

In addition to blue whale samples, the DOC permit issued to Oregon State University also allowed for opportunistic sampling of other whales.  The following video was taken during an encounter with a large pod of pilot whales.  The video shows how the lightweight dart bounces off the animal and floats in the water.  Care is taken to communicate its location to the skipper who positions the vessel so it can be retrieved with a net.

Once samples have been retrieved they are handled very carefully to prevent contamination.  The sample is split, with some preserved for genetic analysis and the rest for stable isotope analysis.  Analysis of genetic samples provides information on sex, abundance (through genetic capture-recapture, which is calculated by analyzing the proportion of individuals repeatedly sampled over subsequent seasons), and relationships to other blue whale populations.  Stable isotope analysis provides information on diet.  Also, a portion of all samples will be stored for potential future opportunities such as hormone and fatty acid analysis. It blows me away how much information can be gleaned from these tiny samples!

 

“This is what I would do if I weren’t afraid” – New Zealand blue whale field season 2016

By Dr. Leigh Torres, Assistant Professor, Oregon State University, Geospatial Ecology of Marine Megafauna Lab

Two years ago I documented a blue whale foraging ground in an area of New Zealand called the South Taranaki Bight (STB) – the country’s most industrially active marine area with intense oil and gas exploration and extraction since the 1970’s, elevated vessel traffic, and potential seabed mining (Figure 1). Over just five days of survey effort we observed 50 blue whales and documented foraging behavior. But we still know next to nothing about where and when blue whales are in the STB, how many whales use this area, how important this area is as a feeding area, or to what population the whales belong. Without answers to these questions effective management of human activities in the region to protect the whales and their habitat is unfeasible.

I am now heading back to New Zealand to collect the data needed to answer these questions that will enable successful management. That’s my goal.

Figure 1. Illustration of a space-use conflict between industry activity and blue whales in the South Taranaki Bight, which lies between the north and south islands of New Zealand. Blue whale sightings and strandings recorded between 1970 and 2012.
Figure 1. Illustration of a space-use conflict between industry activity and blue whales in the South Taranaki Bight, which lies between the north and south islands of New Zealand. Blue whale sightings and strandings recorded between 1970 and 2012.

Such research costs money. In collaboration with the Bioacoustic Research Program at Cornell University (birds.cornell.edu/brp), we are deploying five hydrophones to listen for blue whales across the region for 2 years. We will conduct vessel surveys for 1 month in each year to find whales and collect data on their habitat, behavior, and individual occurrence patterns. As far as field research projects go, this work is not very expensive, but we still need to pay for vessel time, equipment, and personnel time to collect and analyze the data. This is an ugly truth of scientific research – it costs money and there is not a lot out there.

For two years I’ve had my fund raising hat on (Not my favorite hat. I much prefer my research hat). I believe that industry groups active in the STB should take an active role in supporting the necessary research. They exploit the natural resources in the region and should therefore take responsibility for ensuring the ecosystem’s sustainability and health. Right? They did not agree.

I emphasized to these groups that by supporting the project they would demonstrate their environmental responsibility and ultimately be engaged in discussions of management options based on project findings. Despite hundreds of emails, phone calls and discussions, all the oil and gas companies, the seabed mining group, and the maritime traffic organization declined to fund the project, claiming lack of funds or lack of relevance to their interests. Meanwhile, other groups who prioritize conservation management are supporting the project. I am grateful to The Aotearoa Foundation, The National Geographic Society Waitt Foundation, The New Zealand Department of Conservation, Greenpeace New Zealand, OceanCare, Kiwis Against Seabed Mining, and an anonymous donor.

Lately I have been reading Sheryl Sandberg’s poignant book, Lean In, which I feel is a call to women to take responsibility for our equality and leadership. Those familiar with this book will recognize the opening of my blog title from her valid push for women to take more risks and push ourselves beyond our comfort zones. In many ways I feel I am doing this now. It would be much easier for me to withdraw from this project, say I tried, and let things carry on until someone else takes the challenge. Funding is short, last minute contract issues abound, equipment logistics are running late, I fear political pushback, and I have a sore throat. But it’s time for this project to happen. It’s time to recognize biodiversity’s innate right to healthy habitat. It’s time for industry groups to acknowledge their potential impacts on blue whales through elevated ocean noise, vessel strikes, and habitat degradation and displacement. It’s time for management to have the tools to act.

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

I remain hopeful that industry groups will engage in this research effort. Through diplomacy, transparency and robust science I want to bring together industry, NGOs, and management groups to develop effective conservation strategies to protect blue whales and their habitat in the STB. Collaboratively we can balance industry activity and biodiversity protection.

Since reading Lean In, I’ve been wondering if the conservation movement suffers because of women’s reluctance to challenge, take risks, and ‘sit at the table’ as Sandberg says. The conservation field is heavily dominated by women. For progress to happen we must be willing to force issues, be perceived as aggressive, and not be nice all the time. Just like men are expected to be.

Over the next four weeks colleagues and I will conduct research in the STB on blue whales. Stay tuned to this blog for updates.