Narwhals in Scoresby Sound

A version of this post originally appeared on narwhals2017.com. It has been lightly edited and republished with permission by the researchers of the Greenland Institute of Natural Resources (Pinngortitaleriffik).

In 2010, researchers discovered a good place in East Greenland to work with narwhals (Source: Carsten Egevang/Pinngortitaleriffik).

In 2010, Mads Peter Heide-Jørgensen and his colleague Hans Christian Schmidt discovered that Hjørnedal in Scoresby Sound in the Greenland Sea was an ideal place for the live capturing of narwhals. They have been capturing narwhals in West Greenland and Canada for 20 years but needed a good place in East Greenland where they could work with the whales. The first capturing and tagging of narwhals in East Greenland took place in Hjørnedal in 2010, and the locality quickly showed its potentials. There is usually good weather with little wind, and there is no ice that could make trouble in the nets used.

There are not as many narwhals in Scoresby Sound as at some of the other localities in the Arctic, but there were enough for their work, and– very importantly– there was a good group of Iñupiat hunters from Ittoqqortormiit that were willing to assist with the operations. Thus, the team decided to establish a small field station with two home-made houses for use during the month-long stay at the camp. In 2017, they set out to capture and tag at least 10 narwhals in Hjørnedal.

The project to research the narwhals was the biggest marine mammal venture ever undertaken by Pinngortitaleriffik (Source: Pinngortitaleriffik).

Outi Tervo, one of the project’s researchers, sailed around Scoresby Sound putting out listening buoys to record narwhal sounds. She also put Acousonde tags on the whales that deploy hydrophones to record narwhal sounds, and also depth and orientation sensors that tell how the narwhal moves when diving. In Hjørnedal, scientists and hunters took turns sitting at the top of the mountain scouting for narwhals. When one was spotted, everybody worked together in order to calmly lead the narwhals closer to shore where they were instrumented with satellite tags, Acousonde tags and heart-rate recorders.

The narwhal is a medium-sized whale in the Arctic known for its large tusk (Source: Daniel Fridriksson/Pinngortitaleriffik).

Researcher Eva Garde’s main function in the East Greenland narwhal project was as a narwhal-observer on the R/V “Pâmiut.” “Pâmiut” is the Greenland Institute of Natural Resources research vessel used mainly for open-water investigations of shrimp and Greenland halibut. The ship is a stern trawler furnished with wet and dry laboratories as well as computers, hydrographical equipment and other equipment relevant to collection and processing of samples. It departed from the dock in Reykjavik on 12 August heading for Scoresby Sound in East Greenland with a scheduled arrival 24-36 hours later.

The last bit of the fieldwork puzzle came together in August with the start of the aerial survey, adding yet another and final aspect to the list of narwhal related research in Scoresby Sound. The company where the researchers chartered the Twin Otter airplane was based in Akureyri, Iceland, and the team spent the first day installing the recording equipment in the plane. Yes, it took a whole day. The plane needed bubble windows so the observers could look directly under the plane, making sure that animals close to the plane were detected.

The team’s gear included a communication system, a video camera, a GPS tracking system and a recording device called a geometer (Source: Pinngortitaleriffik).

The team also had a communication system, a video camera, a custom-built GPS tracking system and a recording device called a geometer that they invented together with Icelandic colleagues. It worked this way: observers detected a whale, they then pressed a button on the geometer that recorded and logged the declination angle to the whale. Since the researchers flew at a fixed altitude (700 feet), using simple geometry gave them the distance to the whale. After the survey was completed, the team had frequency of distances, with more observations at shorter distance to the plane’s track line. These distances helped model the detection function for the observers and gave them an idea on how many whales the observers saw. This “distance sampling” technique is essential for estimating abundance of wildlife in large areas.

By using two observers on either side of the plane, the researchers also calculated the perception bias, i.e. how many whales are missed by the front or rear observer. Finally, they accounted for availability bias, i.e. some whales were unavailable to the observers because they were below the water surface as the plane flew over. The researchers used the percentage of time the whales spent at the surface with measurements from narwhals tagged with satellite transmitters in previous years in Hjørnedal.

Narwhals spend most of their time close to calving glaciers (Source: Pinngortitaleriffik).

After testing the equipment, the researchers were off toward Scoresby Sound. They started the survey in Gåsefjord, where they knew to look out for “Paamiut.” And there, after a few kilometers flown, they spotted the ship going into the fiord. Not long after, the team detected a group of narwhals. The whales moved slowly through the water, some in pairs, others alone. The researchers even spotted a mother with a newborn and an older calf, and counted approximately 30 whales in total. They seemed to just be hanging around in the small bay close to a calving glacier filling up the bay with icebergs. Since narwhals tend to spend most of their time close to calving glaciers, the researchers made sure to take pictures of all of the glaciers in the fiord. Well, the pilots took the pictures – the observers were busy searching for whales.

In Hjørnedal, scientists and hunters took turns scouting for narwhals (Source: Pinngortitaleriffik).

After finalizing the planned transects in Gåsefjord, the team left for Constable Point, making sure to land there while the airfield was open. They unpacked, looked at the muskox close by, had dinner and finished the securing of recorded data for the day. After sitting in the plane all day, they all needed to stretch their legs, so they decided to take a run along the airstrip. Since there was a polar bear at the airfield last week, they were all on the lookout for something large and white that moves, thinking next time to bring a flare gun…

For more information on the project, please view the researchers’ field diary at narwhals2017.com, recorded from four different field stations in Scoresby Sound and along the coast of East Greenland.

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Putting Your Best Tusk Forward: Narwhals and Climate Research

A pod of narwhals in Admiralty Inlet, Canada (Source: Kristin Laidre).

In 1576, Queen Elizabeth I paid the equivalent of half a million dollars for a unicorn horn, which she believed could neutralize poison. Of course, it wasn’t a unicorn horn at all, but a narwhal tusk, remarkable in its own right.

Today, over 440 years later, narwhals continue to surprise and attract attention. A recent paper in Biology Letters by Kristin Laidre et al. examined narwhal visits to glacial fronts in West Greenland.

“We don’t fully understand the relation between narwhals and glaciers,” professor Mads Heide-Jørgensen of the Greenland Institute of Natural Resources told GlacierHub. Laidre added, “Narwhals in places like the Canadian Arctic, for example, have limited access to glacial habitat. However, in Greenland, most narwhals are close to glaciers in summer because Greenland is so glaciated, and there are glaciers along the entire coastline.”

It has long been observed that narwhals visit glacial fronts in the summer and autumn, but it is unknown why they seek out this habitat. “Glaciers are productive regions,” commented Laidre. “They attract prey, there’s upwelling and nutrient cycling, and sometimes even osmotic shock to small invertebrates which attracts fish… We hope future studies will help us understand this, but we don’t know exactly why they go there.” Belugas, the “sister species” to the narwhal, also favor freshwater habitat in the summer, seeking out shallow water estuaries.

To begin answering this question, Laidre took a novel approach, forming an international, cross-disciplinary team that included scientists from the U.S., Denmark, and the U.K. “The idea was to get biologists and glaciologists to collaborate and share data in an interdisciplinary way,” Laidre said.

The team evaluated which glacial characteristics draw narwhals by collecting data from 15 satellite-tagged whales and following their movements through the fjords of Melville Bay in West Greenland. The narwhals demonstrated three preferences: they spent more time at glaciers that discharge a fresher, rather than siltier melt; they preferred slower-flowing glaciers, which are more stable and calve less; and they favored thicker glacial fronts, perhaps because they maximize access to freshwater.

A narwhal is tagged for research (Source: Mads Heide-Jørgensen).

Sea ice also provides important habitat for narwhals. “All narwhal populations winter, and some even summer, in dense sea ice concentrations,” said Heide-Jørgensen. In summer, narwhals spend time in the high Arctic where ice has receded, and in fall, the ocean freezes solid, pushing the narwhals away from shore, Laidre explained. “They swim away from the forming ice and move offshore, where they overwinter in dense ice cover with cracks so they can breathe. Narwhals are highly associated with sea ice, perhaps the most of all whales,” he said.

Heide-Jørgensen indicated that narwhals will seek out the sea ice when it decreases in coverage rather than wintering in open water. “Reduction of sea ice therefore implies a reduction in habitat, and this will again introduce a reduction in prey base or carrying capacity. In short, less sea ice means less narwhal habitat and eventually less narwhals,” he said.

Laidre agreed that “changes in sea ice and the marine ecosystem will likely be the most important factor” to the future of narwhals as climate changes. Since 1979, sea ice freeze-up has occurred almost a month later in Baffin Bay and Melville Bay, where this study took place, and glaciers, of course, are retreating. But far from being simple victims of global warming, narwhals can aid in the collection of data that can help mitigate climate change.

The glaciated fjords of Greenland provide important habitat for narwhals, and are changing rapidly (Source: Mads Heide-Jørgensen).

In 2005 and 2007, Laidre took advantage of narwhals’ capacity for deep dives and tendency to winter in sea ice, outfitting narwhals with temperature and depth sensors. Narwhals regularly dive over 1,700 meters to hunt bottom-dwellers like Greenland halibut, and 90 percent of the recorded dives reached the bottom. This method effectively turned narwhals into self-powered oceanographic instruments and allowed the researchers to collect wintertime data in Baffin Bay, the dearth of which had long been felt in climate records.

Perhaps, most importantly, the study proved that narwhals can constitute an effective ocean observation platform in remote areas where dense ice cover prevents regular instrument deployment. In this way, narwhals are even more magical than the unicorn Queen Elizabeth I imagined.

 

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Roundup: Glacier Lakes, Narwhals, and Water Stress

Glacier Lake Deepening in the Himalayas

From Water: “This paper investigates physical processes in the four sub-basins of Ngozumpa glacier’s terminal Spillway Lake for the period 2012–2014 in order to characterize lake deepening and mass transfer processes. Quantifying the growth and deepening of this terminal lake is important given its close vicinity to Sherpa villages down-valley… In areas of rapid deepening, where low mean bottom temperatures prevail, thin debris cover or bare ice is present. This finding is consistent with previously reported localized regions of lake deepening and is useful in predicting future deepening.”

You can read more about glacier lake deepening here.

Overview of the Tsho Rolpa Lake in the Rowaling Valley, Spillway Lake in the Gokyo Valley, and Imja Lake in the Khumbu Valley (Source: Water).

 

Narwhals To Help Monitor Melting Glaciers

From New Scientist: “An iconic whale species will soon be aiding climate change research. Narwhals are spending more time near melting sea ice and researchers hope to exploit this new behavior by tagging the mammals with temperature sensors to help us accurately monitor underwater sea ice melt for the first time.”

You can read more about narwhals–marine mammals, once confused with unicorns–and glacier monitoring here.

A Narwhal (Source: New Scientist).

 

A Study of Water Stress in Kyrgyzstan

From Water: “Water vulnerabilities in Central Asia are affected by a complex combination of climate-sensitive water sources, trans-boundary political tensions, infrastructure deficiencies and a lack of water management organization from community to federal levels. This study aims to clarify the drivers of water stress across the 440 km Naryn River basin, headwater stem to the Syr Darya and the disappearing North Aral Sea… Surveys indicate that current water stress is primarily a function of water management and access issues resulting from the clunky transition from Soviet era large-scale agriculture to post-Soviet small-plot farming. Snow and ice meltwaters play a dominant role in the surface and ground water supplies to downstream communities across the study’s 4220 m elevation gradient, so future increases to water stress due to changes in volume and timing of water supply is likely given frozen waters’ high sensitivities to warming temperatures. The combined influence of social, political and climate-induced pressures on water supplies in the Naryn basin suggest the need for proactive planning and adaptation strategies, and warrant concern for similar melt-sourced Central Asian watersheds.”

You can read about this challenging situation here.

The Naryn river in Kyrgyzstan (Source: Nurdjen/Creative Commons).
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