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, 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.
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.
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 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.
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.
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…