Where narwhals like to hang out
Narwhals – called “unicorns of the sea” because of the long tusks protruding from their heads – are some of the rarest whales in the world. Much is still unknown about these inhabitants of the cold Arctic waters. But a new study may shed a bit of light on the lives of the enigmatic marine mammals.
The research, presented February 12, 2018, at the Ocean Sciences Meeting in Portland, Oregon, found that narwhals prefer to congregate near glacier fjords with thick ice fronts, where icebergs break off infrequently. It appears narwhals prefer the freshwater coming off still, serene glaciers over the silt-filled runoff that gets discharged from very active glaciers.
Scientists have known narwhals spend time at the fronts of glaciers in Greenland during the summer, which are hotspots for marine mammals, seabirds and fishes. The researchers examined how narwhals behaved at the different glaciers and collected information about each glacier’s physical properties to create models of narwhal behavior and tease out the animals’ preferences.
Researcher Kristin Laidre is a marine biologist at the University of Washington’s Polar Science Center and the School of Aquatic and Fishery Sciences. She said in a statement:
Narwhals like slow-moving, big walls of ice where conditions are still and serene instead of a lot of runoff and disturbance.
The researchers aren’t sure why the narwhals prefer these glaciers. They think the freshwater could shock small marine critters that are food for fish, which narwhals eat. Narwhals are also close relatives of beluga whales, which also seek out freshwater in summer to shed their skin, and it is possible there is something similar going on at the glacier front, Laidre said.
For the study, Laidre and her colleagues used data from 15 narwhals outfitted with recorders that tracked each animal’s movements over four years in the 1990s and 2000s in Greenland’s Melville Bay, where narwhals congregate in summer. They combined this data with information about glaciers in Melville Bay over the same time period.
The findings could help scientists understand a little more about the elusive narwhal and how these marine mammals might fare in a changing climate, according to the researchers. Laidre said:
Arctic marine mammals are really good indicators of climate change because they are very specialized. They are finely attuned to specific environmental conditions, so they are good indicator species for how the physical changes many scientists are documenting in the Arctic can reverberate throughout the ecosystem.
Bottom line: New research suggests that narwhals prefer to congregate near glacier fjords with thick ice fronts, where icebergs break off infrequently.