Dolphin and Union

Genetic studies have shown the herd to be distinct from both Peary caribou, and from barren-ground caribou. The animals in this herd are slightly larger and darker than the Peary caribou.

The herd migrates between Victoria Island and the adjacent Arctic mainland twice a year, going to the mainland in the fall and back to the island in the spring. The crossing distance varies, depending on the routes taken, but is typically between 40 and 50 kilometres. Some members of the herd are sometimes also found on smaller islands near Victoria Island. 

The management plan for the herd says the largest risk to its future is the sea ice that the caribou use to migrate. That sea ice is changing as the region warms. New ice is forming more than ten days later in the fall than it did in the early 1980s. Icebreaking is also a concern, as vessel traffic in the region increases. Local Inuit say they’re seeing an increase in the numbers of drowned caribou from the herd, sometimes numbering in the hundreds. Some communities say that shipping in the strait crossed by the caribou should be restricted to the open water season.

Competition with muskoxen is identified by local people as a potential source of decline for this herd. They also mention the habitat destruction caused by an overabundance of geese in the area may be affecting the food available for caribou. Local people have also reported seeing more diseased caribou. Some new parasites have sprung up on the caribou’s range, such as caribou lungworm, a parasite not reported on Victoria Island until 2010.

Several communities hunt the caribou from this herd, but harvest levels are uncertain, so the level of risk from harvesting is also uncertain. However, the latest survey report on the caribou by the Government of Nunavut said, "Harvest appeared to be a significant source of mortality for DU caribou from 2015 to 2019, with 14 of 43 mortalities of collared caribou having occurred due to harvesting." In September 2020, the Government of Nunavut set a "total allowable harvest" level for local communities at 42 animals. Ulukhaktok, a small Northest Territories community on the west coast of Victoria Island, has implemented a voluntary maximum harvest of 50 Dolphin and Union caribou per year and a voluntary closure in the spring to allow pregnant cows to migrate and calve.