Research Document - 2003/080

Molecular genetics of narwhal (Monodon monoceros) from Canada and West Greenland (1982-2001)

By B.G.E. de March, D. Tenkula, and L. D. Postma

Abstract

We examined the molecular genetics of 433 narwhals, collected between 1982 and 2001, from hunts in 12 Nunavut communities in Canada and 2 locations in west Greenland. Major sampling locations in Canada were Repulse Bay, Grise Fiord, Broughton Island, Pond Inlet, and Arctic Bay. Narwhals from Repulse Bay were significantly differentiated from most high Arctic locations for both microsatellite alleles and mitochondrial DNA. Narwhals hunted in Igloolik were weakly differentiated from several other locations and most resembled high Arctic, not Hudson Bay, narwhals. Narwhals from Grise Fiord resembled some Greenland locations most and were very weakly differentiated from those hunted in several other locations. Otherwise, no differences could be shown among high Arctic locations in Canada. Narwhals from the Uummannaq district in Greenland may be a stock that differs from narwhal sampled in most locations in Canada. Weak overall differentiation may be due interbreeding and because narwhals may originate from few recent ancestors. Results do not necessarily negate the existence of stocks that differ for the purposes of management. A study using organochlorine contaminants to discriminate narwhal stocks (de March and Stern 2003) more convincingly showed that different narwhals from several different hunting locations, namely Grise Fiord, Pond Inlet, Broughton Island, and Repulse Bay had different contaminant profiles. If sample sizes were increased, some comparisons would possibly have sufficient power to distinguish additional differences among stocks. However, we predict that even with larger samples sizes, considerable genetic overlap would exist between locations examined, and that year-to-year differences would continue to be the greatest source of statistical variation.

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