Line-transect estimation of abundance of narwhal (Monodon monoceros) in Scoresby Sund and adjacent waters

Abstract

An aerial line transect survey of narwhal (Monodon monoceros) abundance in Scoresby Sund and adjacent fjords in East Greenland was conducted in September 1983 and 1984. An effort of 1747 and 1973 linear kilometers resulted in 66 and 19 primary sightings of narwhal pods in 1983 and 1984. respectively. The mean pod size increased slightly but not significantly from 1.99 to 2.56 between the two years. The resulting estimates of abundance of narwhals (not corrected for submerged animals) were 300 (95% Cl 165- 533) and 102 (95~ Cl 36-276) in 1983 and 1984, respectively. These two estimates are not significantly different. The difference between the two estimates is most likely due to annual variation, perhaps in combination with the formation of new ice in 1984, which could have forced the narwhals out of the study area.