Research Document 2020/063

North Atlantic right whale abundance, demography and residency in the southern Gulf of St. Lawrence derived from directed aerial surveys

By Cole, T.V.N., Crowe, L.M., Corkeron, P.J., and Vanderlaan, A.S.M.

Abstract

During summer 2015, 2017 and 2018, we used aerial photo-identification to obtain estimates of stock size, abundance and residency time of North Atlantic right whales (Eubalaena glacialis) in the southern Gulf of St. Lawrence (GSL). Flights were made on four days in 2015, 15 days in 2017 and 26 days in 2018. Preliminary matching to the North Atlantic Right Whale Catalog identified a total of 153 individuals, of which 144 were matched to cataloged individuals and of the nine that were not, four were calves from the previous year. The proportions of sex and age classes we saw in the GSL did not differ substantially from the North Atlantic population as a whole. Based on recognized individuals of known sex, adult males comprised 48.6–55.9% of the individuals seen each year, adult females 23.5–28.2%, juvenile males 8.4–12.4%, and juvenile females 4.6–9.5%. Mark-recapture techniques applied to the photographic capture of individuals in the study area during 2017 and 2018 resulted in abundance estimates of 111 and 132 whales, respectively, with few individuals undetected and apparent extended residency of individuals.

Research Document 2020/063 (PDF, 000 KB)

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