In plane sight: a mark-recapture analysis of North Atlantic right whales in the Gulf of St. Lawrence

• Published in: Endangered Species Research
• Main Authors: Crowe, Leah M., Brown, Moira W., Corkeron, Peter, Hamilton, Philip K., Ramp, Christian, Ratelle, Stephanie, Vanderlaan, Angelia S. M., Cole, Tim V. N.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Inter Research 2021
• Subjects: Aerial survey; Abundance estimate; Age-sex structure; Movement; Residency; Canada; Eubalaena glacialis; North Atlantic
• Online Access: https://hdl.handle.net/1912/28618

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Crowe, L. M., Brown, M. W., Corkeron, P. J., Hamilton, P. K., Ramp, C., Ratelle, S., Vanderlaan, A. S. M., & Cole, T. V. N. In plane sight: a mark-recapture analysis of North Atlantic right whales in the Gulf of St. Lawrence. Endangered Species Research, 46, (2021): 227–251, https://doi.org/10.3354/esr01156. North Atlantic right whales Eubalaena glacialis are most commonly observed along the eastern seaboard of North America; however, their distribution and occupancy patterns have become less predictable in the last decade. This study explored the individual right whales captured photographically from both dedicated and opportunistic sources from 2015 to 2019 in the Gulf of St. Lawrence (GSL), an area previously understudied for right whale presence. A total of 187 individuals, including reproductive females, were identified from all sources over this period. In years when more substantial survey effort occurred (2017-2019), similar numbers of individuals were sighted (mean = 133, SD = 1.5), and dedicated mark-recapture aerial surveys were highly effective at capturing almost all of the whales estimated in the region (2019: N = 137, 95% CI = 135-147). A high rate of inter-annual return was observed between all 5 study years, with 95% of the animals seen in 2019 sighted previously. Capture rates indicated potential residencies as long as 5 mo, and observed behaviors included feeding and socializing. Individuals were observed in the northern and southern GSL, regions divided by a major shipping corridor. Analyses suggest that individuals mostly moved less than 9.1 km d-1, although rates of up to 79.8 km d-1 were also calculated. The GSL is currently an important habitat for 40% of this Critically Endangered species, which underscores how crucial protection measures are in this area. Funding was provided by the Department of Fisheries and Oceans Canada, the ...