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

North Atlantic right whales Eubalaena glacialis are most commonly observed along the eastern seaboard of America; however, their distribution and occupancy patterns have become less predictable in last decade. This study explored individual captured photographically from both dedicated opportunistic sources 2015 to 2019 Gulf St. Lawrence (GSL), an area previously understudied for whale presence. A total 187 individuals, including reproductive females, were identified all over this period. In years when more substantial survey effort occurred (2017-2019), similar numbers individuals sighted (mean = 133, SD 1.5), mark-recapture aerial surveys highly effective at capturing almost estimated region (2019: N 137, 95% CI 135-147). high rate inter-annual return was between 5 years, with animals seen previously. Capture rates indicated potential residencies as long mo, behaviors included feeding socializing. Individuals northern southern GSL, regions divided by a major shipping corridor. Analyses suggest that mostly moved than 9.1 km d -1 , although up 79.8 also calculated. The GSL is currently important habitat 40% Critically Endangered species, which underscores how crucial protection measures area.