biostudies-literatureSchleimer AFonds National de la Recherche Luxembourg4231-4244https://www.ebi.ac.uk/biostudies/studies/S-EPMC6468087biostudies-literatureUnknown9(7)Estimates of abundance and survivorship provide quantifiable measures to monitor populations and to define and understand their conservation status. This study investigated changes in abundance and survival rates of fin whales (<i>Balaenoptera physalus</i>) in the northern Gulf of St. Lawrence in the context of anthropogenic pressures and changing environmental conditions. A long-term data set, consisting of 35 years of photo-identification surveys and comprising more than 5,000 identifications of 507 individuals, formed the basis of this mark-recapture study. Based on model selection using corrected Akaike Information Criterion, the most parsimonious Cormack-Jolly-Seber model included a linear temporal trend in noncalf apparent survival rates with a sharp decline in the last 5 years of thEcology and evolutionDecline in abundance and apparent survival rates of fin whales (<i>Balaenoptera physalus</i>) in the northern Gulf of St. Lawrence.PMC6468087AFR/11256673Carpentier ARamp CPalsboll PJHammond PSSchleimer ASears RBerube MDelarue JfalseDecline in abundance and apparent survival rates of fin whales (<i>Balaenoptera physalus</i>) in the northern Gulf of St. Lawrence.Estimates of abundance and survivorship provide quantifiable measures to monitor populations and to define and understand their conservation status. This study investigated changes in abundance and survival rates of fin whales (<i>Balaenoptera physalus</i>) in the northern Gulf of St. Lawrence in the context of anthropogenic pressures and changing environmental conditions. A long-term data set, consisting of 35 years of photo-identification surveys and comprising more than 5,000 identifications of 507 individuals, formed the basis of this mark-recapture study. Based on model selection using corrected Akaike Information Criterion, the most parsimonious Cormack-Jolly-Seber model included a linear temporal trend in noncalf apparent survival rates with a sharp decline in the last 5 years of th2019-01-01T00:00:00Z2019 Apr2025-04-18T22:57:06.97Z2019-06-06T22:56:30ZS-EPMC64680873101600110.1002/ece3.5055