A spatially explicit estimate of the prewhaling abundance of the endangered North Atlantic right whale

• Published in: Conservation Biology
• Main Authors: Monsarrat, Sophie, Pennino, Maria Grazia, Smith, Tim D, Reeves, Randall R, Meynard, Christine N, Kaplan, David M, Rodrigues, Ana S L
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell 2016
• Subjects: Eubalaena; caza de ballenas; feeding grounds; generalized additive modeling; historical baseline; línea base histórica; modelado aditivo generalizado; population size; tamaño de población; whaling; áreas de alimentación; Ballenas; Morse; Norwegian Sea; Pacific; Eubalaena glacialis; Eubalaena japonica; Newfoundland; North Atlantic; North Atlantic right whale; morse
• Online Access: http://hdl.handle.net/10261/348377; https://doi.org/10.1111/cobi.12664; https://api.elsevier.com/content/abstract/scopus_id/85027951923

The North Atlantic right whale (NARW) (Eubalaena glacialis) is one of the world's most threatened whales. It came close to extinction after nearly a millennium of exploitation and currently persists as a population of only approximately 500 individuals. Setting appropriate conservation targets for this species requires an understanding of its historical population size, as a baseline for measuring levels of depletion and progress toward recovery. This is made difficult by the scarcity of records over this species' long whaling history. We sought to estimate the preexploitation population size of the North Atlantic right whale and understand how this species was distributed across its range. We used a spatially explicit data set on historical catches of North Pacific right whales (NPRWs) (Eubalaena japonica) to model the relationship between right whale relative density and the environment during the summer feeding season. Assuming the 2 right whale species select similar environments, we projected this model to the North Atlantic to predict how the relative abundance of NARWs varied across their range. We calibrated these relative abundances with estimates of the NPRW total prewhaling population size to obtain high and low estimates for the overall NARW population size prior to exploitation. The model predicted 9,075-21,328 right whales in the North Atlantic. The current NARW population is thus <6% of the historical North Atlantic carrying capacity and has enormous potential for recovery. According to the model, in June-September NARWs concentrated in 2 main feeding areas: east of the Grand Banks of Newfoundland and in the Norwegian Sea. These 2 areas may become important in the future as feeding grounds and may already be used more regularly by this endangered species than is thought. This analysis was funded by the MORSE project French National Research Agency, CEP&S 2011 - Project ANR-11-CEPL-006. It also benefited from discussions with members of the CESAB (Center for Synthesis and Analysis of ...