Breaking down abundance to understand conservation for small populations: A case study of North Atlantic right whales

The world is currently facing a biodiversity crisis and for many species, this is exacerbated by historic exploitation. Monitoring programs provide an integral tool to understand changes in abundance and the impact of threats informing conservation actions. However, measures of absolute abundance for management can be misleading, particularly when there is a biased sex ratio. Here we recommend focusing on the rate-limiting cohort for management actions using the case of North Atlantic right whales. The North Atlantic right whale has a male-biased sex ratio, with reproductively active females making up less than a fifth of the species. We highlight the importance of understanding and incorporating reproductive potential into management actions to provide species with the best chance of recovery.