What if there were no fishing? North Atlantic right whale population trajectories without entanglement mortality

摘要

The North Atlantic right whale Eubalaena glacialis, one of the worlda??s rarest mammals, experienced an alarming level of mortality in 2017. The estimated abundance as of 2016 was 451 animals. After 20 yr of relatively steady but slow growth, the population has declined since 2010. Mortality and serious injury from entanglement in commercial fishing gear have had a significant impact on recovery. Despite legal requirements to reduce fishery-related mortality, little or no real progress has been made over the last 2 decades. Here I took a relatively simple approach to estimate what the population trajectory since 1990 might have been under 4 different scenarios of reduced entanglement mortality. Under the best-case scenarios, the population at the end of the time-series would have been 25-30% higher than observed at present. If the population had not experienced nearly 3 decades of increasing entanglement, it could have been much more resilient to a disaster year like 2017.