A risk assessment of the sustainability of the harvest of beluga (Delphinapterus leucas (Pallas 1776)) in West Greenland

Abstract

Abstract Risk assessments to assess the efficiency of management procedures to regulate removals of marine mammals have rarely been conducted. Using Bayesian methods, we conducted a risk assessment on a harvested beluga population off West Greenland. The population size in recent years was estimated to be 22% of the size in 1954. Results indicate that current catches are unsustainable and that continuation of this situation represents a 90% probability that the population will become extinct in 20 years. The analyses suggest that the harvest should be reduced to no more than 130 animals. Constant catch quotas represent a greater risk of depletion compared with catch limits that are a function of harvest rate and population size. An alternative gradual reduction schedule is proposed as a viable strategy, reducing the harvest in 5 years and adjusting the subsequent quota using a harvest rate of 0.5 of Rmax, with updates in the abundance. This analysis is presented as an alternative for cases where an immediate catch reduction is desirable but not feasible for marine mammal populations that appear vulnerable or in danger and where catch and abundance data are available.