Potential for growth of the st.Lawrence (quebec, canada) beluga whale (delphinapterus leucas) population based on modelling

Abstract

Animals dying from natural causes in a well-defined and unexploited white whale stock were recovered over more than three years.The sample shows a probable bias against the youngest age classes, and increased mortality at an early adult age.Age-specific survival rates derived from this sample were combined to various schedules of birth and early life survival to model the population through Leslie matrices, and examine its potential for growth.Modelling shows that the proportion of grey animals is a useful index for evaluating population trends in the field.Current values of this index in the St.Lawrence suggest that the population is declining.Modelling also suggests that present knowledge of age-specific vital rates in Arctic beluga populations does not warrant annual exploitation rates above 2%.Conseil International pour l'Exploration de la Mer.All rights reserved. © 1988 Conseil International pour l'Exploration de la Mer.