Population growth of northern anchovy and Pacific sardine using stage-specific matrix models

Abstract

The Lefkovitch matrix was applied to the northern anchovy Engraulis mordax and the Pacific sardine Sardinops sagax to determine which vital rates in the life history have the most effect on population growth. Three vital rates considered are the daily stage-specific instantaneous mortality rate, stage duration and daily age-specific fecundity per female. A population with individuals that grow at varying rates is shown to be more likely to increase. The models indicate that growth rates are important determinants of population growth and recruitment and it is likely that growth and mortality rates are linked. -from Authors