Maturity at age of chub mackerels under different stock level in the northwestern Pacific Ocean

In this document, we analyzed the maturity at age of chub mackerel in the northwestern Pacific Ocean regarding the stock level. The timing of maturity was variable depending on the stock levels. The maturation length was consistent throughout the different stock levels. Since the growth rate is affected by density-dependence effect, the variation of timing to reach the length at maturity is also density-dependent. Since maturity at age is variable based on the density, we recommend utilization of density-dependent maturity at age in the Technical Working Group for the Chub Mackerel Stock Assessment.