연령구조모델의 MSY 계산에서 steepness와 자연사망률의 영향 분석

Abstract

In stock-recruitment relationship within an age-structured model, two parameters, steepness and natural mortality rate, are critically linked to Maximum Sustainable Yield (MSY). Steepness is defined as the ratio of the offspring from 20% of mature females to that from the entire mature female population in an unexploited condition. However, estimating these parameters has been challenging due to factors such as data scarcity and environmental influences. Despite developing various methods to estimate these parameters, scientists face substantial uncertainty in these estimations. This uncertainty underscores the need for research into how steepness and natural mortality rate influence MSY calculations. This study aimed to review the methods for estimating these parameters and to examine their impacts on the estimating of MSY and fishing mortality rate that attains MSY (FMSY) within the age-structured model. For illustrating the process, I used two data sets: the chub mackerel (Scomber japonicus) in the Korean waters and the yellowtail flounder (Limanda ferruginea) in the Northwest Atlantic. The study revealed that natural mortality rate significantly influences spawning stock biomass per recruit, yield per recruit, MSY and FMSY, while steepness affects MSY and FMSY. This research offer crucial insights into the effects of these parameters on MSY estimates, contributing valuable information for more accurate and sustainable fisheries management.