Application of a Length-Based Stock Assessment Model for the Chub Mackerel (Scomber japonicus) in Korean Waters

• Published in: Ocean science journal 2022, 57(2), , pp.287-294
• Main Authors: Gim, Jinwoo, Hyun, Saang-Yoon
• Format: Article
• Language: English
• Subjects: Age structure; Aquatic Pollution; Earth and Environmental Science; Earth Sciences; Fish; Fish populations; Fishing; Fishing mortality; Least squares method; Marine & Freshwater Sciences; Marine fishes; Mortality; Natural mortality; Oceanography; Optimization; Scomber japonicus; Sensitivity analysis; Stock assessment; Waste Water Technology; Water Management; Water Pollution Control; 해양학
• ISSN: 1738-5261; 2005-7172
• DOI: 10.1007/s12601-022-00067-x

We modified Quinn’s size-based model for the assessment of chub mackerel ( Scomber japonicus ) stock in Korean waters, using annual data about body lengths (fork lengths), fishery catches, and catch-per-unit-effort. One of the strengths of Quinn’s size-based model is the construction of an imaginary age structure for a fish population, allowing the estimation of year- and age-based population sizes. Our modification was twofold. First, we applied a likelihood theory for numerical optimization, instead of the least squares method that Quinn et al. (1998) used. Second, we not only made point estimates of parameters, but also measured their uncertainties, using ADMB (automatic differentiation model builder) software. Estimates of annual biomass from 2001 to 2017 ranged from 1.01 × 10 6 to 2.15 × 10 6 MT, and estimates of annual fishing mortality from 1996 to 2017 ranged from 0.11 to 0.32 per year. Using a sensitivity analysis, we obtained the natural mortality of the stock, which was 0.1 per year.