Jiahang Wei

Sebastes schlegelii is a commercially significant species in the northern Yellow Sea. Recently, Sebastes schlegelii has shown a reduced stock density and a shift toward smaller body sizes in the northern Yellow Sea area off Liaoning Province. To comprehend the population dynamics and to formulate management tactics, we established a mathematical formula describing the length–weight relationship, as well as the corresponding growth equations for the body length and body weight. The biomass of Sebastes schlegelii in the northern Yellow Sea area off Liaoning Province was evaluated using biological survey data from 2019 to 2022. The findings reveal that the length–weight formula is expressed as W = 4.98 × 10⁻⁵L^2.8878 (R² = 0.9108), with L_∞ = 407.6 mm, W_∞ = 1717.04 g, K = 0.21 a⁻¹, and t₀ = −0.65 a. The critical age was 3.34 years, and the stock biomass was 13,141.35 tonnes. The current exploitation rate of this resource is below the maximum yield, indicating sustainable utilization. A fishing closure period from April to June is considered suitable. A minimum landing size of 240.48 mm is recommended for Sebastes schlegelii.

This study investigated the population dynamics of Cynoglossus gracilis in the offshore waters of Liaoning Province, China, to support sustainable fisheries management. Biological samples were collected from five major fishing ports between March and November 2024. Population dynamics were assessed based on growth, mortality, and exploitation parameters, and four seasonal fishing closure scenarios were evaluated using egg production per recruit (EPR) and spawning biomass per recruit (SBR) models. The estimated exploitation rate (E = 0.53) indicated that the stock was experiencing relatively high fishing pressure but remained close to the sustainable exploitation reference level. Yield-per-recruit analysis suggested that increasing the minimum catchable size could improve resource utilization efficiency. Among the evaluated closure scenarios, the April–September closure provided the greatest conservation benefit by enhancing reproductive potential and protecting spawning stock biomass. These findings provide valuable insights for optimizing harvest regulations and seasonal closure strategies, contributing to the sustainable management of Cynoglossus gracilis resources in the offshore waters of Liaoning Province.