为探究人工鱼礁区单片刺网对许氏平鲉(Sebastes schlegeli)和大泷六线鱼(Hexagrammos otakii)的选择性, 于 2021 年 10 月在荣成北部人工鱼礁区使用 4 种网目尺寸(40 mm、50 mm、60 mm、70 mm)的单片刺网进行选择性实验。在 SELECT 模型的架构下, 使用 Normal、Lognormal、Gamma、Bi-normal 模型进行选择性拟合, 根据赤池信息指数(AIC)和模型残差(MD)选择最佳拟合模型。结果表明: Lognormal 模型拟合效果最佳, 其 AIC 值和 MD 值均为最低值。根据 Lognormal 模型, 不同网目尺寸许氏平鲉的模型拟合长度分别为 114.23 mm、142.79 mm、 171.35 mm、199.90 mm; 大泷六线鱼的模型拟合长度分别为 129.67 mm、162.09 mm、194.51 mm、226.92 mm。许氏平鲉和大泷六线鱼的体长与最大剖面周长的线性关系分别为: G=0.2877L+0.7463(R² =0.6722), G=0.2468L– 3.8531(R² =0.6851)。选取 150 mm 作为许氏平鲉和大泷六线鱼的理论成熟体长(MBL)进行分析, 结合幼鱼留存比例, 发现网目尺寸为 60 mm 和 70 mm 的刺网能够保护人工鱼礁区许氏平鲉和大泷六线鱼的幼鱼资源。研究结果可为人工鱼礁区渔业资源的管理和养护提供参考。

Black rockfish (Sebastes schlegelii) and fat greenling (Hexagrammos otakii) are important commercial species in the rocky areas of China. However, in recent years, their resources have declined dramatically due to overfishing. The construction of marine ranching and artificial reefs is undergoing rapid development in China in an attempt to restore fishery resources and the ecological environment and has achieved promising results. Despite an increase in the scale of the artificial reefs and the abundance of fishery resources, the strategy by which fish are captured in the most reasonable and efficient manner in artificial reef areas is yet to be established. At present, the main methods for catching black rockfish and fat greenling include traps, hooks, and gillnets. Traps are characterized by poor size selectivity, whereas hooks have a low catch efficiency. By contrast, gillnets are widely used in coastal fisheries because of their simplicity of operation and suitability for complex bottom conditions. However, due to the small mesh size of gillnets, large numbers of juveniles are often captured. To address this issue, in this study, gillnets with four different mesh sizes (40 mm, 50 mm, 60, and 70 mm) were tested for the capture of black rockfish and fat greenling during sea trials in the artificial reef areas of Beibu Bay, Rongcheng in October 2021. A total of 340 specimens of black rockfish and 415 specimens of fat greenling were caught. The total lengths of black rockfish and fat greenling ranged from 70 to 250 mm and 80 to 250 mm, respectively. Four different selectivity models (normal, lognormal, gamma, and bi-normal) of the SELECT method were fitted to the data sets. The lognormal model provided the best fit for these two species, with the lowest deviance and AIC value. The estimated modal lengths were 114.23 mm, 142.79 mm, 171.35 mm, and 199.90 mm for black rockfish and 129.67 mm, 162.09 mm, 194.51 mm, and 226.92 mm for fat greenling for the corresponding mesh sizes of 40, 50, 60, and 70 mm, respectively. The theoretical mature body length (MBL) of black rockfish and fat greenling was set at 150 mm for analysis. The proportion of juveniles captured decreased with an increasing mesh size. These results indicate that 70 mm and 70 mm are suitable for the capture of black rockfish and fat greenling while protecting juvenile resources in artificial reef areas.

S972

山东近海渔业资源调查与监测项目(37000022P11000111802T)