宽口涡螺是毛里塔尼亚底拖网渔业中常见兼捕种类,网具中加装刚性分隔栅可分离宽口涡螺,提高渔获物品质、提升捕捞效率.为探究不同栅型(横栅、竖栅、圆栅)和布设角度(30°、45°、60°)对宽口涡螺的分隔性能的差异,利用 3D打印技术制作了宽口涡螺模型,在水槽中进行了捕捞模拟试验,利用分隔效率模型对数据进行拟合,结果表明:(1)圆栅具有最大的个数分隔率,分隔效果最好,其次为竖栅、横栅;(2)随着角度增大,选择率SR增大,L50 减小;接触概率SR′减小,L′50 增大;(3)分隔效率受选择率与接触概率共同影响,角度越大,分隔效率越高.研究结果可为分隔栅的设计优化提供理论依据.
Cymbium pepo is a by-catch species in bottom trawl fishery in Mauritania.The sorting grid rigged in beam trawls can effectively separate snails,improving the quality of catches and enhancing the fish ing efficiency.In order to analyze the separation performance of different grid types(transverse grid,vertical grid,circular grid)and layout angles(30°,45°,60°).Snails'model was made using 3D printing technology,The fishing simulation test was conducted in the flume,the separation efficiency model was used to fit the data,The main results are as follows:(1)The circular grid has the largest number separation rate,and the separation effect is the best,followed by vertical grid and horizontal grid;(2)As the angle increases,the selectivity parameters SR in-creases and L50 decreases.The change trend of contact probability parameters is opposite to the selectivity pa-rameters.This study can provide a theoretical basis for the design and optimization of sorting grid.