Fisheries is an important socio-economic contribution to the coastal fishing communities of Vietnam. Unfortunately, inshore natural resources have decreased in recent years. This decline has been largely attributed to overfishing and using a fishing gear with poor size selectivity. This paper estimated size selectivity curves for 8 important economic species using a covered codend attached to the codend of a commercial inshore trawl in Quang Ninh province, Vietnam. Results showed that sublegal-sized individuals accounted for a high proportion of the catch, ranging between 29.22 and 46.69%. The lengths at 50% retention (${\mathit{l}}_{50}$) were below minimum landing sizes (MLS) for all species caught, except conger eel (Muraenesox cinereus). Our study provides important scientific information for the fishery management in the studied area.

渔业是越南沿海渔业社区的重要社会经济贡献。不幸的是，近海自然资源近年来有所减少。这种下降主要归因于过度捕捞和使用尺寸选择性差的渔具。本文使用附在越南广宁省商业近海拖网编码器上的覆盖编码器估算了 8 种重要经济物种的尺寸选择性曲线。结果显示，未达到法定标准的个体占渔获量的比例很高，介于 29.22% 和 46.69% 之间。50% 保留时的长度 (${\mathit{升}}_{50}$) 低于所有捕获物种的最小上岸规格 (MLS)，但海鳗 ( Muraenesox cinereus )除外。我们的研究为研究区的渔业管理提供了重要的科学信息。