Cod-end mesh selectivity of stick stow net in north part of the South China sea

The cod -end mesh selectivity of double stake net was studied by using covered net method. Siganus oramin, Metapenaeus joyneri, Oxyurichthys microlepis and Argyrosomus argentatus were the main fishing targets in the area by the index of relative importance (IRI). Using the catch data of the four fishing targets, different mesh sizes selectivity curves of them were drawn by using Logistic curves as a selectivity model. Parameters of selectivity were estimated according to the maximum likelihood method. The results indicated that when the mesh size was 15 mm, there was no fish escape except Acetes; when the mesh size was 25 mm, the L50 of the four fishing targets was 53.17 mm, 50.16 mm, 61.05 mm and 26.37 mm, the SR of them was 13.43 mm, 17.50 mm, 41.88 mm and 12.78 mm, respectively; when the mesh size was 35 mm, the L50 of them was 80.72 mm, 77.12 mm, 86.97 mm and 68.68 mm, the SR of them was 19.48 mm, 39.08 mm, 28.20 mm and 13.17 mm, respectively. When the mesh size of the stake stow net increased, the L50 of the four fishing targets would enlarge, and their SR would enlarge expect O. microlepis.