Work

Size Selectivity of Square-Mesh Codends in Stownet for Coilia mystus in the South China Sea

Year: 2025

Type: article

Abstract: Stownet is one of the most important items of fishing gear for catching Coilia mystus in China’s coastal waters. To improve the selectivity of stownet for C. mystus, a series of selectivity experiments were conducted using the covered net method with 4 square-mesh codends of different mesh sizes of 25 mm, 30 mm, 35 mm, and 40 mm. The selectivity curves of C. mystus under different mesh sizes were fitted using the Logistic and Richards models, and the selectivity parameters were compared among codends. The results showed that the 50% selection length (L50) increased with mesh size, reaching 105.83 mm, 109.02 mm, 114.36 mm, and 116.66 mm, respectively. The proportion of juvenile C. mystus in the codends decreased correspondingly, indicating that larger mesh sizes improved the selectivity of the square-mesh codend. Based on the linear relationship between L50 and mesh size, the minimum mesh size for C. mystus was estimated to be 43.81 mm. Considering the management regulation of the minimum landing size (120 mm) for C. mystus, the L50 obtained for the 40 mm square-mesh was still below this standard, suggesting that the selectivity of the current codend requires further optimization to promote the sustainable utilization of C. mystus resources.

Source: Animals

DOI: 10.3390/ani15243571