Optimizing Square Mesh Panel Placement in Dolnets to Reduce Juvenile Bycatch

Abstract

Field experiments were conducted from April, 2024 to March, 2025 at Karanja in Raigad district using a 55 m dolnet to identify the most effective square mesh panel placement for enhancing juvenile escapement, reducing bycatch, promoting sustainable fisheries management, minimizing economic losses, and ensuring operational feasibility. The dolnets were fitted with 40 mm square mesh panels installed at four positions: (A) upper panel adjacent to the codend, (B) upper panel 5 m ahead of the codend, (C) lower panel 5 m ahead of the codend, and (D) lower panel adjacent to the codend. A total of 60 standardized hauls were carried out, comprising 15 hauls for each configuration, to evaluate the juvenile catch of Harpadon nehereus. Statistical analysis revealed significant differences in escapement among the configurations, with F=173.38 and p<0.001. The maximum escapement was recorded in the upper panel positioned 5 m ahead of the codend, with a mean value of 7.72±0.49, whereas the lower panel positioned 5 m ahead of the codend showed the lowest escapement, with a mean value of 3.63±0.29. The findings demonstrated that strategic placement of the square mesh panel on the upper panel 5 m ahead of the codend significantly improved juvenile escapement without compromising commercial catch.