Effects of jig location and soak time on catch rates of a novel fishing gear design of squid longline fisheries

The use of handline jigging with artificial light is typical for the nighttime harvesting of cephalopod species in Vietnam. However, this fishing method requires great manpower and consumes a large amount of fuel for the electric generator. Therefore, developing an alternative fishing gear is needed. In this study, fishing experiments were conducted along the coast of Khanh Hoa province to compare the catch rate and size selectivity of a novel fishing gear design - squid horizontal longline - at different jig locations in the water where jigs actually work and to determine how soak time affected the catch rate and size selectivity. Our results showed that the effect of the squid longline on catch rates and size distribution depended on jig height from the seabed and soak time. The squid longline fished at 3 m higher off the seabed produced significantly higher catch rates than those fished at 7 m higher off the seabed. More large individuals were also caught at a depth of 3 m from the seabed. The catch rate increased with soak time, but peaked at 5 h of soaking. The new fishing method reduced the fuel consumption and crewmember as much as 60% and 38%, respectively compared to the traditional fishing technique. This study shows that squid longlines can promisingly replace conventional handline jigging with artificial light in harvesting squid species, which provides socioeconomic and environmental benefits. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

The study found that the squid horizontal longline fishing gear had a significant impact on catch rates and size distribution at different jig locations and soak times, with the best results achieved at a height of 3 meters off the seabed. The new method reduced fuel consumption and crew size compared to traditional fishing techniques.