Proposed bycatch-reduction modifications of shrimp fyke nets used in South American lagoons

Abstract

Background. Shrimp fisheries using fyke nets have been associated with a massive acquisition of teleost fishes as bycatch, potentially resulting in the decimation of their stocks. Based on this assumption, the presently reported study intended to test an alternative modification of a commonly used fyke net, in order to minimize the impact of its low selectivity. Materials and methods. To evaluate the alternative design proposed in this work, a total of 44 sampling efforts, including 22 with a control gear (CG) and 22 with a modified gear (MG), were conducted at a subtropical coastal lagoon system located in southern Brazil. In all trials, the fyke nets were installed at the fishing area approximately at 18:00 h and removed approximately at 06:00 h. The duration of each trial was nearly 12 h, which was similar to the catching time preferred by local fishermen. Results. Bycatch (BC) was preponderant in both modalities but the results showed that MG presented a reduction by 66 percentage points in BC catches, being more selective than CG. Additionally, the non-parametric test showed no significant differences of shrimp catches between the fishing gears used (MG and CG). So, the tested bycatch reduction devices (BRD) reduced the bony fishes acquisition preserving the volume of the target catch. Conclusion. The vertical opening reduction due the adoption of guiding panel + fan upper panel contributed to bycatch reduction, being a consistent BRD to reduce the potential impacts of this fishing gear over the bony fishes stocks.

Keywords

• responsible fisheries
• shrimp
• bycatch reduction