Hydrodynamic characteristics of the otter board in trawling: a review

Trawl fishery plays a crucial role in marine fisheries in China. The otter boards (or trawl doors) are important components of fishing gear used to maintain the horizontal expansion of the trawl net mouth, ensuring fishing efficiency. Previous studies have shown that the drag generated by otter boards accounts for approximately 20% to 30% of the total drag in a trawl system. Developing high-performance otter boards is therefore of significant importance for enhancing fishing efficiency, reducing carbon emissions, conserving energy, and promoting environmental sustainability. We have reviewed the hydrodynamic characteristics of numerous otter boards around the globe, which includes the main structural factors and their effects on the hydrodynamic characteristics of the otter boards. Moreover, the design requirements and technical methods of otter boards under different development concepts such as energy and labor savings and green ecology are also discussed, aiming to provide important theoretical references for the development of high-performance otter boards in Chinese trawl fishery.