Selection efficiency of encircling grids in a herring pontoon trap

► We evaluate the selection efficiency of encircling grids in a herring pontoon trap. ► 54–72% of the undersized herring could be removed from the catch. ► This is a significant step towards a more sustainable herring fishery in the Baltic Sea. High bycatches of undersized herring constitute a major problem in the Baltic Sea herring trap fishery. In an attempt to reduce these bycatches, this field study evaluates the efficiency of rigid selection grids encircling a herring pontoon trap. The results show that 54–72% of the undersized herring were removed from the catch. The introduction of such grids would therefore represent a significant step towards a more efficient and sustainable herring fishery in the Baltic Sea.