The cosmos grid: A new design for reducing by-catch in the Nordic shrimp fishery

This paper presents the results of experiments aimed to improve the selectivity of the Nordic shrimp (Pandalus borealis) fishery, while also minimizing losses and increasing escapement of round fish. A new grid design, known as the Cosmos grid, was directly compared with the legally accepted HDPE grids on a research vessel and on a commercial vessel. The results showed that the rates of fish by-catch from the research vessel were up to three times higher than from the commercial one, a situation that was mainly explained by the differences in the vessel's towing speeds. Likewise, significant differences were observed in the water flows of the two grids. The 15% stronger flow registered in the Cosmos grid did not seem to influence the levels of by-catch (up to 40 kg/h for the two grids); however, it did provoke a reduction in the loss of shrimp of bigger length classes. In this context, the loss of shrimps was found to be non-size dependent. Selectivity curves appeared to be similar between the Cosmos and the HDPE grids, and did not significantly differ from the ones obtained in earlier experiments.