We tested six different codends (D1–D6; Figure 2 and Table 1). Codend D1 is the standard BACOMA codend used in the Baltic trawl fishery, defined in EU Regulation No. 686/2010. Codend D2 differed from D1 by a shorter square mesh panel (50% reduced length) positioned at the aft end of the codend. Thus, for codends D1 and D2, the square mesh panel overlapped the catch-accumulation zone. Codend D3 was similar to codend D2 except that the short square mesh panel was positioned closest to the extension piece. The distance from the square mesh panel to the codend’s binding strap was ca. 3 m, and so the square mesh panel did not overlap the catch-accumulation zone for codend D3. The last three codends, D4, D5, and D6, were identical with codend D3, except that they had devices mounted to the bottom panel of the codend underneath the square mesh panel. These were meant to guide cod upwards to the square mesh panel and stimulate their escape behaviour instead of allowing them to drift in the direction of the catch-accumulation zone. Codend D4 was mounted with a stimulation device s1, whereas codends D5 and D6 were mounted with stimulation devices s2 and s3, respectively.