Square-mesh codend length and selectivity in southeastern Australian stow nets

Two experiments (1. stow net set from small dory (4 m) and 2. a trawler was set in front of the mouth of the net to accelerate the flow of water) were conducted comparing three lengths of square-mesh codends (3, 2 and 1-m) made from 27-mm mesh with a conventional 34-mm diamond mesh design.  Overall, the square-mesh codend incrementally (from 1 to 3-m) selected the target school prawns across narrower selection ranges and for the most part selected prawns that had a larger size at 50% retention.  Fewer bycatch fish were also retained when the square-mesh codend was used.  In addition, there were differences between the two experiments and the impact of catch weight on the selectivity of school prawns.   The 2 and 3-m square-mesh codends retained proportionately more school prawns by both weight and number during the first experiment but less than the diamond and 1-m square-mesh designs during experiment 2, reflecting that more small school prawns were caught during the second experiment.