The selectivity of the Swedish grid and 120 mm square mesh panels in the Scottish Nephrops trawl fishery

Abstract

Two sets of trials were conducted, on the west and east coasts of Scotland, to estimate the selectivity of an 80 mm diamond mesh codend fitted with (i) a 35 mm Swedish grid, (ii) a 120 mm square mesh panel (SMP) at 6–9 m from the codline and (iii) a 120 mm SMP at 12–15 m from the codline. The main results can be summarised as follows: • the Swedish grid gear retained all Nephrops < 40 mm carapace length and between 75 and 90% of Nephrops ≥ 41 mm; • the SMP gears retained between 70 and 88% of Nephrops below about 37 mm and all Nephrops ≥ 40 mm; • the grid gear retained fewer whitefish than the SMP gears. No cod > 34 cm, haddock > 35 cm, whiting > 38 cm and hake > 41 cm were retained by the grid gear; • and the position of the SMP had no significant effect on the retention of Nephrops, cod, haddock, or whiting.