increasing codend mesh size

to reduce discards of nephrops, haddock and whiting in a nephrops trawl

Target species:
Nephrops and mixed whitefish and flatfish species

Area, Vessel
41 twin trawl hauls took place in the west of Scotland on board the Ocean Trust PD787 during July 2014
Gear type:
twin trawl

Gear modification
The catches in a nephrops trawl with (i) 80mm diamond mesh codend of 4mm single PE twine (ii) 100mm diamond mesh codend of 5mm double PE twine (iii) 120mm diamond mesh codend of 5mm double PE twine are compared.


Results:
Increasing mesh size reduces discards of Nephrops, haddock and whiting. For Nephrops: in the 80mm mesh codend most selectivity occurs over the lower size range (< 38mm); in the 100mm codend some selectivity also occurs over 39-47mm size range; and in the 120mm codend selection occurs across the full length range.
Further information:
Drewery, J, et al., 2015. Effects of Codend Mesh Size and Twine Number on Nephrops Selectivity. Scottish Marine and Freshwater Science Vol 6 No 3. DOI: 10.7489/1552-1




Citation :
Drewery, J, et al. , 2017. increasing codend mesh size . In O’Neill, F.G. and Mutch, K. (Eds): Selectivity in Trawl Fishing Gears. Scottish Marine and Freshwater Science Vol 8 No 1.