Individual study: Catch comparison of flatfish pulse trawls and a tickler chain beam trawl
Van Marlen B., Wiegerinck J.A.M., van Os-Koomen E. & van Barneveld E. (2014) Catch comparison of flatfish pulse trawls and a tickler chain beam trawl. Fisheries Research, 151, 57-69
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Use a pulse trawl instead of a beam trawl
A replicated, controlled study in 2011 in sandy areas in the North Sea, Netherlands (Van Marlen et al. 2014) found that pulse trawls caught fewer unwanted invertebrates compared to traditional beam trawls, but the effects varied with species. Fewer unwanted invertebrates were caught when using pulse trawls compared to using beam trawls (pulse: 142 vs beam: 177 individuals/ha). However, when sorted by groups, pulse trawls caught fewer invertebrates living on the sediments (131 vs 175) but more living inside the sediment (11 vs 2), compared to beam trawls. In particular, pulse trawls caught fewer echinoderms (82 vs 113) and gastropods (sea snails; 0.0 vs 0.1), compared to the beam trawl, similar numbers of anthozoan (0.0 vs 0.1), bivalves (0.1 vs 0.2), cephalopods (0.1 vs 0.2), and crustaceans (60 vs 64). Pulse trawls also caught 57% less total discards (non-commercial unwanted catch of invertebrates and fish) by volume (0.25 vs 0.29 basket/ha). The pulse trawl reduced the volume of commercial catch by 19% compared to the traditional trawl (0.08 vs 0.1 basket/ha). Pulse (electrical) trawling was prohibited in European fisheries in 1998, but a system of derogations set up in 2006 has allowed the practice to continue, including experimental trials. Comparison trials were conducted in May 2011 with three vessels fishing side-by-side (two boats using pulse trawls, one using traditional flat-fish tickler chain beam trawls). Catches from 33 trawls/vessel were assessed. The total discard volume was measured. Invertebrate discards were identified and counted from one subsample of total catch/trawl (35 kg basket). As of 2019, the practice has been fully banned in European waters.
(Summarised by Anaëlle Lemasson & Laura Pettit)