Use a pulse trawl instead of a beam trawl

How is the evidence assessed?
  • Effectiveness
    41%
  • Certainty
    34%
  • Harms
    15%

Study locations

Key messages

  • One study examined the effects of using a pulse trawl instead of a beam trawl on subtidal benthic invertebrates. The study was in the North Sea (Netherlands).

 

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

  • Unwanted catch abundance (1 study): One replicated, controlled, study in the North Sea found that pulse trawls caught less unwanted invertebrate catch compared to traditional beam trawls, but the effects varied with species.

OTHER (1 STUDY)

  • Commercial catch abundance (1 study): One replicated, controlled, study in the North Sea found that pulse trawls reduced the volume of commercial catch by 19% compared to beam trawls.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. 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.

    Study and other actions tested
Please cite as:

Lemasson, A.J., Pettit, L.R., Smith, R.K. & Sutherland, W.J. (2020) Subtidal Benthic Invertebrate Conservation. Pages 635-732 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Subtidal Benthic Invertebrate Conservation

This Action forms part of the Action Synopsis:

Subtidal Benthic Invertebrate Conservation
Subtidal Benthic Invertebrate Conservation

Subtidal Benthic Invertebrate Conservation - Published 2020

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