Use an otter trawl instead of a beam trawl

How is the evidence assessed?
  • Effectiveness
    50%
  • Certainty
    34%
  • Harms
    10%

Source countries

Key messages

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

 

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

  • Overall abundance (1 study): One replicated, paired, controlled study in the North Sea found that otter trawls caused similar mortality of invertebrates in the trawl tracks compared to beam trawls in sandy areas but lower mortality in silty areas.

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, paired, controlled study in 1992–1995 in four areas of sandy or silty seabed in the south-eastern North Sea, Netherlands and Germany (Bergman & Van Santbrink 2000) found that the effects of otter trawls compared to beam trawls on invertebrate mortality varied with the sediment type. Otter trawls caused similar mortality of invertebrates in the trawl tracks compared to beam trawls in sandy areas (otter: 0–41%: beam: 1–53%) but lower mortality in silty areas (otter: 1–65%: beam: 2–82%). In spring-summer 1992–1995 parallel strips (2,000 x 60 m, 300 m apart, number unspecified) in one sandy location and three silty locations were fished with either a commercially used beam trawl with tickler chains or an otter trawl. Prior to trawling, mega-invertebrates (>1 cm) and macro-invertebrates (> 1 mm) were counted from samples taken in each strip using a dredge and a sediment grab. After 24–48 h following trawling, all strips were sampled again using the same methods. Mortality (from trawling) of invertebrates present in the trawl tracks was calculated using the difference between the before and after-trawling abundances (assuming all animals killed by trawling had been eaten by predators).

    Study and other actions tested
Please cite as:

Lemasson, A.J., Pettit, L.R., Smith, R.K., and Sutherland, W.J. (2019) Subtidal Benthic Invertebrate Conservation: Global Evidence for the Effects of Interventions. Synopses of Conservation Evidence Series. University of Cambridge, 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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