Install physical barriers to prevent trawling

How is the evidence assessed?
  • Effectiveness
    75%
  • Certainty
    32%
  • Harms
    0%

Study locations

Key messages

  • One study examined the effects of installing physical barriers to prevent trawling on subtidal benthic invertebrate populations. The study was in the Bay of Biscay (Spain).

 

COMMUNITY RESPONSE (1 STUDY)

  • Overall community composition (1 study): One before-and-after study in the Bay of Biscay found that one to four years after installing artificial reefs as physical barriers to prevent trawling invertebrate community composition changed.

POPULATION RESPONSE (1 STUDY)

  • Overall abundance (1 study): One before-and-after study in the Bay of Biscay found that one to four years after installing artificial reefs as physical barriers to prevent trawling overall invertebrate biomass increased.
  • Echinoderm abundance (1 study): One before-and-after study in the Bay of Biscay found that one to four years after installing artificial reefs as physical barriers to prevent trawling the biomass of sea urchins and starfish increased.
  • Molluscs abundance (1 study): One before-and-after study in the Bay of Biscay found that one to four years after installing artificial reefs as physical barriers to prevent trawling the biomass of gastropods (sea snails), of one species of cuttlefish, and of two species of octopus increased.

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 before-and-after study in 1998–2007 in one area of soft seabed in the Cantabrian Sea, southern Bay of Biscay, Spain (Serrano et al. 2011) found that one to four years after installing barriers to prevent illegal trawling the biomass of invertebrates increased, and species community composition changed. Total invertebrate biomass was higher after one (3 kg/ha) and four years (7 kg/ha), compared to before installation (0–1 kg/ha). There were increases in the biomass of sea urchins (before: 12; after: 3,150 g/ha), common octopus Octopus vulgaris (before: 222; after: 920 g/ha), starfish (before: 9; after: 78 g/ha), gastropods (before: 18; after: 50 g/ha), cuttlefish Sepia spp. (before: 56; after: 131 g/ha), and curled octopus Eledone cirrhosa (before: 9; after: 18 g/ha). Invertebrate community composition was different before and after deployment (results presented as graphical analyses). Bottom trawling in the area was prohibited at depths <100 m by local legislation, but illegal trawling was common. To prevent it, artificial reefs (groups of concrete blocks 2 km apart; numbers not specified) were deployed in 2003 at 80–85 m depth. One sampling station near each group of blocks (sandy seabed without blocks) was surveyed annually in October in 1998–2007 (survey methods not specified).

    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

What Works 2021 cover

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