Fit one or more mesh escape panels/windows and one or more soft, rigid or semi-rigid grids or frames to trawl nets

How is the evidence assessed?
  • Effectiveness
    65%
  • Certainty
    32%
  • Harms
    0%

Study locations

Key messages

  • One study examined the effects on subtidal benthic invertebrate populations of fitting one or more mesh escape panels/windows and one or more soft, rigid or semi-rigid grids or frames to trawl nets . The study was in the Gulf of Carpentaria (Australia).

 

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

  • Unwanted catch abundance (1 study): One replicated, paired, controlled study in Gulf of Carpentaria found that trawl nets fitted with an escape window and a grid reduced the total weight of small unwanted catch and caught fewer unwanted large sponges, compared to unmodified nets.

OTHER (1 STUDY)

  • Commercial catch abundance (1 study): One replicated, paired, controlled study in Carpentaria found that trawl nets fitted with an escape window and a grid reduced the catch of commercially targeted prawns, compared to unmodified nets.

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 2001 in areas of seabed in the Gulf of Carpentaria, northern Australia (Brewer et al. 2006) found that nets fitted with a mesh escape window (“bycatch reduction device”) and a grid (“turtle excluder device”), caught fewer large sponges and reduced the total weight of small unwanted catch (invertebrates and fish combined), compared to unmodified nets. Nets fitted with both escape window and grid caught 85% fewer large sponges and reduced the weight of small unwanted catch by 8%, compared to unmodified nets. The modified nets reduced the catch of commercially targeted prawns by 6%. The use of a “turtle excluder device” and a “bycatch reduction device” has been compulsory since 2000 in the Australian prawn fishery. Commercial vessels towed twin Florida Flyer prawn trawl nets from each side of the vessels in August–November 2001. Modified nets were fitted with both one of two designs of escape window (a “Bigeye” design or a square-mesh escape window) and one of 23 grid designs (rigid or semi-rigid frame with ≤120 mm bar spacing and an opening of ≥700 mm). A modified and an unmodified net were randomly assigned to either side of the vessel and towed simultaneously (324 modified nets examined for small unwanted catch, 150 for sponges; 703 unmodified nets for small unwanted catch, 339 for sponges). Total weights of small unwanted catch (<300 mm), commercially targeted prawns, and counts of sponges (>300 mm) were recorded. The combinations of various device designs were not compared. The “Bigeye” design was later removed from the Australian list of approved escape zone designs.

    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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