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Individual study: Effects of mesh size and escape gaps on discarding in an Australian giant mud crab (Scylla serrata) trap fishery

Published source details

Broadhurst M.K., Butcher P.A. & Cullis B.R. (2014) Effects of mesh size and escape gaps on discarding in an Australian giant mud crab (Scylla serrata) trap fishery. PLoS ONE, 9, e106414


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Fit one or more soft, semi-rigid, or rigid grids or frames on pots and traps Subtidal Benthic Invertebrate Conservation

A replicated, controlled study (date unspecified but appears to be 2012) in a muddy and sandy area in the Corindi River system, eastern Australia (Broadhurst et al. 2014) found that traps used to catch giant mud crabs Scylla serrata appeared to catch fewer undersized mud crabs when fitted with escape frame, compared to conventional traps without escape frames. The proportion of undersized crabs caught in traps fitted with frames appeared lower (2%) compared to conventional traps (29%; results not tested for statistical significance). In addition, the number of wounded mud crabs (undersized and commercial size) was statistically similar in traps with escape frames (0.06 crabs/trap) and conventional traps (0.13 crabs/trap). Conventional traps have four 300 × 200 mm funnel entrances but no escape frames. Conventional traps were modified by fitting two 46 × 120 mm escape frames. Seven modified traps and seven conventional traps were tested during 20 deployments. All traps were baited with sea mullet Mugil cephalus. Traps were recovered after 24 hours, and all catch identified, counted, and any wounds assessed.

(Summarised by Anaëlle Lemasson)

Fit one or more soft, semi-rigid, or rigid grids or frames and increase the mesh size of pots and traps Subtidal Benthic Invertebrate Conservation

A replicated, controlled study (date unspecified but appears to be 2012) in a muddy and sandy area in the Corindi River system, eastern Australia (Broadhurst et al. 2014) found that traps used to catch giant mud crabs Scylla serrata appeared to catch fewer unwanted undersized mud crabs when fitted with escape frames and designed with larger mesh size, compared to conventional traps. The proportion of undersized crabs caught in traps fitted with frames and designed with 101 mm mesh appeared lower (11%) compared to conventional traps without frames and of 51 mm mesh (29%; results not tested for statistical significance). In addition, the number of wounded mud crabs (undersized and commercial size) was statistically similar in traps with escape frames and larger mesh size (0.04 crabs/trap) and conventional traps (0.13 crabs/trap). Conventional traps have four 300 × 200 mm funnel entrances, no escape frames, and are designed with 51 mm mesh. Conventional traps were modified by fitting two 46 × 120 mm escape frames and increasing the mesh size to 101 mm. Seven modified traps and seven conventional traps were tested during 20 deployments. All traps were baited with sea mullet Mugil cephalus. Traps were recovered after 24 hours, and all catch identified, counted, and any wounds assessed.

(Summarised by Anaëlle Lemasson)