The effects of trawl configuration on the size and composition of catches using benthic prawn trawls off the coast of New South Wales, Australia

Published source details Andrew N.L., Graham K.J., Kennelly S.J. & Broadhurst M.K. (1991) The effects of trawl configuration on the size and composition of catches using benthic prawn trawls off the coast of New South Wales, Australia. ICES Journal of Marine Science, 48, 201-209.
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This study is summarised as evidence for the following.

	Action	Category
	Modify the design or configuration of trawl gear (mixed measures) Action Link

Modify the design or configuration of trawl gear (mixed measures)

A replicated study in 1989 in an area of seabed in the South Pacific Ocean off New South Wales, Australia (Andrew et al. 1991) found that modifying the configuration (wire length and single or triple trawls) of four prawn trawl nets resulted in mixed effects on the reduction of non-target catches of red spot whiting Sillago bassensis and sand flathead Platycephalus caeruleopuncta. Overall catch rates of red spot whiting and sand flathead were similar for three of the four configurations (whiting, single/7 m: 2.4, single/40 m: 3.9, triple: 4.3 fish/ha; flathead, single/7 m: 1.7, single/40 m: 3.0, triple: 2.0 fish/ha) and higher in single trawls with 140 m wires/bridles (whiting: 13.8 fish/ha, flathead: 6.1 fish/ha). However, average fish length was greater in single trawls with 140 m bridles for both species (red spot whiting: 17.9 cm, sand flathead: 33.5 cm) compared to any other single trawls (whiting: 17.3–17.4 cm, flathead: 31.9–32.5 cm) and the triple trawl (whiting: 16.6 cm, flathead: 32.4 cm). In addition, the total weight of non-target catch (fish and invertebrates combined) was not statistically different between single- and triple net trawls (single, 7 m: 15 kg/ha, 40 m: 19 kg/ha, 140 m: 23 kg/ha; triple: 13 kg/ha), as were catches of target prawns Penaidae and shovelnose lobster Ibacus spp. (see paper for data). Replicate trawl deployments (30 min, 2.8 knots) were conducted with four trawl designs (single trawls with 7 m, 40 m or 140 m bridles, or triple rigged trawls) in December 1989 in 35–40 m depth. Full details of trawl designs are provided in the original study.

(Summarised by: Leo Clarke)