Short vs long penaeid trawls: effects of side taper on engineering and catching performances

Published source details Broadhurst M.K., Sterling D.J. & Millar R.B. (2012) Short vs long penaeid trawls: effects of side taper on engineering and catching performances. Fisheries Research, 134-136, 73-81.
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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, paired study in 2011–2012 of sandy mud bottom in an river/estuary flowing into the Tasman Sea, Australia (Broadhurst et al. 2012) found that modifying the length and number of panels in the body of a prawn trawl net reduced the unwanted catch of one of four main fish species caught in shorter compared to longer trawls. Average catch rates of southern herring Herklotsichthys castelnaui were lower in shorter trawl designs than longer designs (short: 4 fish/ha, long: 1–2 fish/ha), irrespective of panel number. But there were no differences between trawl types for Ramsey's perchlet Ambassis marianus, narrow banded sole Synclidopus macleayanus or yellowfin bream Acanthopagrus australis (short: 1–7 fish/ha, long: 1–6 fish/ha). Numbers of target school prawns Metapenaeus macleayi were lower in shorter trawls (short: 1,107 ind/ha, long: 2,247 ind/ha). Sampling was conducted in December 2011 and January 2012 in the Clarence River, New South Wales, using a local prawn trawler. Four designs of trawl were tested (see original paper for gear specifications). All were identical except for their body length/side taper (short 35°, or long 25°) and the number of panels (two or four). Twenty paired deployments with each trawl design were completed. Codend catches were sorted and weighed by species. Data on the main target and non-target species were analysed.

(Summarised by: Natasha Taylor)