Project number: 2011-209
Project Status:
Completed
Budget expenditure: $194,021.00
Principal Investigator: Jonathan Binns
Organisation: University of Tasmania (UTAS)
Project start/end date: 4 Sep 2011 - 17 Sep 2013
Contact:
FRDC
SPECIES

Need

Energy efficiency is a vital issue for Australian Fisheries with the prawn trawling industry being marginally profitable given present fuel prices. Further increases in fuel prices will cause many prawn trawling operators to become commercially unviable. For prawn trawling operations, 60% of the fuel consumed is whilst trawling (FRDC 2006/229), and the netting of the trawls is responsible for 60-80% of the towing drag (FRDC 2005/239). The results of previous and on-going projects show that prawn gear modification possesses significant potential for drag reduction.

Equally, it is important that prawn trawls produce “clean” catches with as little by-catch and benthic impact as possible. Devices to reduce by-catch and adverse benthic impact can however result in increased drag. Innovative design changes can therefore have conflicting outcomes. Resolution of this conflict, to establish trawl design principles that produce high performance with respect to flying shape and environmental impact is crucial to the future of the prawn trawling industry and is the challenge of the proposed project. The fundamental knowledge and methodologies established for prawn-trawling nets will also directly assist the process of optimising net drag for fish trawls to a significant extent.

Objectives

1. Systematically breakdown and understand the technical issues connected with the generation of drag by prawn trawls, and the competing needs of industry, to establish practical trawl improvements based on existing and new trawl design principles.
2. To optimise the shape and netting characteristics of a novel trawl design for prawn trawling with respect to lower drag and minimum environmental impact.
3. To predict the drag of prawn trawls based on net plan parameters and towing speed, accounting for twine orientation and the operational shape of the trawl.