Project number: 2016-058
Project Status:
Budget expenditure: $113,468.11
Principal Investigator: Charlie Huveneers
Organisation: Flinders University
Project start/end date: 31 Jan 2018 - 30 Jan 2019


The Northern Prawn Fishery (NPF) is the largest Australian prawn fishery and the most valuable Commonwealth managed fishery. Annual gross value of production of the fishery was valued at $115.2 million in 2014. In recent decades, the incidental take of bycatch species has become an important issue in trawl fisheries worldwide. Impacts of fishing activities on the marine environment, including bycatch interactions are heavily scrutinised by organisations assessing the sustainability of fisheries such as the MSC. Various Threatened, Endangered and Protected (TEP) species are still regularly caught by the fishery, including sawfishes. All four sawfish species caught within the NPF are listed on the Convention on International Trade in Endangered Species (CITES) Appendix I and the Convention of Migratory Species (CMS) Appendices I & II. Within Australia, three species are listed as Vulnerable, and all four species are listed as Migratory on the EPBC Act 1999.

Sawfishes are among the most threatened family of marine fishes and the most threatened family of cartilaginous fishes (Dulvy et al 2014). Incidental capture, particularly in trawls and gillnets, is the primary threat to sawfishes (Harrison and Duly 2014). Based on a risk assessment of the bycatch species in the NPF, all sawfishes have been identified as ‘at risk’ to trawling and least likely to be sustainable from prawn trawl fishing. A bycatch sustainability assessment also showed little change in catches of sawfishes as a result of the introduction of TEDs into the commercial fleet. The threatened status of sawfishes, vulnerability to fisheries, ongoing catches, and the inefficiency of current bycatch reduction devices to reduce sawfish bycatch suggest an urgent need for the development of new bycatch reduction devices to minimise interactions with fishing gear. This will also have the benefit of improving crew safety on the vessels as the removal of sawfish entangled in the nets is quite dangerous.


1. Assess whether sawfish behaviourally respond to electric fields as measured by reaction from a stationary position
2. Compare sawfish behavioural response across three fields of different characteristics


Author: Charlie Huveneers

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This project tests the effect of electric fields on sawfish behaviour, to determine if a strong electric field can overwhelm their electrosensory system and dissuade them from approaching its source and/or elicit a fleeing behaviour. Sawfish clearly sensed and reacted to all electric fields tested, none of the waveforms used could repel from distances likely to be sufficient to deter sawfish from entering trawl nets. This means that the currently available devices that produce electric fields are unlikely to be useful to reduce sawfish bycatch in prawn trawlers.

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