MUFTI-2 acoustic towed body
Date2010s
Object number00055792
NameInstrument
MediumFiberglass, stainless steel, aluminium
DimensionsOverall: 800 × 2950 × 800 mm, 295 kg
Copyright© CSIRO
ClassificationsTools and equipment
Credit LineAustralian National Maritime Museum Collection Gift of CSIRO
DescriptionCSIRO's towed body allows for close range multi-frequency detection of various fish groupings. Its design and deployment improves upon the limitations of traditional ship hull mounted transducers. The MUFTI-2 (Multi Frequency Towed Instrument) tow body has the capability of detecting fish at the frequencies of 18kHz, 38kHz, and 120 kHz, and is embedded with technology to digitize signals and transmit data back to vessels as Ethernet packets. MUFTI-2's multi-frequency capability allows for very accurate fish species discrimination, leading to enhanced fisheries management.HistoryThe development of CSIRO's Towed Body was the result of a push for a more effective system for detecting differing fisheries in Australian waters. Fish groupings such as the Blue Grenadier and Orange Roughy cannot always be effectively detected with ship hull mounted transducers, or at all with single fish targets. Particular issues arise with attenuation losses due to surface bubbles, ship/flow noise and acoustic dead zones. Furthermore, to detect a single fish grouping the transducer must be less than 50-100m away.
Towed body technology allows for close operation to fish schools, and the detection of single fish targets utilizing four different frequencies: 18kHz, 38kHz, 70 kHz, and 120 kHz. Different frequencies can determine different species based on the fish shape or the swim bladder type. This leads to very accurate species discrimination and more accurate target species stock assessment leading to enhanced fisheries management. CSIRO's first acoustic tow body, the MUFTI-1 (Multi Frequency Towed Instrument), relied on the transmission of analogue signals up a tow cable to the shipboard transceivers. This led to problems with system noise, signal loss and difficult calibration issues.
CSIRO's second generation tow body, the MUFTI-2, was tested in the winter of 2004 on the west coast of Tasmania. Fitted with technology to digitize signals, this improved tow body could deliver these messages to a vessel as Ethernet packets using an embedded one multimode optical fibre. The MUFTI-2 proved effective when tested in the often challenging conditions of the Southern Ocean. Further features of the tow body included a multi-transducer capability, an independent data acquisition and power control system, and a 3000m Rochester/Tyco contra-wound galvanised steel armoured tow cable.
SignificanceCSIRO's towed body technology has made rapid advancements in the area of fishery detection and management. The MUFTI-2 improves upon traditional ship hull mounted transducer systems through its ability to operate at close range, and across various frequencies. This multi frequency capability allows for very accurate fish species discrimination, certain fish responsive to differing frequencies, leading to enhanced approaches to fishery management. The MUFTI-2 is further embedded with technology to digitize signals and transmit data back to vessels as Ethernet packets, a more efficient process than the analogue system used by the MUFTI-1.
