by Jen Goldberg - GhostNets Australia

As part of an effort to better understand the movements and impacts of ghost nets, or lost fishing nets, GhostNets Australia (GNA) has embarked on a program to track these destructive nets off the coast of the Northern Territory.

As GNA Project Officer Jen Goldberg outlines, “We’ve all been working to reduce the number of ghost nets for quite a while now, and the more work we do, the more we realise that the problem isn’t going away.

“We are still searching for the answers to some pretty important questions, such as why do some regions receive more nets than others? How long does a ghost net stay in the water before it is beached? How does a ghost net move? How many animals are entrapped by a ghost net? Hopefully this satellite project will help us answer some of those questions.”

The project initiated by NT Project Officer Scott Morrison, uses Micro star prototype drift net trackers developed by U.S. company ‘Pacific Gyre’ (www.pacificgyre.com). GNA aims to track the nets by satellite.

Pacific Gyre specialise in the design and manufacture of drifting buoys and marker buoys in order to track currents and collect remote, environmental data.

In order to launch the trackers, GNA sought assistance from commercial fishing operators Bruce and Juanita Davey of the fishing vessel ‘FV Wildcard’.

The FV Wildcard has been an active campaigner against ghost nets and their impacts, and has frequently removed large ghost nets from north Australian waters.

On 2 February 2012, Bruce and Juanita encountered a net on a large reef system, one mile east of Marchinbar Island, the most north easterly point of the Northern Territory.

Bruce said, "This appears to be a relatively new net in very good condition with no marine growth attached and no marine mammals or other life in the net.
 
"It was a particularly challenging net salvage in extreme weather conditions, given we have had persistent gale and strong wind warnings the past seven to ten days from Darwin to Groote Eylandt.
 
"As the net was a moderately large gill net weighing around 100 to 150 kilograms, we could not bring it aboard."
 
In line with Federal, State and Territory legislation marine hazard reporting requirements, FV Wildcard marked the net with a buoy and sent the details and location to NT Marine Safety Branch and the Australian Maritime Safety Authority in Darwin and Canberra, so that it could be reported as a hazard to other mariners.

As this buoy is a drift net tracker, GNA can track real time locations of the ghost net via a dedicated website.

By satellite tracking the net, it will be possible to accurately locate it if it ever reaches the Australian mainland and Ranger groups working with GNA around the Gulf of Carpentaria may be able to examine the net for entangled wildlife before permanently disposing of it.

Alternatively, if the net remains at sea, the crew of the FV Wildcard may be able to regularly inspect the net for trapped animals while conducting commercial operations in the region. 

In partnership with NT Fisheries, and using information gained from routine Coast watch flights across the Gulf of Carpentaria and the Torres straits, GNA plans to pass on further reports of marine hazards to FV Wildcard while on its return journey to Cairns.

With assistance from NT fisheries and the Australian Customs and Border Protection, it is hoped that Bruce and Juanita Davey will be able to deploy two more drift net trackers.

The information gained from the drift net tracker deployment will complement GNA project partners CSIRO in their work computer modelling of sea current and net movement.

The Micro star prototype drift net trackers are designed to survive several months at sea and have a battery life of up to two years.

GNA hopes to provide regular updated maps of the nets progress and any findings that are made. These will be available on the GNA website under ‘latest news’ on the home page. 

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