Scoping the Problem
In Australia ghost nets (discarded or abandoned fishing nets) are devastating our endangered marine life.
This is particularly the case in Australia’s far north in the Gulf of Carpentaria, which is one of the last remaining safe havens for endangered marine and coastal species, including six of the world’s seven marine turtle species, dugongs and sawfish. Sadly these turtles make up 80 percent of the marine life found caught in the nets.
GhostNets Australia has already facilitated the rescue of over 300 entrapped turtles and removal of 13,000 nets from our beaches and estuaries. But as our former Project Officer Jen Goldberg identified, “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?
- Is this rubbish Australian? If not, where does it come from?
- And who is responsible?
- How does a ghost net move?
- How many animals are entrapped by a ghost net? and
- What to do with all this rubbish”
To answer these questions GNA, in partnership with CSIRO, has been able to learn from the nets themselves many things, use computer modelling to map their fishing effort and track nets in situ using satellite tracking technology.
Explore the thumbnails below to understand the full complexity of the problem we face.
What is the Source of all this Rubbish?
Using the WWF Net Kit, analysis from the GNA data show that nets recognised as those employed by Australian fisheries are consistently below 10%. This poses the question as to where does the other 90% come from?
Additionally, the proportion of unidentified nets for the period of 2010-2012 has increased slightly from the previous period 2004-2009, indicating newer nets entering the system are not captured by the current resources available for net identification.
To understand more about the source of this rubbish we need to also understand
- the abundance and distribution (hotspots),
- the movement of the nets,
- the geographical origin,
- the types of fisheries that use the nets, and
- the stakeholders.
For a full account of all data results please email to request a copy of our 2012 Summary Report.
Waste Management
Our objective has always been to have an ocean free from ghost nets, but in the meantime we are left with the very real issue of what to do with the tonnes of net that wash ashore.
The disposal of rubbish in remote areas in Australia is extremely challenging, so the safe and environmentally sound disposal of tonnes of plastic net material is virtually impossible. In most instances ghost nets are bunt in situ or taken to local landfill where they are eventually buried. Environmentally neither is a good option, so we’ve been working hard to investigate others.
Given the nets are primarily plastic, we have explored many plastic recycling options including:
- supplying the nets as feedstock for the boilers in concrete factories,
- turning nets into carpets,
- creating composite plastic products (such as fence posts), and
- even returning the plastic into a type of diesel fuel.
Unfortunately none of these options are viable given the high transport costs to get the nets to centres in the south. Nor is buidling recycling centres in the north a viable option as the low population inthis remote part of Australia does not make such factories viable.
Satellite Technology
Using satellite technology we’ve been able to track several gill nets to help us understand more about the movements and devastating impacts of ghost nets.
The project was initiated by our Northern Territory Project Officer Scott Morrison, utilising Micro star prototype drift net trackers (developed by U.S. company Pacific Gyre) to track the nets by satellite. We’ve chosen to work with these trackers as they have a battery life of up to two years, are designed to survive several months at sea and include:
- drifting buoys, designed to track and follow the currents
- marker buoys, designed to remain in place to collect remote, environmental data.
To launch the first trackers we called on our partners Bruce and Juanita Davey, from the fishing vessel ‘FV Wildcard’. The Daveys are commercial fishing operators and active anti-ghost net campaigners, and we know they frequently remove nets from north Australian waters.
The Davey’s were on the look out for the first opportunity to launch the trackers and in early 2012 they encountered a large gill net on a reef system in the most north-easterly point of the Northern Territory. A closer inspection showed that the net was ideal for tracking. There was no marine growth or evidence of marine life in the net, indicating that the net was relatively net and in very good condition and could not be brought aboard given the net weighed in excess of 120 kg and the Daveys were experiencing extreme weather.
The Davey’s followed protocol and sent the details of the net and the precise location to the Northern Territory 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. The Daveys then marked the net with a drifting buoy, enabling us to track real time locations of the ghost net via the Pacific Gyre website.
Using satellite technology were then able to track the pathway of the net and when it reached Australian mainland our Rangers were able to easily locate it, examine the net for entangled wildlife before removing and permanently disposing of it from our beaches.
With assistance from Northern Territory Fisheries and the Australian Customs and Border Protection, we hope to provide the Davey accurate information about the location of other ghost nets so they can deploy more drift net trackers.
We are also pleased that we can share the information gained with our partners at the CSIRO who are currently modeling of sea current and net movement and we hope to provide regular updated maps of the nets progress and any findings that are made.
Our special thanks goes to Bruce and Juanita Davey for making this exciting project a reality.
Estimating the Biodiversity Impacts of Ghost Nets
We engaged in three research projects in partnership with CSIRO and UQ.
The first research developed an integrated analysis to make quantitative predictions of previously unknown high-risk areas for turtle entanglement in the Gulf of Carpentaria.
The second research project was via collaboration between the University of Queensland, Mapoon rangers and CSIRO. The project aimed to determine decay rate (half-life) of by-catch, particularly turtles and sharks in a ghost net suspended in the ocean.
The third research project evaluated which net was the ‘deadliest’.
Explore the thumbnails below to learn more about the biodiversity impacts of ghost nets.
Which fisheries are Responsible?
From our data (2012 Summary Report) we know that the most frequent type of net is from trawl fisheries (62.2%), followed by gill nets (14.4%) and the rest mostly undetermined.
We also now know that most of the nets originate from the Arafura Sea and that the Arafura Fishery is a very important fishery for Indonesia as it is the only part of Indonesian waters where trawling is not banned. The Arafura Sea is rich in nutrients, making it a prime fishing ground that attracts fishermen of all scales of fishing activity, from the subsistence fisher to extremely large ‘factory’ vessels. Many of these fisheries are unregulated making it difficult to understand exactly who is fishing in the region.
But who actually uses these nets? where do the fishermen come from? How can we help stop ghost nets occurring?
To answer some of these questions we recently (2012-1013) were able to workshop with some of the fishers that legally operate in the Arafura Sea.
Finding Local Solutions
At GhostNets Australia our major objectives is to protect our marine life and coastal environment by stopping the nets coming to our shores. What can we do to put an end to our ghost nets problem?
We have been engaged in locally cleaning up the mess, stopping the nets from getting washed back into the sea continuing their destructive journey.
We have ensured that local communities are equipped and trained to manage the ongoing problem so that it does not get out of hand.
But we have not stopped them at their source. For this we need to understand where the nets are coming from, the people that use them, the reasons they lose, abandon or deliberately discard nets, and the factors driving that behaviour. This section documents that journey.