Maritime Border Forces have uncovered tonnes of abandoned fishing nets, fish aggregating devices tethered to the ocean floor and what is believed to be illegally-set foreign gillnets in Northern Territory waters.

The operation to remove environmental hazards from the waters off the coast of the Northern Territory in July and August tracked down two large and abandoned fishing nets, also known as ghost nets, weighing three tonnes each.

Peter Venslovas, Australian Fisheries Management Authority’s manager of Fisheries Operations, said the nets were most likely abandoned by foreign fishers and have the potential to wreck havoc on marine life.

“As they drift into Australian waters [ghost nets] can be incredibly damaging entangling and slowly killing species such as turtles, dugongs, seabirds, dolphins and other fish species,” he said.

Border Forces discovered the first ghost net just 20 nautical miles northwest of Melville Island weighing an equivalent of about two cars, and containing a “small amount of dead marine life”.

On August 6, the Australian Border Force retrieved another ghost net 170 nautical miles northwest of Darwin, near Evans Shoal.

According to authorities, the net spanned two kilometres and contained both live and dead marine life including two sea turtles, which “were thankfully both alive and able to be cut free and returned to the water”.

An estimated 640,000 tonnes of fishing gear is lost, abandoned, or discarded in Australian waters each year, according to the NT’s alliance of conservation groups Keep Top End Coasts Healthy.

According to their data, between 2000 and 2014, 2,700 ghost nets were observed at sea and at various beaches across the Top End.

In that time, 370 washed up nets were found on land with entangled turtles and hawksbills.

On August 10, near Deliverance Island in the Torres Strait, an illegally set 200m long foreign gillnet was retrieved.

And FADs, typically buoys or floats which can have detrimental effects if they reach the land, were found inside Australia’s Exclusive Economic Zone, 110 nautical miles northwest of Bathurst Island after it had drifted in from foreign waters, Mr Venslovas said.

Maritime Border Command, Admiral Lee Goddard, said the operation illustrated the Australian Government’s commitment to responding to the range of threats in Australia’s maritime zones.

“Maritime Border Command and our partner agencies do an exceptional job protecting the Australian maritime border,” he said.

“As part of this we have an important role to play in safeguarding our marine wildlife and natural resources.”

Budget 2020-21: Protecting and preserving Australia’s environment

Federal Treasurer Josh Frydenberg handed down what has been described as Australia’s most significant budget since World War Two on Tuesday that had money earmarked to employ more Indigenous rangers to remove abandoned ghost nets.

Minister for the Environment Sussan Ley said the 2020-21 Budget will deliver key outcomes in protecting our oceans, preserving national parks and heritage areas, transforming the nation’s waste industry as well as continuing critical wildlife and habitat restoration.

“The Morrison Government is investing $67.4 million to protect our oceans and marine ecosystems,” she said.

“This includes $14.8 million to tackle the marine impacts of ghost nets and plastic litter and $28.3 million for compliance, enforcement and monitoring activities across Australia’s Marine Parks.”