A loggerhead turtle trapped in an abandoned net in the Mediterranean sea Nature Picture Library / Alamy Stock Photo

Hundreds of thousands of tonnes of lost, abandoned and discarded fishing gear litter the world’s oceans. In some areas, this gear accounts for 30 per cent of the catch, trapping turtles, seabirds and whales as well as commercially fished species.

Kelsey Richardson at CSIRO, Australia’s national science research agency, and her colleagues combined 68 studies from 32 countries and territories to assess the scale of the problem.

The team found that 6 per cent of nets, 9 per cent of traps and 29 per cent of lines are lost to the ocean each year from commercial fishing. While the line losses are highest in percentage terms, these were often just a section of line, whereas when a trawl net was lost this frequently meant the entire trawling gear.


The researchers found that the most common causes of loss were bad weather, gear getting caught on the sea floor and “gear conflict”, where pieces of equipment get tangled up with each other. Types of nets that drag along the sea bed are the most likely to be lost.

Previous studies have revealed that “ghost fishing” by abandoned gear can catch vast quantities of fish. This includes up to 5 per cent of the catch in the Baltic Sea and up to 30 per cent of Norway’s Greenland halibut. Studies tend to focus on the waters around Europe and the US and little is known about the African, Asian, South American and Oceania regions.

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Abandoned gear makes up much of the plastic waste in the world’s oceans, including 46 per cent of the plastic in the Great Pacific Garbage Patch.

“When plastic fishing gear pollutes our global ocean, it can persist for hundreds of years. We haven’t been using synthetics long enough to see plastic fishing gear disappear or entirely break down,” says Richardson.

When it does finally break down, plastic gear can enter the food chain as microplastic particles.

The next stage of the research involves interviewing fishers around the world about how much gear they lose and why, and coming up with possible preventive measures. This will feed into a more exact estimate of global loss and inform plans to mitigate the problem.

“The human activity with the biggest impact on the health of our oceans is fishing, and this study highlights an often-forgotten part of the problem,” says Helen McLachlan, fisheries programme manager at conservation organisation WWF-UK, emphasising the need for action. “We must do all we can to minimise the loss or abandonment of gear across our oceans, for the sake of our marine life around the world.”