The total size of fishing nets lost or dumped in the ocean each year is equal to the size of South Carolina, scientists have estimated.
Designed to be durable and long-lasting, lost or discarded fishing gear is a major contributor to ocean pollution and its harmful effects can be seen in the estimated 300,000 whales and dolphins that are killed each year due to entanglement of fishing gear, according to the World Wildlife Fund (WWF).
Lost fishing gear also produces an alarming amount of microplastics – tiny, ubiquitous plastic particles that are increasingly found everywhere on Earth, from the summit of Mount Everest to the fetuses of pregnant women. A study has found that the UK fishing fleet alone could release between 326 million and 17 billion microplastic fragments from fishing rope each year.
In a new study published in the journal Scientists progress on October 12, Australian researchers calculated that 75,000 square kilometers (28,957 square miles) of purse seines – a large wall of nets deployed around an entire area of fish – could be lost to the ocean every year.
This is in addition to just under 3,000 square kilometers (1,158 square miles) of gillnets and 218 square kilometers (84 square miles) of trawls.
Taken together, this area of nets is about the same size as the US states of Maine or South Carolina in terms of square miles.
The pollution does not stop there. The researchers also estimated that 459,555 miles of longline fishing line are lost in the ocean each year – enough to stretch from Earth to the Moon and almost all the way back – as well as 25 million traps and of traps.
The figures are based on interviews with 451 fishermen from seven countries about their annual gear use and losses. These reported loss rates were then multiplied globally based on global fishing effort data.
Interviews suggested that even a single fishing vessel loses around 58,000 square meters of purse in its nets each year on average.
Tamara Galloway, who holds a chair in ecotoxicology at the University of Exeter in the UK, said Pleasemynews the figures were “staggering” and “reflect the reality of the world’s dependence on seafood”.
She said lost or abandoned nets are particularly at risk of “ghost fishing”, in which marine life becomes entangled and dies. In addition to causing suffering in animals, this phenomenon also leads to significant losses of protein sources as well as loss of habitat.
“There have been some very successful interventions around biodegradable nets made from biomass waste, ‘fishing for litter’ plastic waste recovery projects, floating port bins, etc., but not all countries are not inclined to legislate for these,” Galloway said.
“Our recent research in the remote Galapagos Island, for example, has found microplastics at the base of the marine food web, and we have also quantified microplastics in high-value seafood destined for human consumption in Australia, showing that what we throw away can really come back to harm us.”
Coleen Suckling, assistant professor of sustainable aquaculture at the University of Rhode Island, said Pleasemynews“Fishing gear is often designed to withstand harsh ocean conditions and to hold a lot of weight, but that often means that some of those lost materials and gear will continue to exist for long periods of time.”
Suckling said ghost fishing due to lost or discarded gear can affect vulnerable species such as sea turtles, sharks, rays, seabirds and marine mammals.