Oceans make up more than 70% of the Earth’s surface and provide habitat for many organisms, including fish and other animals. There is no denying that human activity is negatively affecting ocean ecosystems. One problem is lost fishing gear, which poses a threat to marine life and affects water quality. Until now, the scale of this phenomenon has been difficult to estimate, but a new study reveals just how huge the problem is. Each year, enough nets are lost or discarded to cover Scotland, and if all types of lost lines were combined, they could circle the Earth as many as 18 times.
Australian study determines amount of fishing gear lost at sea each year
According to a study by CSIRO, Australia’s national science agency, and the University of Tasmania, nearly 2% of commercial fishing gear is lost or discarded each year, making it a major component of global marine plastic pollution.
For the most comprehensive study possible, the researchers analyzed catch data and interviewed 450 fishermen from seven countries around the world, including the US, Indonesia and Morocco. The surveys focused on the five main gear types (gillnets, purse seines, trawls, longlines, and pots and traps), how much they are used and lost annually, and gear and vessel characteristics that may affect losses.
Annual losses included:
- 78,000 km2 of purse seines and gillnets;
- 215 km2 of bottom trawls;
- 740,000 km of main ropes;
- 15.5 million km of branches;
- 13 billion longline hooks;
- 25 million traps and pots.
Richard Leck, head of the oceans at WWF Australia, said: “These numbers are breathtaking. It gives a sense of the frightening magnitude of the problem and the urgent need to solve it.”
In earlier estimates, the percentage of tools lost was higher, but those analyses were based on a series of surveys, not standardized estimates based on interviews.
“The data collected to create these estimates came directly from the fishermen themselves to gather information on gear losses directly from the source,” said Kelsey Richardson, lead author of the study.
Causes of loss of fishing gear and the effects of the phenomenon on marine ecosystems
One of the main reasons for the loss of fishing equipment is its poor technical condition and wear and tear. Many fishing nets and other gear are used for many years, leading to gradual wear and crumbling. Eventually the nets or hooks get torn and end up in the ocean. Another reason for lost fishing gear is bad weather conditions, which can lead to broken nets or anchors.
The consequences of losing fishing gear to marine ecosystems are very serious. Lost fishing nets, especially those made of nylon, can remain in the water for decades and become a trap for marine animals. This leads to a reduction in fish populations, which affects fisheries and the marine economy, but can also lead to changes in the populations of predators that eat fish, which in turn affects the food chain and the marine ecosystem as a whole.
“Spectrum nets – as we call them – are a particularly deadly form of pollution for all the marine life we care about. Once these nets are lost, they don’t stop fishing.” – Richard Leck
Lost fishing gear poses a serious threat to marine life and ocean ecosystems around the world. Research reveals that it contributes to the death and injury of many marine animals, as well as affecting water quality and fish stocks. The data will be used to help the CSIRO achieve its goal of reducing by 80% by 2030. The amount of plastic waste entering the environment.