Nylon, Polypropylene, Polyethylene, Polyester are the main polymers that make up modern fishing nets

Fishing nets are built in Nylon, Polypropylene, Polyethylene, Polyester and other materials that make the structures economical and tough, but which pose a serious environmental problem if abandoned in the sea.

This phenomenon very often depends on accidental situations in which fishing vessels lose their nets or parts of them, for various reasons, one of which is perturbations or difficult sea conditions.

The problem of pollution of fishing equipment lost at sea was already reported in 2009 by an FAO report when there was still no talk of plastic pollution in the seas.

According to the 2020 report of ECA Europe the abandonment and dispersion of plastic in the environment damage terrestrial and marine ecosystems. Each year, between 4.8 and 12.7 million tons of plastic waste is released into the ocean. The proportions of terrestrial and marine plastic waste vary from region to region.

According to a recent study, fishing nets also make up 46% of the Great Pacific garbage patch. In Europe, about 85% of marine litter found on beaches is plastic. About 43% of this marine litter is made up of single-use plastics and 27% of fishing gear.

In another report written by Greenpeace in November 2019 it was estimated that 640,000 tons of abandoned or lost fishing gear entered the ocean each year, equivalent in weight to over 50,000 double-decker buses.

In total, they make up about 10% of the plastic waste in our oceans, trapping and killing marine life.

The report was written while Greenpeace's ship, Arctic Sunrise, was examining Monte Vema, a biodiverse undersea mountain in the Atlantic, 1,000 kilometers off the coast of South Africa, where you can still find the remains of the once active fishing industry.

Speaking of the expedition to Mount Vema, Thilo Maack of Greenpeace's Protect the Oceans campaign said: "Long after their abandonment, fishing gear continues to kill, maim marine life and pollute also remote ecosystems such as the submarine mountain of Monte Vema.

We saw a fantastic underwater world full of life and color here. It is absolutely sad to see destructive fishing gear in such a remote place as this.

"Even the Tristan Lobster, an iconic species of Monte Vema, which has been on the verge of extinction twice, is now showing signs of population recovery, thanks to the current ban on bottom fishing . This shows how the oceans have an extraordinary ability to regenerate.

The "Ghost Gear" report shows that 6% of all nets used, 9% of all traps and 29% of all longlines (lines of several kilometers) remain polluting the sea .

Not only does old fishing litter continue to kill marine life, it also severely damages underwater habitats. Seamounts are particularly hard hit as they are often heavily exploited due to the variety of wildlife that live around them.

Greenpeace calls for stronger action to be taken against deadly phantom equipment, including agreeing to a strong UN Global Ocean Treaty that could protect at least 30% of the world's oceans by 2030, making it off-limits for harmful human activities, including industrial fishing.

While according to a report by FAO , already in 2009 the danger of abandoning nets at sea was denounced, however highlighting that most of the fishing equipment is not deliberately abandoned but is lost during storms, carried away by strong currents, or is the result of so-called 'tackle conflicts', for example, when fishing with nets in areas where traps have already been placed on the bottom where new nets can run aground.

The main damages caused by abandoned or lost networks are:

• the continuous capture of fish - known as "ghost fishing" - and other animals such as turtles, seabirds and marine mammals, which become trapped and die;

• the alteration of the ecosystems of the seabed;

• the creation of risks for navigation in terms of possible accidents at sea and damage to boats.

Tram nets, pots and fish traps contribute to "ghost fishing", while large fishing nets tend to trap other marine organisms and bottom trawls damage underwater ecosystems.

Ghost fishing

In the past, poorly managed fishing nets drifted by the current were singled out as the main culprits, but banning them in many areas in 1992 reduced their contribution to ghost fishing.

Today it is the trammel nets placed on the seabed that are most often recognized as the main problem. The lower end of these nets is anchored to the seabed, while at the top there are floats, so as to form a vertical underwater wall of nets that can extend from 600 to 10 000 meters in length.

If a trammel net is abandoned or lost, it can continue fishing on its own for months - sometimes years - indiscriminately killing fish and other animals.

Fish traps and pots are another major cause of ghost fishing. In the Chesapeake Bay in the United States, it is estimated that around 150,000 crab traps are lost each year, out of a total of 500,000.

On the Caribbean island of Guadalupe alone, around 20,000 of all traps set each year are lost in each hurricane season, a loss rate of 50%. Like trammel nets, these traps can continue to fish on their own for extended periods of time.

Photo: FAO