Professional fishing - the main source of plastic waste

Fishermen also appreciate the positive properties of plastic, especially the ease of handling and the greater durability and reliability compared to natural materials. Around 4.6 million boats go fishing in the oceans every day. This also leads to material losses: The WWF estimates that 40 % - 50 %[1] of plastic waste comes from lost fishing gear alone - ropes, lines, buoys, baskets, buckets, fishing lines and nets. Over 1 million tons are added every year.

The phenomenon was discovered during investigations into the world's largest garbage patch in the North Pacific between Hawaii and California - the Great Pacific Garbage Patch (GPGP). The surprising result: the majority of the plastic waste, around 70%, was actually fishing equipment, 46% of which was ghost nets, weighing around 705,000 tons[2].

Current studies not only confirm the findings but also increase the figures: according to an analysis by the environmental initiative “The Ocean Cleanup”[3], known as the marine debris catcher, between 75 and 86 percent of plastic waste in the GPGP comes from deep-sea fishing.

How can this happen? Equipment goes overboard during fishing operations, storms or accidents. Set nets and trawls also break off and drift through the oceans abandoned as “ghost nets” or get caught on the bottom, on rocks, reefs or wrecks.

Recovering ghost nets is time-consuming, as they first need to be tracked down; sonar has recently been used for this purpose, and there are also plans to equip nets with GPS trackers. Lifting them is manual work, the nets are often stuck and need to be painstakingly freed. Their robust material mix requires intensive recycling. Countries, research institutions, environmental organizations and fishing companies are now aware of the importance of the issue and are already initiating countermeasures.

Rivers are effective transportation routes - also for waste

The second reason for plastic waste ending up in the oceans can also be precisely identified: Studies show that the global supply of waste from land to the oceans can be narrowed down to the 10 largest waterways from Asia and Africa. These alone flush around 12 million tons of plastic into the maritime waters every year. The Yangtze River leads the way, followed by the Indus, Huangho, Nile, Ganges, Niger and Mekong. A consequence of the rapid economic growth in these regions, the development of waste disposal has still not been able to keep pace with this dynamic.

In the meantime, active investments are being made here - for the expansion of orderly disposal and effective recycling of waste. For example, its incineration for energy generation in appropriately equipped power plants. This is a way of dealing with waste, which also improves marine pollution.

Another approach also promises to help: as the global transfer of waste to water is mainly concentrated in the aforementioned 10 rivers, this opens up the possibility of taking local measures to combat it. As “The Ocean Cleanup” is already doing here: the organization has developed a new interceptor system for use in rivers. The “Ocean Cleanup Interceptor”, a solar-powered, 24-metre-long boat with a screening device and container, is designed to filter up to 50 million tons of waste per day from flowing waters - before it reaches the oceans. A commitment that could set a precedent.

What's the matter:

A study by ocean experts led by Dr. Britta Denise Hardesty, head of research at the Australian scientific institution CSIRO Oceans and Atmosphere, has brought clear facts to light. For this purpose, 451 fishing companies in 7 countries were surveyed[4]:

Over 2% of all fishing gear is lost every year.

There are now 25 million fish traps (fishing cages) and 14 billion baited hooks in the oceans.

In addition:

2,963 square kilometers of gillnets - larger in area than the German Saarland (2,570 square kilometers),

75,049 square kilometers of ring wall nets - more than the largest German federal state, Bavaria (70,550 square kilometers),

218 square kilometers of trawl nets - the equivalent of around 30,000 soccer pitches,

739,538 kilometers of longlines and mainlines - enough to wrap around the world 17 times - and 11.5 million branch lines.

What is done:

Measures to prevent plastic waste from fishing gear:

The “International Convention for the Prevention of Pollution from Ships”, known as MARPOL, prohibits the discharge of pollutants into the sea.

The EU Fisheries Control Regulation prohibits the dumping of fishing gear at sea. Lost nets must be reported to the authorities.

With the “Marelitt Baltic” project, fishing communities, research institutes & environmental associations from Sweden, Estonia, Poland & Germany are investigating how plastic nets can be recovered & recycled. Organizations and projects such as “AegeanRebreath”, “GhostNets Australia”, “Ghost Diving” and “Healthy Seas” are committed to the recovery, disposal and recycling of ghost nets.

[1] Veröffentlichung WWF Themen & Projekte Geisternetze 17.08.2018
[2] Scientific Reports: Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic 2018, L. Lebreton
[3] Study „The Ocean Cleanup“ (Müllsammler System 001/B 2019), „Der Spiegel“ 05.09.2022
[4] Veröffentlichung Science Advances, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Publikation „GEO“ 14.10.2022

Image Source: ALPLA

Image Caption: Plastic also has a firm place in commercial fishing: it is superior to other materials in terms of weight, handling and durability.