Underwater world haunted by ghost networks

Ghost nets are old fishing nets or fragments of nets that are lying in the sea. They were most often lost by fishermen during storms due to being caught on objects or landforms lying on the sea floor.

Fishing gears are primarily made of materials that are not subject to natural decomposition. In addition, they are dyed to make them less visible in the water, and then equipped with various types of floats or weights. And all this is done to make them a more effective tool for fishermen. For the same reasons, if left in the sea, they become a deadly trap and generate uncontrolled bycatch of stumbling fish, crabs, lobsters, birds and even marine mammals, which, trapped in the ghost net, perish.

Spectrum nets endanger not only animals, but also humans (for example, they can pose a direct threat to divers). In addition, like other marine debris, they significantly affect tourism, destroying the natural beauty of valuable areas.

Over time, the nets degrade, turning into microplastics, thereby contaminating the water and entering the food chain.

What are spectrum networks?

According to HELCOM’s definition of derelict fishing gear at sea, or so-called “ghost nets,” are both commercial and recreational gear that has been abandoned, lost or otherwise introduced into the marine environment, as a result of which it negatively affects it.

Fishing gear lying in the seas and oceans and its impact on the marine environment is the subject of numerous projects and studies not only in the European Union, but also around the world. As a result, public awareness of the problem of marine debris, including abandoned nets, has increased in recent years.

Limfjordsrådet project

Limfjorden is a scenic waterway in the northern part of Denmark. It is the country’s largest fjord and an important natural and cultural resource. However, a large number of lost or abandoned fishing nets threaten the area’s biodiversity.

This has caused 18 municipalities surrounding the Limfjorden fjord to implement the joint Limfjordsrådet project, which is funded by the European Union – European Maritime and Fisheries Fund. Its goal is to solve the problem of ghost nets in the region.

The project is a large-scale cleanup of Denmark’s largest fjord. The first action took place in the spring of 2024, at which time some 41 t of ghost nets were collected, and expeditions covered nearly 75 percent of the fjord. The work is scheduled to be completed in spring 2026.

Local efforts supported by technology – key to Limfjordsrådet project implementation

Spectrum nets are usually found by larger vessels, but in sensitive areas, such as shallow reefs, seagrass beds or clam beds, they can be located visually from small boats or by drones. Therefore, local commercial and recreational fishermen, as well as divers, play a large role in identifying likely net sites.

In order to remove all ghost nets from Denmark’s largest fjord, any citizen who notices them can report them to the relevant services via an online tool developed as part of the Limfjordsrådet project. As the project team itself points out, the digital reporting platform has influenced faster and more efficient identification of pollution sites.

Already the results of the project’s implementation can be seen – this approach has helped estimate the scale of the problem and make sure that no net is ignored during the cleanup campaign.

Prevention as part of solution to spectrum network problem in Denmark

The key to long-term sustainability and prevention of net pollution in the waters is first and foremost to reduce the number of lost or abandoned nets. All fishermen in Denmark are required to report such losses to the Danish Fisheries Agency (Fiskeristyrelsen). This helps reinforce prevention, which is just as important as cleaning up the waters themselves.

According to the Limfjordsrådet project team, by streamlining reporting and accounting, the problem is solved at its source.

Spectrum networks in the Baltic

In recent years, there have been an increasing number of initiatives in the Baltic Sea to reduce the negative impact of spectrum networks. Poland is one of the European leaders in this topic. WWF estimates that several hundred tons of ghost nets are deposited in the Baltic Sea .

The first documented activities aimed at fishing out ghost nets from the Polish waters of the Baltic Sea were carried out as early as 2004. In recent years, Polish fishing organizations, in cooperation with the MARE Foundation, have carried out two editions of the Clean Baltic campaign (in 2017 and 2020), which consisted of fishing out marine debris, particularly lost fishing gear, from the Baltic Sea.

In 2017, search operations were conducted by units affiliated with five Polish fishing organizations. Nearly 147 tons of waste were fished out of the sea as part of the activities. In 2020-2021, nine Polish fishing organizations were involved in search operations. At that time, a total of more than 160 t of waste was landed. The predominant part was lost fishing gear, tires and various types of plastic.

What happens to the nets after they are fished out

Old fishing nets fished out of the seas and oceans are usually treated as waste. As a result, they are being incorporated into efforts to transition to a closed-loop economy, on the premise that products, raw materials and resources should remain in the economy for as long as possible, helping to reduce waste generation. Nevertheless, the issue of recycling lost fishing gear fished out of the water remains problematic.

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In the article, I used:

https://oceans-and-fisheries.ec.europa.eu/news/haunted-ghost-nets-2025-10-30_en?prefLang=pl
https://www.wwf.pl/morze-sieci-widmo
https://fundacjamare.pl/sieci-widmo/