Ghost Net : the silent killer

Have you ever walked for a day without noticing a single piece of waste? Have you ever been in remote corners, closer to nature and far from humans, while having this dark vision of a bottle or a plastic bag spoiling the landscape? Unfortunately, all of this represents visible pollution, sadly a minority regarding the amount of waste in the oceans.

Have you ever walked for a day without noticing a single piece of waste? Have you ever been in remote corners, closer to nature and far from humans, while having this dark vision of a bottle or a plastic bag spoiling the landscape? Unfortunately, all of this represents visible pollution, sadly a minority regarding the amount of waste in the oceans. 

Ocean plastic has gathered lots of attention in recent years (as it should), but fishing gear makes up a huge chunk of that problematic plastic. Unlike plastic bottles, drinking straws, and grocery bags, this gear was designed for one purpose: catching and killing sea life. And it continues to do so long after the anglers who deployed it return to shore. The plastics that make up most of the nets in the oceans today take around 600 years to break apart

A report from the international nonprofit World Animal Protection (WAP) estimates that at least 700,000 tons of new ghost gear lines, pots and traps used in commercial fishing are dumped and discarded in the sea every year ( the same weight as 55,000 double-decker buses).

No alt text provided for this image

Once it’s there, it can harm all kinds of sea life, including turtles, penguins, sea lions, dolphins, whales, and diving shorebirds. The report found that 45% of all the marine mammals listed on the International Union for Conservation of Nature’s Red List of Threatened Species have been killed or harmed by abandoned fishing gear.

For example, almost 5000 derelict nets removed from Puget Sound through retrieval programs were entangling over 3.5 million marine animals annually, including 1300 marine mammals, 25,000 birds, and 100,000 fish.

No alt text provided for this image

A recent study of the “great Pacific garbage patch”, an area of plastic accumulation as large as Texas in the north Pacific, estimated that it contained 42,000 tonnes of mega plastics, of which 86% was fishing nets. Ghost gear is estimated to make up 10% of ocean plastic pollution but forms the majority of large plastic littering the waters. One study found that as much as 70% (by weight) of macroplastics (in excess of 20cm) found floating on the surface of the ocean was fishing related. 

It is important to know the effects on the ocean of the plastics we consume every day, but we must not underestimate the impact of ghost nets on marine life. These represent a significant part of marine waste and their impact is often overlooked by the general public compared to plastic bags, for example. The seafood companies take advantage of this ignorance by not applying strict recovery or investment programs in new technologies because there is not yet really any transparency or recognized label. Fish consumers could then buy from partner companies, which would put pressure on and increase the adoption of responsible behavior. Cooperation between the seafood industry, governments, and both intergovernmental and nongovernmental organisations is vital to ensure the safety of the billions of animals currently threatened by ghost fishing gear.

The deadly effects of ghost nets can be felt far from their point of origin. Ghost nets drift with ocean currents for years, or even decades. As they travel huge distances, they continue to catch and kill marine animals in a process called “ghost fishing”. Entanglement in ghost nets can lead to exhaustion, suffocation, starvation, amputations of limbs, and, eventually, the death of a marine animal. Entangled fish often act as bait, attracting larger predators such as turtles, sharks, and dolphins, which may themselves become entangled in the same net, therefore creating a vicious circle and negatively impacting the marine ecosystem. Lost fishing gear, or so-called ‘ghost gear’ is among the greatest killers in our oceans, and not only because of their numbers.

No alt text provided for this image

A drifting ghost net might eventually become so heavy due to its catch that it sinks to the bottom of the ocean. On the seabed, smaller ocean dwellers start feeding on the entangled marine animals, which, along with natural decomposition, reduces the weight of the net to the extent that it floats back up to the surface. Once the ghost net is again drifting with the ocean currents, it starts its cycle of ghost fishing, sinking and floating back up all over again. Due to the durability of modern fishing nets, this circle of devastation can continue for decades.

No alt text provided for this image

There are shocking statistics concerning ghost nets and their implications on marine life. Up to 30% of all fish are caught in ghost nets. Roughly 10%, or 640,000 tons of all marine debris are caught in ghost nets concentrating a huge share of plastic waste.

Among the effects on marine life, ghost nets also impact humans! This is a danger for humans swimming, surfing, diving and it can become a menace and be financially painful for local fishermen’s boats, tourist boats and leisure vessels. Ghost gear catches and kills fish stocks that would otherwise form part of the catch, and in some cases would be worth millions of dollars. Ghost gear has caused an estimated 5-30% decline in some fish stocks. In addition to these problems, gear replacement and repair costs also negatively affect fisheries in a variety of ways, including loss of fishing time or the financial impact of replacing lost gear.

The giants are also affected!

Whales ingest the nets and can die a slow painful death, from hunger and more. When North Atlantic right whales migrate along North America’s eastern seaboard, they run a gantlet of fishing lines in their path. Today 83% of the population shows signs of entanglement, a leading cause of death for this endangered species. Fishing for crab and lobster involves placing traps (also called pots) on the ocean floor and marking the spot with a surface buoy that’s connected to the traps with a sturdy line. But the lines routinely harm whales; they cut into flesh and impede the whales’ diving, surfacing for air, and feeding. To CT Harry of the International Fund for Animal Welfare, a remedy seems clear: “Fishing without vertical lines is what’s going to save this species.”

No alt text provided for this image
No alt text provided for this image
No alt text provided for this image

Why do Ghost Nets end up in the ocean ?

Illegal fishing

  • If an illegal fishing vessel is in danger of being caught, nets may be cut off or thrown overboard.
  • Companies involved do everything they can to avoid detection or capture, including abandoning gear
  •  Unlikely to be using marked gear

Economic causes

  • Proper disposal of discarded fishing nets can be very costly and some fisheries are not able to afford it. Dumping nets into the sea may be their preferred alternative.
  • High cost of retrieval
  • When a particularly good catch is made but the boat is full, it can happen that nets are thrown overboard to make room for the catch. 

Environmental influences

  • Trawl nets towed behind a boat may get caught on corals, wrecks or other obstacles and tear off.
  • Trammel nets that are firmly anchored to the bottom of the sea can be torn out of their mounts and drifted away by the current in a strong storm.
  • In addition, nets may go overboard in the event of an accident at sea.

In Belgium you get paid to turn in your nets, for instance, but in the Netherlands you have to pay because it’s considered industrial waste. That’s why some fishermen dump them in the sea. Knowing that every minute, one garbage truck of plastic is dumped into our oceans, it seems relevant to develop alternative solutions to nip these things in the bud.

The devastation that fishing techniques cause

Many fishing techniques and practices are destructive to the marine environment. They may for example cause over-fishing, massive by-catch, damage to the sea bottom and coral reefs, and ghost fishing. Of course, modern science has made many achievements, for example, you can buy Viagra 100 to treat impotence, but it is difficult to predict the consequences of the death of marine species. For example, derelict fish traps near Oman are estimated to cause marine mortality between 57 kg per trap in a three month period alone. One study estimates that over 15,000 traps are lost every year in this area.

Trawling and the use of gillnets, purse seine and FADs (Fish Aggregating Devices) are some of the problematic fishing techniques that create ghost nets. On the other hand, pole and line, the primary fishing technique in the Maldives, is a low impact and sustainable fishing technique but is not viable to meet global needs. These techniques create problems worldwide: in just one deep water fishery in the north east Atlantic, some 25,000 nets have been recorded lost or discarded annually. At current fishing levels, over the next 60 years in the Florida Keys alone, a staggering 11 million traps could become lost. 

Here are some examples of the most used fishing techniques by the industry:

Trawling

No alt text provided for this image

Trawling involves dragging a large fishing net with heavy weights behind a boat, either mid-water or across the bottom. The net indiscriminately catches or crushes everything in its path. Consequently, by-catch is extremely high and nets are often lost due to snagging on the bottom. Trawling is a common fishing technique in India and Sri Lanka.

Gillnets

No alt text provided for this image

The dominant fishing gear in the Indian Ocean is gillnet. Gillnets contribute as much as 30-40% of the total catch in artisanal and semi-industrial fisheries. It’s a set of panels of uniform mesh size, which form a large net-wall hanging vertically in the water. Suspended in the top- or mid-depths of the water (a drift gillnet), or anchored to the seafloor (bottom gillnet), gillnets trap fish by their gills. They are very effective and particularly destructive.

Purse-Seine

No alt text provided for this image

Purse seine is a long wall of netting deployed around a school of fish and pulled tight, thus enveloping the school of fish (and any other animals) in a purse-like structure. Purse seines target pelagic fish of all sizes, including tuna, and are therefore frequently used in the western Indian Ocean, often in combination with FADs.

No alt text provided for this image

Dredging

Dredging is similar to bottom trawling, but instead of a net, a metal rake of sorts is dragged across the bottom to collect shellfish and bivalves buried in the substrate, e.g. scallops, clams, or mussels.

No alt text provided for this image

Traps and Pots

By-catch is not a problem, but sometimes gear gets swept away or fishers forget where they set their traps. This is more connected to the whale’s entanglement problem seen in the first chapter of the article.

 

Solutions and Initiatives

Several solutions exist to recover and treat the ghost fishing gear already present in our oceans but also to reduce their volume before any pollution. This campaign is supported through the creation of the Global Ghost Gear Initiative (GGGI)  a multi-stakeholder alliance developing best practice solutions while working with stakeholders from the seafood industry.

Together with World Animal Protection they achieved a guideline that tackles ghost fishing gear through the 4 Rs :

  • Reducing the upstream quantity of fishing gear  
  • Removing ghost fishing gear from the  oceans  
  • Recycling ghost fishing gear with the creation of innovative startups and the development of the circular economy  
  • Rescuing wildlife by training rescuers to scout ghostnets and free animals entangled in ghost fishing gear.

To bring a proper answer to this guideline, several solutions are tested for a more sustainable fishing industry, drastically reducing the loss of fishing gear or their impact on the marine ecosystem:

One of the solutions to make it easier to identify ghost nets is clearly marking all gear with the port letters and numbers (PLN) of the vessel so it can be linked back to the owner. In all EU waters, fishing gear must be marked and when a fishing gear is lost, the fishermen have to  warn the fisheries authorities within 24 hours of the following. Unfortunately, illegal fishers and ones outside from Europe don’t pledge to this rule, leaving behind them untraceable nets.  

The manufacture of biodegradable gear is a promising solution but still too young to be implemented on a large scale. First you have to make sure that these biodegradable nets are as effective as the regular nets on the market (What is the point to make biodegradable fishing nets if the fishermen do not want to use them?). Research into new types of polymeric materials yields nets that begin to biodegrade after 24 months and are resistant enough to be efficiently used in fishing activities. With extra-researches in the following years, we could see a large implementation of this type of gear maybe with the creation of global regulations mandating biodegradable nets.

In addition to long-term actions, it’s also important to treat the symptoms of this disease by implementing collecting solutions for fishing gear. With the Buy-Back Programs for Found Gear, fishers are encouraged to collect waste fishing gear and to bring ashore the litter collected, as part of fishing activities. The boats are provided with hard wearing bags to facilitate the transport of the ghost nets and their delivery to the quayside. An economic incentive is also given to fishers: when they bring back waste fishing gear collected during fishing operations to the designated place, it is purchased at the cost of approximately US$10 per 100 litre bag. This project has been implemented successfully in the Republic of Korea since 2003 and could be spread worldwide. The fund would come from central and local governments and would also educate actors to carefully remove nets entangled in ecosystems to avoid extended destruction.

Startups involved:

Motivated by the issue and the possibility of having a positive impact on the oceans, many companies dedicate their ideas and their energy to the service of marine life : 

Plastixx (https://plastixglobal.com/)

This Danish company allows the recycling of ghost nets, ropes, trawls and thus removes them from our oceans while participating in a circular economy model. Indeed, the plastic fibers of the fishing nets are recovered and transformed into new Green Plastic raw materials, also called pellets. Their technology solves a significant waste stream problem, contributes to  reducing landfilling, marine pollution, CO2 emissions and loss of valuable resources. In partnership with other companies, they developed a wide range of useful products such as cellphone cases, furnitures and even kayaks.

SafetyNet Technologies (https://sntech.co.uk/)

One of the biggest issues from the commercial  fishing industry concerns by-catches as  1 out of every 5 fish caught is not marketable, legally too small to be sold or endangered. This problem leads to 16m tons of fish wasted every year. By-catches also waste around  20% of space in each vessel resulting in 500 000$ loss per vessel per year. With a forecast of increasing demand for fish by more than 70% by 2050, the oceans are being plundered without meeting global demand for fish.

To solve this problem, SafetyNet developed a solution called “Pisces”, a kit of underwater lights attached to the existing fishing gear that uses the potential of light to manipulate fish behaviour. This technology repels non-targeted species and can lower bycatch by 90%.

Ashored (https://ashored.ca/)

Ashored Inc., an ocean technology company based in Halifax, Nova Scotia, Canada, is focused on improving the sustainability and efficiency of the commercial marine fishery, and minimizing its impact on oceans through the development of innovative purpose-built technologies. Currently, Ashored is addressing issues of marine animal entanglements and derelict fishing gear with its ropeless fishing system (MOBI) and gear tracking system (ATLAS). 

Ashored retrofits existing lobster/crab traps with underwater buoys that can be called to the surface using an active-retrieval release, ensuring safe passage for marine life and surface vessels, while minimizing the risk of gear damage/loss for commercial harvesters.

NGO and Projects:

GhostNetWork  (https://www.ghostnetwork.org/)

This NGO collects GhostNets along the Portuguese coastlines and creates a Circular model by turning the nets into products with the collaboration of startups and other initiatives like art. They turn the nets into sunglasses, diving fins, dog and cat leads and bracelets. They also want to bring together a network of GhostNet Initiatives and clean up the oceans.

Oliver Ridley Project (https://oliveridleyproject.org/)

This NGO militates for the protection of the olive ridley turtle and the removal of ghost fishing nets. They also create jobs in Pakistan by working with locals collecting nets. The ultimate goal of our research is to provide recommendations on how to manage and mitigate the ghost gear issue. We also hope that our research results will prompt changes in fishing net and gear designs, as well as influence fishing legislation.

Remora project (https://alejandroplasencia.com/remora)

A smartphone app would let fishing boat captains keep track of their nets. The main target is the commercial tuna operators who use the “purse-seining” method of fishing, which deploys gigantic nets — some measuring more than a mile wide and 700 feet deep — around entire schools of fish. Furthermore, a biodegradable additive is added to the nets, which would cause the polymer to begin to break down after four years. The net is also studded with ultrathin RFID transmitters to pinpoint its location so it can be quickly repaired rather than abandoned.

If you know any innovations or organisations that could have been in this article, please let us know!

Co-written by Christopher Storey & Arthur Félétou

Special mentions and thanks for the references:

https://www.nrdc.org/onearth/single-discarded-fishing-net-can-keep-killing-centuries

https://oliveridleyproject.org/what-are-ghost-nets

http://bandeathnets.com/

https://www.nationalgeographic.com/animals/2020/05/endangered-north-atlantic-right-whales-thin/

https://www.worldanimalprotection.org/sites/default/files/media/int_files/ghosts_beneath_the_waves.pdf

https://planetlovelife.com/pages/the-problems

Download the Horizon Scan