Ghost nets haunting our oceans


A team of Eco-entrepreneurs find new uses for destructive nylon fishing nets and explore alternatives

Ghost nets are commercial fishing nets that have been lost, abandoned or discarded by fishermen at sea. These nets are often invisible in the dim light and sit on the ocean floor, entangled in rocks. The awareness of plastic in our oceans is prevalent at the moment with beach clean ups, social media campaigns and BBC documentaries encouraging us to reduce our consumer need for plastic bottles, food containers and straws. Ghost nets are not often part of this conservation, but perhaps they need to be. Ocean Cleanup estimate that ghost nets account for 50% of the plastic in our oceans, entangled wildlife and lurking menacingly on our ocean floors.

In this blog, I will share a project five STEM students created and worked on to raise awareness of the dangers of Ghost nets.

Eldridge Cleaver famously said ‘There is no more neutrality in the world. You either have to be part of the solution, or you’re going to be part of the problem.’ Being part of the solution is hard, it requires grit, passion and the ability to think differently. Interestingly, these are the key attributes most employers seek in their employees and most parents dream of for their kids. Groups of divers like the Ghost Fishing Foundation to great work locating and removing these ghost nets, but they are fighting against the symptoms of the problem. What if we could solve it at the source?

The STEM team are working hard to raise awareness of the dangers of fishing nets in the oceans. They are collecting discarded nets, liaising with local fisherman and beach clean ups and researching alternatives to traditional nets to explore the possibility of biodegradable netting. Here is an overview of how they are using STEM to tackle the problem.

Science – Modern nets are made from artificial polyamides like nylon and polyethylene which when exposed to sodium in our oceans can take over 200 years to biodegrade. When the fibres that bind the nets together do begin to decay they split into micro-fibres and micro-plastics which are consumed by fish, seabirds and marine mammals. Once consumed, the plastics sit in the stomachs of marine animals tricking them into thinking they are full. This causes many species to perish from starvation, depleting fish stocks and ravaging our marine ecosystems.

Engineering – A promising new study published in the journal Animal Conservation offers an alternative biodegradable net, blending 82% polybutylene succinate (PBS) and 18% polybutylene adipate-co-terephthalate (PBAT). These fibres biodegrade completely after 24 months in seawater and don’t create the same monofilament microplastics. During lab testing, the biodegradable nets had a lower breaking strain and performed inferiorly when compared to traditional nets. More research needs to be conducted and new alternatives tested.

Art and Technology – The STEM team have been salvaging ghost nets from the jurassic coast and will begin up cycling them into new products.

In the design stage, the team wanted to explore the reality of working with nylon. This proved to be a huge challenge. Unpicking fishing nets is a tough job! The tough durable and non-pliable nature of nets makes it a tough fabric to bend, weave and create with. We are grateful to Lynn from @the_upcycle_movement for her support and advice about how to work with the nets.

At the end of April, we collected crates of fishing nets donated by Lush Cosmetics. These nets were used as part of their ocean floor display at the Lush Summit in 2018. The team plans to repurpose these nets into new products to fund the next stage of their project.

Fishing nets are commonly made of synthetic polymeric fibres such as high densitypolyethylene (HDPE), polyethylene terephthalate (PET) or polyamide (PA), materials which are non-biodegradable and typically neutrally buoyant. For this reason, the discarded nets can drift long distances at variable depths within the oceans. These so-called ghost nets represent a problematic waste fraction in the marine environment since they can lead to entanglement of marine mammals, fishes, birds or active fishing gear. The Great Pacific Garbage Patch is one such example of when plastics gather in a specific place due to ocean currents.

In a pioneering study commissioned by Circular Ocean (2016) engineering properties and tensile strength of HDPE (High Density Polyethylene) were conducted using Young’s modulus to assess the breaking point of these fibres. The mechanical properties obtained by tensile testing are shown in Table 1 and 2, and stress- strain relationship is illustrated for unconditioned fibres in Figure 4. The tensile strength for new and waste fibres ranged between 403-445 MPa and 312-370 MPa, respectively. The peak strains for both new and waste fibres varied between 26-33 %. The new fibres obtained tensile strengths which were about 20 % higher than for the waste fibres, whereas the elongation strain for both new and waste fibres were very similar.

Data sourced from Ida Maria Gieysztor Bertelsen & Lisbeth M. OttosenEngineering properties of fibres from waste fishing nets
Materials, Systems and Structures in Civil Engineering 22-24 August 2016

Findings from the paper suggested that fishing nets fibres could be used within cement to bond and give tensile strength during construction. Another interesting use for a plastic that is littering our oceans.

Working with the nets

People have created all kinds of cool things from fishing nets, ranging from bracelets to hammocks. The STEM team planned to create some products they could sell to fund the campaign.

Production on the fishing nets starts in early June with bracelets, hammocks and doormats scheduled for creation. In addition, the team are looking to local artists who would be happy to work with them to create a sculpture out of a combination of the nets and plastics. The sculpture would help promote the campaign and raise awareness of fishing nets as a source of ocean plastics.

Companies doing it differently and reusing old nylon nets

BUREO take discarded fishing nets in Chile and make them into skateboards
This National Geographic documentary explores the use of fishing nets as carpets
Econyl is 100% regenerated nylon yarn, using fishing nets and fabric scraps. Zoggs and other sustainable companies are exploring the possibilities of this new product

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