1. Reducing the environmental impact of conventional fishing line.

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The GreenTide project directly addresses one of the biggest environmental, critical and economic problems related to the oceans: the pollution caused by non-biodegradable fishing line. In this project, we drew on a number of sources, such as scientific articles, studies on the biodegradability of materials and sustainability reports (Chemical extraction and modification of chitin and chitin from shrimp shells https://doi.org/10.1016/j.eurpolymj.2021.110709, Biomimetic generation of the strongest known biomaterial found in limpet teeth https://doi.org/10.1038/s41467-022-31139-0). We also consulted experts in biodegradable materials and environmental engineers from various faculties (Professor Luísa Santos from Maia High School, https://pt.linkedin.com/in/lu%C3%ADsa-santos-5ab90446, Doctor Andreia Peixoto from FCUP, https://sigarra.up.pt/fcup/pt/func_geral.formview?p_codigo=500924, Inês, PhD student Andreia Peixoto from FCUP). The use of non-biodegradable fishing line is a problem in the growing accumulation of fishing waste and represents a major environmental challenge, especially in the fishing sector.  Conventional yarns, composed mainly of non-biodegradable plastics and metals, contribute to global pollution and take centuries to degrade. GreenTide aims to develop an innovative and sustainable solution by creating biodegradable yarns using chitin, a component of shrimp shells, and the mineral tungsten, so that they can replace traditional yarns, reducing environmental impact and promoting sustainability in the fishing sector. The initial research is based on a literature review of biodegradable and compatible materials, exploring alternatives such as polymers, chitin, and minerals such as tungsten. Previous studies indicate that materials such as chitin (from shrimp shells) and tungsten have the potential for more sustainable applications, and that they are compatible for joining.

 

Keywords: Fishing threads, Biodegradability, Sustainability, Chitin, Compatible materials.

 

2. Introduction

 

Fishing line is an essential component of any angler's tackle. It is used to connect the hook and the bait and is essential to prevent the fish from breaking free from the line. Fishing line comes in several categories, such as monofilament line, fluorocarbon line and traced line. These are composed of highly resistant synthetic polymers such as nylon, polyester or polyethylene, which are widely used due to their durability, flexibility and low production costs. However, the growing use of these materials has led to environmental concerns, especially due to marine pollution resulting from improper disposal. The accumulation of fishing line in the ocean poses a threat to marine life, contributing to the degradation of aquatic ecosystems and the formation of long-lasting plastic waste. Nylon, for example, is a material that can stretch up to 30% before breaking, making it ideal for absorbing sudden shocks when a fish attacks. Fluorocarbon, on the other hand, is virtually invisible underwater, making it ideal for catching demanding fish. Braided lines are composed of several synthetic fibers that are woven together to create a super-strong line that is resistant to abrasion, chemicals and UV damage. The characteristics and physico-chemical properties of polyethylene (PE) are that it is a material: thermoplastic and easy to process, it is flexible, it is resistant to low temperatures, tensile stress and abrasion, it has low thermal conductivity, it is dielectric (the physical properties of polyethylene associated with the conduction of electricity are different for each type of PE polymer). Its density varies from 0.92 g/cm³ to 0.96 g/cm³. Depending on the density of the particles, PE plastics can be transparent, semi-transparent or white. Polyethylene - a combustible material, which melts quickly when exposed to high temperatures. Polyester is produced using non-renewable resources, from chemical substances extracted from crude oil or gas, and it also uses a lot of water to cool the product. Polyester can be made from recycled plastic bottles and if it is not mixed, it can be melted down and recycled later. Being made from non-renewable resources, synthetic fibers are not biodegradable and take around 400 years to fully decompose. As it is a complex process, production raises some environmental concerns. Some producers use crude oil to isolate the polymers, which can lead to the depletion of fossil fuels and environmental pollution from run-off. The chemical production of edipic acid also often creates nitrous oxide, which is a greenhouse gas. This gas has the potential to erode the ozone layer and promote air pollution.

At the moment, there are still no biodegradable fishing threads that simultaneously maintain the strength required for fishing and  controlled degradation in the marine environment. The GreenTide project aims to develop biodegradable fishing line, reducing the pollution caused by the disposal of synthetic line in the oceans. The proposal consists of using biodegradable polymers that guarantee adequate mechanical strength during use, but which, when lost or discarded, decompose naturally without harming marine ecosystems. This innovation faces challenges such as the durability of the yarn in a saline environment, tensile strength to withstand the strain of fishing and compatibility with production methods already used in the fishing industry.

To this end, formulations combining minerals such as tungsten and polymers such as chitin have been explored to provide the necessary strength for biodegradable fishing yarns. The GreenTide yarn production process is based on the extrusion of modified polymers, as described by recent studies on biodegradable materials, but with specific adjustments to meet the requirements of commercial fishing. The approach adopted seeks to balance strength and biodegradability, ensuring that the yarns do not break prematurely during use, but decompose efficiently after disposal in the aquatic environment. The conception of this project originated from the influence of Leonor's (a member of the group) father and his passion for fishing, which motivated the group to come up with the idea of developing a biodegradable fishing line. His experience and knowledge on the subject were fundamental to understanding the essential characteristics of fishing yarn and the processes involved in its production. Our final product will be fundamental in reducing pollution, reducing the mortality of marine animals and also financially, since conventional yarn gets tangled up in the tails of boats, causing the engine to break down.

In this way, we are not only looking after the safety of marine life, but we are also reducing the high costs of repairing engine damage, bringing economic benefits to fishermen. The implementation of a biodegradable fishing line thus represents an innovative solution that balances environmental preservation with financial and operational benefits. From the outset, our goal has always been to do something impactful that could really make a difference.