End-of-life fishing and aquaculture gear: An assessment of the potential recycling capacity in Scotland

2. Methodology

To understand the reprocessing capacity for EOL fishing and aquaculture gear in Scotland, a mixed-methods approach was used. Desk-based research included mining data collected for Resource Futures’ 2021 study, reviewing recent secondary data (since 2021), and interrogating plastic reprocessor databases. Stakeholder engagement was also conducted with a variety of stakeholders relevant to the production, use, disposal, and reprocessing of fishing and aquaculture gear.

2.1. Desk-based research

2.1.1. Literature review

A brief literature review was conducted of recent studies on fishing and aquaculture gear quantities and material composition in Scotland. The aim of the literature review was to assess whether new research had been conducted since Resource Futures' previous estimates, which were made in 2021.^[13],[14] Academic and grey literature was identified by the project team’s expert technical advisor, and through searches on academic search engines such as Google Scholar and Scopus.

Due to a lack of new evidence for Scotland, the 2021 research by Resource Futures was used as a baseline to understand quantities of materials in EOL fishing and aquaculture gear. As outlined in section 3.1, the main plastic polymers were PP and PE, including high density polyethylene (HDPE).

2.1.2. End-of-life infrastructure identification

Desk-based research was conducted to understand what happens to EOL fishing and aquaculture gear in Scotland. This looked at how much is sent to landfill, incinerated or reprocessed; where (geographically) the material is sent; and current and future reprocessing capacity. Facilities were identified that handle EOL fishing and aquaculture gear or handle the in-scope polymer types.

Reprocessing facilities were defined as facilities that melt down waste plastics to create new plastic outputs, such as pellets, as a raw material for manufacturing new products. Reprocessing facilities may or may not conduct intermediate processing (also referred to as ‘pre-processing’) activities such as cleaning, sorting, chopping and shredding.

Sites and waste management routes were identified using online searches, waste data from Scotland and England, and public reprocessor databases, such as RECOUP’s Reprocessor Database and ENF Plastic’s British plastic recycling plants directory. The number of reprocessors of PE, HDPE and PP (respectively) in the UK are outlined in Table 1^[15]. Overall, 11 reprocessing sites were identified in Scotland, including four sites that might be accepting EOL fishing and aquaculture gear.

SEPA data from 2022 to 2024 was also used to identify waste tonnages of EOL fishing and aquaculture gear, and what happens to it (e.g. handled on-site, sent off-site, or landfilled). To identify appropriate records, all 2022-2024 data with EWC 02 01 04 were extracted and data cleansed by SEPA by reviewing the operator’s written waste descriptions. For all other EWC codes, an in-depth search was carried out by SEPA, using various key terms provided by Resource Futures (Appendix B). A range in granularity of search terms was provided to cover different levels of detail. These terms were used to search the written waste descriptions provided by operators in Table B of the site returns form. Duplicate search results were removed. The full methodology undertaken by SEPA, including the data limitations, is included in Appendix B.

Table 2 summarises the total number of records from each search and the number of relevant records after data cleaning. It also shows, of the relevant records, how many records had waste ‘treated on-site’ and consequently the number of sites that might accept EOL fishing or aquaculture gear. During stakeholder engagement, three of the relevant records were removed, as one site confirmed they had never accepted EOL fishing and aquaculture gear.

2.2. Stakeholder engagement

The interviews aimed to build a more detailed understanding of current and future reprocessing capacity, barriers and challenges, and opportunities to increase EOL fishing and aquaculture gear reprocessing in Scotland. Both quantitative and qualitative data were sought. In total, 42 interviews were carried out.

2.2.1. Stakeholder identification and grouping

Two overarching groups of stakeholders were identified and divided into further stakeholder categories, as follows below.

Group 1

Rationale for interviewing:

• Plastics reprocessors, who were critical to answering the key research questions and providing data on capacity.

Stakeholder categories:

• Plastics reprocessors in Scotland
• Plastic reprocessors outside of Scotland, who may receive gear from Scotland
• Specialist reprocessors of fishing and aquaculture gear in Scotland, the rest of the UK and Europe

Group 2

Rationale for interviewing:

• Other organisations relevant to fishing and aquaculture gear reprocessing value chains, who could contribute to a wider systemic understanding of the challenges and opportunities.

Stakeholder categories:

• Waste sector
• Commercial fishing sector
• Aquaculture sector
• Reuse and recycling output markets
• Local authorities
• Government organisations
• Non-governmental organisations (NGOs)
• Harbours, ports, and harbour authorities
• Other

2.2.2. Interviews with plastic reprocessors

Reprocessors were interviewed to gather quantitative insights related to reprocessing capacity and qualitative insights on challenges and opportunities for recycling fishing and aquaculture gear. This aimed to highlight what sites might accept fishing and aquaculture gear, how much they could potentially take, or reasons they would not take the material. The quantitative data on tonnage capacity would be used to estimate potential reprocessing capacity in Scotland based on current and future infrastructure.

Reprocessing sites in Scotland, and facilities outside of Scotland known to currently or previously reprocess any EOL fishing and aquaculture gear were ranked the highest priority for engagement. Reprocessing facilities outside of Scotland not known to accept EOL fishing and aquaculture gear were a second priority.

Engagement was conducted from May to August 2025. Each site outside of Scotland was contacted a maximum of three times, whilst sites based in Scotland were contacted more. The interview requests resulted in 27 responses. 17 respondents were interviewed or answered questions via email, and nine declined to take part (Table 3). A lack of interest in fishing and aquaculture gear was the most common reason for declining.

The interviews were semi-structured, covering quantitative and qualitative questions. The interview proforma can be found in Appendix C. A data collection template was prepared to capture data on reprocessor facilities. Data fields were defined to standardise data collection and facilitate analysis. The fields were designed to align with publicly available datasets provided by SEPA and the Environment Agency and extended to gather further qualitative information.

2.2.3. Interviews with other relevant organisations

Interviews with other relevant organisations aimed to understand the challenges and opportunities relating to the recycling of EOL fishing and aquaculture gear from the perspective of individuals and organisations along the wider value chain.

Participants in this group were identified and recruited through convenience sampling, supplemented by snowballing. Contacts were obtained through an existing network of industry experts in combination with desk-based research. Individuals were invited to participate based on their assumed knowledge of the topic and accessibility to the researchers. Individuals were contacted a maximum of three times, and interviews took place online.

Interview questions were developed for each stakeholder category focused on understanding the current disposal options for EOL fishing and aquaculture gear, barriers to recycling, and opportunities to increase domestic reprocessing capacity. The questions for each stakeholder category are included in Appendix D.

The interviews were semi-structured. The format allowed for flexibility in the order of the questions and follow-up questions. While the overarching questions remained for all stakeholders in each category, the researchers were able to explore some areas in more detail based on the expertise of the participant.

The number of interviews undertaken within each stakeholder category is presented in Table 4.

2.2.4. Data collection

Each interview was recorded and transcribed, with prior informed consent given by the interviewees. Researchers noted down relevant information during the interviews. After completing the interviews, researchers cleaned and reviewed their notes, using the recording and transcript to ensure accuracy and reliability of the information included in the analysis.

2.3. Data analysis

The data gathered through desk-based research and interviews was used to establish the current reprocessing capacity for plastic EOL fishing and aquaculture gear, and to explore the barriers and opportunities associated with expanding reprocessing in Scotland.

2.3.1. Reprocessing capacity

Best efforts were made to estimate current and potential reprocessing capacity for PE and PP in Scotland, using data on the 11 reprocessor sites identified (see section 2.1.2).

Interview findings shed light on:

• Current target polymer throughput (annual tonnage).
• Current spare capacity (based on waste management licences and existing equipment).
• Potential additional future capacity based on site expansion, new site development or new equipment.
• Which sites accepted EOL fishing and aquaculture gear, which had no plans to accept this, and which might under certain circumstances.

2.3.2. Planned and proposed infrastructure

Additional desk research was conducted to identify planned and proposed reprocessing infrastructure in Scotland, supplementing the interview findings.

Key search terms were used to investigate whether any plans for expanding Scotland’s reprocessing infrastructure were available in the public domain.

2.3.3. Barriers and opportunities analysis

The qualitative data gathered through interviews with all stakeholder categories was synthesised and analysed, using thematic analysis, to address the overarching research questions: what is the current capacity for reprocessing Scottish plastic fishing and aquaculture gear, and what would enable domestic reprocessing to scale up?

2.4. Developing case studies

Three organisations were chosen for the case studies, to highlight domestic and international success stories, and opportunities for future reprocessing. Case studies were developed by reviewing secondary data for each organisation as well as primary data gathered through interviews and, in one case, a site visit.

2.5. Data visualisations

2.5.1. Value chain visualisation

A flow diagram was created to illustrate the value chain and activities required for reprocessing EOL fishing and aquaculture gear. This was built iteratively throughout the stakeholder engagement. It maps the pathway from the generation of EOL fishing and aquaculture gear to reprocessing in the UK into high- and low-quality products. It also details alternative pathways, such as mismanagement, re-purposing, export, or landfill and incineration. The map was produced using Canva and can be found in section 3.2.4.

2.5.2. Spatial mapping of reprocessing infrastructure

ArcGIS software was used to map the current reprocessing infrastructure against areas in Scotland with the highest fishing and aquaculture activity. This exercise mapped the known facilities that currently take EOL fishing and aquaculture gear, those that do not, and those that could take it in future under certain conditions. The locations of these facilities were plotted to visualise the proximity to fishing ports, harbours and aquaculture sites. The following open-source layers were used:

• Aquaculture sites in Scotland: Sites were filtered to only include salt and brackish water locations. A heat map feature was then used in ArcGIS to show the highest concentration of aquaculture activity in Scotland.^[16]
• Plastic waste arising from Scottish fisheries: Using data from Resource Futures’ previous research, annual plastic waste (PP and PE) arising from Scottish mobile and static fisheries was mapped in ArcGIS against commercial fishing ports in Scotland.^[17]