Extreme Weather a Major Cause of Plastic 'Ghost Gear'

A new white paper from the Aquaculture Stewardship Council (ASC) published on 28 November has determined that extreme weather is currently one of the major causes of plastic ‘ghost gear’ from fish farms entering oceans and rivers, and warns that the increasing "frequency and severity" of tropical storms due to climate change could exacerbate the problem.

The white paper, Marine Litter and Aquaculture Gear, has for the first time classified the different causes of plastic waste from aquaculture and assessed the risks to different farming systems.

The paper has been commissioned and published by ASC to provide scientific rigour and evidence to the planned update to ASC standards to include requirements on this issue, but also includes recommendations for the wider industry.

The paper gathers evidence from various sources including 60 ASC certified farms, and finds that the three main causes of plastic pollution from aquaculture can be classified as: mismanagement, deliberate discharge, and extreme weather. It assesses the relative risks of each of these causes for different aquaculture production methods, and also makes recommendations for the aquaculture industry, which can be summarised using five R’s: Reduce, Re-use, Recycle, Recover, Refuse.

“The issue of ghost gear from fisheries is well known, but there has been much less analysis of the impact of fish farms,” said Marcelo Hidalgo, Standards Coordinator for ASC. “ASC plans to be the first aquaculture certification scheme to include specific plastics requirements, and as a science-based organisation it was important for us to make sure they are evidence-based.”

The white paper finds that while lost plastics from aquaculture and capture fisheries are often considered together, this is a not a helpful approach as the causes are often quite different.

Comparing the pathways of plastic waste from different aquaculture systems shows that in most cases the highest risk comes from the gradual and long term impact of poor waste management, or less frequent but higher-impact extreme weather. It warns that because of the high proportion of aquaculture sighted near or on coasts and increasingly unpredictable weather caused by climate change, it is likely that extreme weather will continue to be a major cause of lost plastics into the future.

“We’re really proud that we were able to use information from ASC certified farms to help produce this important paper, and we hope it can help improve standards across the entire industry,” said Marcelo. “We will be sharing these findings and working together with the United Nations Food and Agricultural Organisation (FAO) and International Maritime Organisation (IMO), as well as the Global Ghost Gear Initiative (GGGI) to collaborate on finding solutions to this problem that affects us all.”

The white paper recommends what it calls the five R’s for aquaculture producers looking to reduce plastic waste:
• Reduce: this includes reducing plastic abrasion or equipment failure by using the most appropriate materials, and reducing the risks from unforeseen events by developing stringent risk assessments and contingency plans
• Re-use: the paper suggests that cheap single-use equipment can be both environmentally and economically more expensive than higher-specification alternatives – for example using reusable gloves rather than single-use latex gloves
• Recycle: for example, engaging with equipment suppliers to ensure as much recycled material as possible is used
• Recover: this can include simple operations such as regular litter collection as well as more advanced procedures, such as the use of tracking devices on key equipment that is at risk of being lost
• Refuse: where possible, the paper recommends avoiding the use of equipment that is difficult to recycle, for example mixed-plastics materials.

The paper includes recommendations for ASC, to help guide the multi-stakeholder Technical Working Group (TWG) that has been set up to look at the waste management requirements in ASC standards. The TWG will discuss the white paper and ASC’s current waste management requirements. Recommendations will then be made to the ASC’s Technical Advisory Group (TAG), a multi-stakeholder group of experts from industry, NGOs and academia, for comment, approval, and potential inclusion in ASC’s upcoming Aligned Standard, covering all ASC certified species.

The White Paper can be found on the Plastics page of the ASC website.

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