Storms creating fish farming ‘ghost gear’, says ASC
Extreme weather is one of the major causes of plastic ‘ghost gear’ from fish farms entering oceans and rivers and the increasing frequency and severity of tropical storms due to climate change could exacerbate the problem, a study published by the Aquaculture Stewardship Council (ASC) has said.
The warning is contained in a report, Marine Litter and Aquaculture Gear, that has for the first time classified the different causes of plastic waste from aquaculture and assessed the risks to different farming systems.
It was commissioned and published by ASC to provide scientific rigour and evidence for a planned update to ASC standards to include requirements on this issue, but also includes recommendations for the wider industry.
Deliberate discharge
The report 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.
“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.”
Poor waste management
The report says that while lost plastics from aquaculture and capture fisheries are often considered together, 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. The report 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.
Solutions to problem
“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 Hidalgo in a press release.
“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.”
ASC is the preferred certification scheme of the world’s biggest salmon farmer, Mowi, although a rule that until recently prevented farms being certified if they used loch-grown smolts meant that only one Scottish farm is currently ASC-certified.
More information on the report can be found here.
