Fish farms are source of 0.5 per cent of CO2 emissions
● New study finds climate impact of fish and shellfish similar to sheep
Fish farming around the world generates around the same amount of greenhouse gas emissions as the sheep industry, according to new international research.
Cultivation of fish and shellfish has reached record levels globally, with about 115 million tonnes produced annually.
Now, for the first time, researchers have calculated the impact of worldwide aquaculture on the climate.
The study, led by scientists from Scotland’s Rural College (SRUC), found the sector generates 263 million tonnes of carbon dioxide equivalent.
This amounts to almost 0.5 per cent of total man-made greenhouse gas emissions.
Analysis showed production of feed for farmed fish is one of the biggest sources of emissions in the process.
Beef and dairy cattle have the biggest environmental footprint across the livestock industry as a whole, responsible for around 5.0 gigatonnes of carbon dioxide equivalent each year. Sheep farming generates about 254 million tonnes.
Sruc’sdrmichaelmacleod, who led the project, said: “Global aquaculture makes an important contribution to food security and is also a driver of economic development.
“But to enable sustainable expansion of aquaculture, we need to understand its contribution to global greenhouse gas emissions and how it can be mitigated.
“While the emissions from fish farming are unlikely to reach the levels of, for example, beef farming, it is important for the industry to consider ways to reduce emissions, which can also improve financial performance.”
Aquacultureiswortharound £1 billion to the Scottish economy, with salmon the country’s top food export.
Scottish ministers have announced plans to double salmon production, which is currently around 160,000 tonnes per year, by 2030.
But persistent problems with fish health and environmental pollution have blighted its image in recent years.
Dr Macleod added: “There are lots of ways to reduce emissions, including developing genetically improved breeds suitable for lower feed conversion rates, improving health, using more precise feeding methods and improving onfarm energy efficiency.
“Feed is the main source of emissions in most systems, so some of the reduction can be achieved before we even get to the fish farm, in the production of feed materials.”
Environmental campaigners and fisheries groups have hit out at the Scottish Government’s plans to expand the fish farming industry.
Many believe open-cage fish farms are harming the marine ecosystem, causing animal suffering and wiping out wild salmon populations.
They blame heavy use of chemicals and medicines to battle pests and diseases, as well as pollution from waste.