Research over 25 years by a Suffolk-based world leader in marine science and technology has revealed changes in the composition of plastic litter that pollutes the UK's seas and coasts.

Eastern Daily Press: A Cefas map charting the plastic litter found in 2011. Image: CEFASA Cefas map charting the plastic litter found in 2011. Image: CEFAS

Experts from the Centre for Environment, Fisheries and Aquaculture Science (Cefas), which has laboratories at Pakefield, near Lowestoft, have found that the amount of plastic bags found on the UK's sea bed has decreased. Their findings suggest that efforts to tackle the marine litter challenge may be successful.

However, despite the reduction in the number of plastic bags recorded in an analysis of scientific surveys, the overall amount of litter has been maintained by an increasing amount of other plastic items, including fishing debris.

Widespread distribution of litter items, especially plastics, was found on the sea bed of the North Sea, the English Channel, the Celtic Sea and the Irish Sea. High variation in the abundance of litter items, ranging from none to 1,835 pieces per square kilometre of sea floor, was observed.

Plastic items such as bags, bottles and fishing-related debris were commonly observed across all areas. Over the entire 25-year period, which spanned from 1992 to 2017, 63pc of the 2,461 trawls contained at least one plastic litter item.

Cefas marine litter scientist Thomas Maes said: 'It is encouraging to see that efforts by all of society, whether the public, industry, non-governmental organisations or government to reduce plastic bags are having an effect.

'We observed sharp declines in the percentage of plastic bags as captured by fishing nets trawling the seafloor around the UK compared to 2010 and this research suggests that by working together we can reduce, reuse and recycle to tackle the marine litter problem.'

Cefas, which also has laboratories in Weymouth, Dorset, and port-based offices in Scarborough, Hayle and Plymouth, said that marine litter is a global challenge, with increasing quantities documented in recent decades. The distribution and abundance of marine litter on the sea floor off the UK's coasts were quantified during 39 independent scientific surveys conducted during the 25-year period.

There was no significant timing trend in the percentage of trawls containing any or total plastic litter items across the long-term datasets. Statistically significant trends were observed only in specific plastic litter categories. Such trends were all positive except for a negative trend in plastic bags in the Greater North Sea - suggesting that behavioural and legislative changes could reduce the problem of marine litter within decades.

The paper is available at: https://doi.org/10.1016/j.scitotenv.2018.02.245.