C1: Clean seas: marine litter

Short Description

This indicator of clean seas shows changes in the amount of litter in the marine environment, including litter on beaches, on the seafloor and floating litter. Beach litter surveys are completed annually or quarterly and cover a representative number of beaches. Data from benthic trawl surveys, typically carried out for fish stock assessments, are used to monitor the amount of litter on the seafloor. After each tow, all litter items are emptied from the net and counted and classified. Beached fulmars or individuals accidently killed are collected as part of a monitoring programme in the Greater North Sea to assess the plastics found in their stomachs. Fulmars forage exclusively at sea, generally at the surface of the water. The amount of plastic they ingest can be used as a proxy for the abundance of floating litter in their environment and how this is changing. Indicators for seafloor litter, beach litter and plastic found in Fulmar stomachs have been developed and expert groups are working to improve the data. Additional monitoring programmes are being developed to record the amount of microplastics in sediment and in biota.

Readiness and links to data

This indicator is not available for reporting in 2023 in a finalised form. A revised interim indicator is presented here that shows 3 aspects of litter in the marine environment: a) beach litter b) plastic in fulmar stomachs and c) seafloor litter.

The beach litter component of this interim indicator is drawn from the assessment of Marine litter, reported under the updated UK Marine Strategy Part One (2019).

Assessments of marine litter have also been conducted as part of the 2023 Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) Quality Status Report. The assessment of beach litter requires further consideration prior to being included in the Outcome Indicator Framework, however the revised assessment of seafloor litter has been incorporated into this indicator as part of the 2023 update.

An assessment of plastic particles in fulmar stomachs has also been conducted, however we have in addition incorporated more recent data, published in the latest research report from Wageningen University to Defra (Project code ME5227).

Further development of this indicator is required, and the indicator’s format will evolve.

Indicator components

Figure C1a: Items of litter per 100m of beach, UK, 2008 to 2015

Table C1a: Items of litter per 100m of beach, UK, 2008 to 2015

Year Celtic Seas Greater North Sea
2008 326.30 174.40
2009 329.80 140.00
2010 309.30 150.90
2011 240.00 151.50
2012 286.30 177.70
2013 230.70 251.90
2014 290.70 240.90
2015 367.60 282.10

Trend description for C1a

Between 2008 and 2015, the average total abundance of beach litter items per 100 metres of coast varied considerably around the UK with greater quantities being recorded in the Celtic Seas than in the Greater North Sea. After showing some decrease from 2009 to 2011, beach litter levels in the Celtic Seas in 2015 had risen to greater than the 2008 levels. In the Greater North Sea, there was an increase in beach litter levels between 2008 and 2015.

Water currents, weather conditions, and prevailing wind conditions can have an influence on the deposition and retention of beach litter and therefore beach litter abundance. In all beach litter regions, the majority of litter items were made of plastic (including polystyrene). Plastic fragments are the most commonly found type of litter item, followed by food and drinks packaging, sewage related debris and then smaller amounts of fishing-related litter.

Assessment of change

The time series for interim C1a indicator Items of litter per 100m of beach runs from 2008 to 2015 which is not yet long enough to produce an assessment for medium and long-term time periods. Little or no change was observed in the Celtic Seas region over the most recent 5 years for which trends can be assessed (2009 to 2014), but an increase (or deterioration) was observed in the Greater North Sea region.

The assessment results reported here are not directly comparable with other analyses published elsewhere that use different methodologies to explore these indicators or are based on alternative datasets or timeseries.

Change since 2018 cannot be assessed as the data currently presented here predate the 25 year environment plan.

Further information on this assessment, along with details on the methodology, is provided in the Assessment background. Summaries by 25 Year Environment Plan goal and information on indicator links are presented in the Assessment results.

Table C1a: Assessment of change

Component Subcomponent Period Date range Percentage change Smoothing function Assessment of change
C1a Celtic Seas Short term 2009 to 2014 -9.61 Loess Improvement
C1a Celtic Seas Medium term N/A N/A N/A Not assessed
C1a Celtic Seas Long term N/A N/A N/A Not assessed
C1a Greater North Sea Short term 2009 to 2014 73.74 Loess Deterioration
C1a Greater North Sea Medium term N/A N/A N/A Not assessed
C1a Greater North Sea Long term N/A N/A N/A Not assessed

Assessment categories for indicator C1a were assigned based on smoothed data, so percent change figures in table C1a may differ from unsmoothed values quoted elsewhere. Percent change refers to the difference seen from the first to last year.

Figure C1b: Percentage of sampled fulmars having more than 0.1g of plastic in their stomach, Greater North Sea, 2004-2008 to 2017-2021

Table C1b: Percentage of sampled fulmars having more than 0.1g of plastic in their stomach, Greater North Sea, 2004-2008 to 2017-2021

Time period Percentage
2004-2008 62
2005-2009 65
2006-2010 64
2007-2011 63
2008-2012 64
2009-2013 61
2010-2014 63
2011-2015 67
2012-2016 58
2013-2017 55
2014-2018 49
2015-2019 48
2016-2020 45
2017-2021 45

Trend description for C1b

From 2004 to 2014 approximately 60% of surveyed (beached) fulmars in the Greater North Sea region were found to have more than 0.1 grams of plastic (the threshold level used in the OSPAR target definition) in their stomachs. This reflects the abundance of floating litter in their environment. Since the period 2010 to 2015, there has been a decline in the proportion of surveyed fulmars with more than 0.1g of plastic in their stomachs, to 45% in the period 2017 to 2021.

Assessment of change

A decrease (or improvement) in the percentage of sampled fulmars which have more than 0.1g of plastic in their stomach was observed over the short, medium, and long-term time periods. This assessment does not consider whether any improvement is on a sufficient scale for meeting targets.

Change since 2018 has also been assessed. A decrease (improvement) in the fulmar indicator was observed since 2018. However, this is based on only 4 data points so should be considered as indicative and not evidence of a clear trend.

The assessment results reported here are not directly comparable with other analyses published elsewhere that use different methodologies to explore these indicators or are based on alternative datasets.

Further information on this assessment, along with details on the methodology, is provided in the Assessment background. Summaries by 25 Year Environment Plan goal and information on indicator links are presented in the Assessment results.

Table C1b: Assessment of change

Component Subcomponent Period Date range Percentage change Smoothing function Assessment of change
C1b None Short term 2012-2016 to 2017-2021 -22.41 Rolling average Improvement
C1b None Medium term 2007-2011 to 2017-2021 -28.57 Rolling average Improvement
C1b None Long term 2004-2008 to 2017-2021 -27.42 Rolling average Improvement

Percent change refers to the difference seen from the first to last 5-year moving average in the specified date range.

Figure C1ci: Mean probability that benthic trawl surveys contain a litter item, expressed as a percentage, Greater North Sea and Celtic Seas, 2012 to 2019

Table C1ci: Mean probability that benthic trawl surveys contain a litter item, expressed as a percentage, Greater North Sea and Celtic Seas, 2012 to 2019

Year Celtic Seas Greater North Sea
2012 47.00 57.00
2013 49.00 67.00
2014 53.00 69.00
2015 43.00 59.00
2016 38.00 69.00
2017 40.00 76.00
2018 45.00 73.00
2019 43.00 75.00

Trend description for C1ci

In the Greater North Sea, there has been a gradual increase in the mean probability of a benthic survey containing litter, from 57% in 2012 to 75% in 2019. In the Celtic Seas, the mean probability of a survey containing litter has fluctuated around 45%, with a peak of 53% in 2014. More granular data is available for the latest year in the series (2019, C1cii), with the greatest probability of a benthic trawl survey containing litter being in the south and south-east Greater North Sea and the south-west Celtic Seas. Benthic trawl surveys in the north-west Greater North Sea and Celtic Seas have the lowest probability of containing a litter item.

Assessment of change

The time series for C1ci, mean probability that benthic trawl surveys contain a litter item, is from 2012 to 2019 which is not yet long enough to produce an assessment for medium and long-term time periods.

An increase (or deterioration) was observed in the Greater North Sea region, but a decrease (or improvement) was observed in the Celtic Seas region over the most recent 5 years for which trends can be assessed (2013 to 2018). However, it is important to note that assessment results reported here are not directly comparable with other analyses published elsewhere that use different methodologies to explore these indicators or are based on alternative datasets.

Further information on this assessment, along with details on the methodology, is provided in the Assessment background. Summaries by 25 Year Environment Plan goal and information on indicator links are presented in the Assessment results.

Table C1ci: Assessment of change

Component Subcomponent Period Date range Percentage change Smoothing function Assessment of change
C1ci Celtic Seas Short term 2013 to 2018 -16.30 Loess Improvement
C1ci Celtic Seas Medium term N/A N/A N/A Not assessed
C1ci Celtic Seas Long term N/A N/A N/A Not assessed
C1ci Greater North Sea Short term 2013 to 2018 16.47 Loess Deterioration
C1ci Greater North Sea Medium term N/A N/A N/A Not assessed
C1ci Greater North Sea Long term N/A N/A N/A Not assessed

Assessment categories for indicator C1ci were assigned based on smoothed data, so percent change figures in Table C1ci may differ from unsmoothed values quoted elsewhere. Percent change refers to the difference seen from the first to last year.

Image C1cii: Probability that benthic trawl surveys contain a litter item, expressed as a percentage, UK, 2019 (smoothed)

Trend description for C1cii

In the Greater North Sea, there has been a gradual increase in the mean probability of a benthic survey containing litter, from 57% in 2012 to 75% in 2019. In the Celtic Seas, the mean probability of a survey containing litter has fluctuated around 45%, with a peak of 53% in 2014. More granular data is available for the latest year in the series (2019, C1cii), with the greatest probability of a benthic trawl survey containing litter being in the south and south-east Greater North Sea and the south-west Celtic Seas. Benthic trawl surveys in the north-west Greater North Sea and Celtic Seas have the lowest probability of containing a litter item.

Assessment of change

No assessment of change is available for C1cii as this is a spatial representation of the most recent year's data presented in C1ci.

Indicator Metadata