Diverse seas: status of threatened and declining features

This page hosts the Official Statistic in Development “Diverse seas: status of threatened and declining features”, published on 23 April 2025.

Official Statistic in Development Description
Scope of statistics
Involvement and contacts
Relation to other Official Statistics/National Statistics
Methods
Summary of results
Confidence in results and caveats
Accompanying resources
References

Official Statistic in Development Description

This statistic is being published as an Official Statistic in Development. It is designed to quantify the status of vulnerable marine features flagged for protection by summarising published status assessment results.
This statistic has been designed to feed into the C6 indicator which is part of the Outcome Indicator Framework – a suite of indicators describing environmental change relating to the ten goals of the 25 Year Environment Plan
This statistic provides a high-level summary of published status assessments for listed features: status assessments for features on the OSPAR List of Threatened and/or Declining Species and Habitats (T&D List) alongside state chapters of the OSPAR Quality Status Report (QSR; 2023) thematic assessments for benthic habitats, marine birds, marine mammals and fish; and Annex I habitats and Annex II, IV and V species assessments under Article 17 of the Habitats Directive. The Article 17 reporting requirement has since been translated into the Habitats Regulations which the UK is expected to report on again in 2028.
The OSPAR status assessments, incorporated in this indicator, were undertaken between 2019 and 2023. The Article 17 assessments were undertaken in 2007, 2013, and 2019. Summarised results are presented in this statistic. Trends are described for the Article 17 dataset, where available.
This statistic is being published as “In Development.” This will allow JNCC to seek feedback and allow further development as appropriate. This statistic is a summary of published status assessments which follow standardised methodological approaches. This ensures the confidence and quality of the underlying dataset. Opinions and feedback will be sought on the summarisation approach to ascertain the accuracy and applicability of this indicator, and to ensure it is of sufficient quality. The statistic will be deemed sufficient quality once it fully meets the needs of the OIF C6 indicator.
The frequency of updates to this indicator will be decided as part of the ongoing evaluation of this indicator. Future updates are dependent on the frequency of publication of the underlying datasets and assessment cycles.
Further information on this statistic and its development plan are included in the accompanying methodological background document.

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Scope of statistics

The statistics are presented for the UK, encapsulating marine and coastal features, including a high-level summary of published condition assessments and trends (where available).

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Involvement and contacts

The statistic was produced by JNCC, in consultation with Defra, as part of development of an indicator for the Outcome Indicator Framework.
Quality assurance was completed by JNCC.
The data are published as a JNCC Official Statistic in Development. If you have any queries or feedback, please contact us.

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Relation to other Official Statistics/National Statistics

The statistic presented here has been designed for the Outcome Indicator Framework, which is a suite of indicators describing environmental change in relation to the ten goals of the UK government’s 25 Year Environment Plan.
This statistic draws on assessments published via OSPAR’s Intersessional Correspondence Group on the Protection of Species and Habitats (ICG-POSH); and UK relevant assessments of marine and coastal features which were published under the Article 17 UK Habitats Directive Reporting process. The Article 17 reporting requirement has since been translated into the Habitats Regulations.
The UK Biodiversity Indicators for the Status of Threatened Habitats and Species of European importance) utilises the same underlying dataset derived from the Article 17 reporting, but does not separate marine and coastal habitats and species. The “Diverse seas: status of threatened and declining features” statistic presents only a marine and coastal narrative.

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Methods

This statistic incorporates two datasets: UK-relevant status assessments published as part of the OSPAR QSR (OSPAR, 2023); and marine and coastal features assessments published as part of the Article 17 UK Habitats Directive feature reports (JNCC, 2019).
The OSPAR dataset analysed here is based on the OSPAR List of Threatened and/or Declining (T&D) Species and Habitats, representing features in need to priority protection.
The Article 17 reporting process assesses the Conservation Status of Annex I habitats and Annex II, IV and V species for which the UK has conservation responsibilities.
The methodologies used to determine status in the underlying datasets is described in detail within the source publications (JNCC, 2019; OSPAR, 2023).
The two datasets were analysed separately in this statistic.
For the OSPAR dataset, this statistic summarises status assessment results made within OSPAR Region II (Greater North Sea) and Region III (Celtic Seas). These Regions are most closely aligned with UK waters but incorporate data from outside of the UK. Under OSPAR reporting, assessments conclude whether a feature is in a Good, Poor or Unknown status. The total number of features in each associated status, within each category (habitats, fish, marine mammals, birds and reptiles) was calculated and summarised graphically. Where no status assessment was conducted for a feature it was categorised as ‘Not Assessed.’
OSPAR status assessments were undertaken between 2019 and 2023. For the purposes of this statistic, these are considered a single dataset and summarised accordingly.
For the Article 17 dataset, the conservation status of coastal habitats, marine habitats, marine mammals and marine reptiles are summarised here. The two species of maerl assessed under Article 17 were combined as a single habitat feature. Under Article 17 reporting there are also a number of vagrant species; however, these have been excluded from this analysis.
There have been three assessments of features made under Article 17 Reporting in 2007, 2013, and 2019.
Under Article 17 reporting, assessments must conclude whether a feature is in a Favourable, Unfavourable-Inadequate, Unfavourable-Bad or Unknown conservation status.
A summary of these results has been presented graphically for each year, where the total number of features in each status classification within each feature category (coastal habitats, marine habitats, marine mammals and reptiles) are calculated and summarised. It should be noted that three datapoints are not sufficient to accurately infer change over time.
However, separate trend assessment were conducted within each time point within the Article 17 reporting process to determine if the habitat is Improving, Declining, Stable or Unknown.
Article 17 reporting results from 2019 represent the most accurate analysis of trend. For this time point, a graphical summary has been presented here to report status and trend together. Categories were combined for ease of representation and reporting – for example, a feature with Unfavourable-Inadequate status and Declining trend, and Unfavourable-Bad status and Declining trend were combined to form the category Unfavourable Declining.
Results from both the OSPAR and Article 17 datasets were described and tabulated to represent a high-level summary. The proportion of features in each status category were also calculated for each dataset, where appropriate.
Further information on the methodological approach is detailed in the accompanying methodological background document.

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Summary of results

The majority of OSPAR listed threatened and / or declining features were in Poor status (Figure 1). In Region II (Greater North Sea), 23 out of 28 assessed features (82%) were in Poor status. In Region III (Celtic Seas), 23 out of 27 (85%) assessed features were in Poor status. Only three assessed features were in Good status in Region II (spotted ray, thornback ray and roseate tern), and only one assessed feature was in Good status in Region III (thornback ray/skate) (Figure 1).

Figure 1: Status of UK relevant OSPAR Threatened and/or Declining Species and Habitats across OSPAR Regions II (Celtic Seas) and Region III (Greater North Sea), within each feature group (birds, fish, habitats, invertebrates, marine mammals, and reptiles).

For the Article 17 listed marine and coastal features, the majority of marine and coastal habitats were classified as Unfavourable across all three reporting periods (82% of all listed habitats in both 2007 and 2013, and 94% in 2019; Figure 2). Due to changes in methodologies between years, and the limited number of datapoints, inferences of differences and trends should be made with caution. However, trend assessments were conducted as part of Article 17 reporting, for each feature within each year of assessment. Due to methodological changes in 2019 reporting, the trends derived from 2019 provide the most accurate and up-to date representation of trend in feature status.

In the latest (2019) assessment, the majority of all listed habitats features – 16 out of 17 (94%) – were in Unfavourable-Inadequate or Unfavourable-Bad status (Figure 3). Of these, three (18%) had a Declining trend and for the remainder, the trend was either Stable or Unknown (Figure 3). No features categorised as Unfavourable in 2019 had an Improving trend.

For the species, a greater number of marine species were classed as Unknown in 2019 compared with previous years (Figure 2). This is due to a change in methodology. The only species in Favourable status was the grey seal, and the common seal was classed as Unfavourable-Inadequate with an Unknown trend. Only one species of reptile is assessed under Article 17 and this was classed as Unknown in all three time points (Figure 2).

Figure 2: Status of Article 17 listed coastal and marine features in the UK in 2007, 2013, and 2019 for each feature group (habitats (coastal and marine), marine mammals, and reptiles). It should be noted that there are changes in assessment methodologies between years.

Figure 3: Status of coastal and marine features assessed under Article 17 in the UK in 2019, summarising the number of features within each Conservation Status and Trend of habitat and species features. Unfavourable – Inadequate and Unfavourable – Bad have been combined

Table 1: Summary of OSPAR listed Threatened and/or Declining Species and Habitats and Article 17 listed features from the latest assessments. Summaries indicate number of assessed features only. Features without assessment have not been included.

Category	Greater North Sea (Region II) Threatened and / or Declining Species and Habitats overview	Celtic Seas (Region III) Threatened and / or Declining Species and Habitats overview	UK (Article 17) Article 17 listed features overview
Habitats (coastal and marine)	Eight out of nine OSPAR listed habitats assessed are in Poor status	Six out of seven OSPAR Listed habitats assessed are in Poor status	Sixteen out of seventeen Annex I habitats assessed are in Unfavourable status
Fish	Ten out of Thirteen OSPAR listed fish species assessed are in poor status	Twelve out of Fifteen OSPAR Listed habitats assessed are in poor status	Not assessed
Birds	Two out of three OSPAR listed bird species assessed are in poor status	Two out of two OSPAR listed bird species assessed are in poor status	Not assessed
Marine Mammals	Two out of two OSPAR listed marine mammal species assessed are in poor status	Two out of two OSPAR listed marine mammal species assessed are in poor status	One out of thirteen marine mammals assessed are in Unfavourable status, the status is Unknown for eleven species
Reptiles	One out of one OSPAR listed marine reptile species assessed are in poor status	One out of one OSPAR listed marine reptile species assessed are in poor status	Status is Unknown for the only marine reptile assessed
Invertebrates	Listed marine invertebrate species were not assessed	Listed marine invertebrate species were not assessed	Not assessed

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Confidence in results and caveats

The underlying assessments follow standardised methodological approaches published as part of existing assessments.
The methodologies used in this statistic to summarise published status assessments represent a simple, high-level analysis and presentation of trends. This type of assessment is not completed within the underlying datasets, but is an alternative representation of results framing a UK marine and coastal narrative. Therefore, the messages are not expected to diverge from the underlying assessments, and there is a high level of confidence in the results presented.
Regarding the OSPAR dataset, it should be noted that OSPAR Regions extend beyond UK waters and encapsulate datasets from outside the UK. It was not possible to disaggregate UK only datasets for the purposes of this statistic. The status reported as part of this statistic is representative of each OSPAR Region, and not specifically for the part of the Region that is within UK waters.
Regarding the Article 17 dataset, as this is published every six years, there are limited data points to inform an accurate trend. Furthermore, there were methodological differences in assessment for both habitats and species in 2019 which resulted in changed status for multiple habitats and species (see JNCC, 2019 and The National Archives website for more information). In 2019, for marine mammals, a revised approach was used to handle limited data and interpret guidance on setting Favourable Reference Values. For habitats, the method used to determine status and trend was altered. The latest (2019) datapoint, represents the most accurate narrative of status and trend, and caution is advised when comparing assessments to previous years.

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