​​​Key message

The indicator threshold value is based on estimated volumes of oil introduced to the Baltic Sea as illegal discharges of oil. The volume of oil is considered to be the most relevant metric to evaluate the effect on the marine environment from oil spills.

In the assessment period of 2011-2015 the estimated annual average volume of oil exceeded the threshold value in the Bothnian Bay, The Quark, The Bothnian Sea, The Åland Sea, the Eastern Gotland Basin, the Kiel Bay and the great Belt. The threshold value is defined based on a modern baseline defined by a reference period 2008-2013 when the estimated volume of oil was considered to be at a historically low level.

Both the number- and the size of illegal oil spills detected in annual aerial surveillance show decreasing trends in all sub-basins. This shows that the measures implemented in recent years have been successful in decreasing the pressure on the environment caused by oil spills. Oil spills are principally detected along the main shipping routes.


Key message figure 1.png

Key message figure 1: Status assessment results based evaluation of the indicator 'operational oil spills from ships'. The assessment is carried out using Scale 2 HELCOM assessment units (defined in the HELCOM Monitoring and Assessment Strategy Annex 4). Click to enlarge.


Aerial surveys of oil spills have been carried out by Contracting Parties of HELCOM for several years with standardized methods, annually covering nearly the entire Baltic Sea. The confidence of the indicator evaluation is therefore considered to be high. However, decline in flight hours in recent years might have a negative effect on the confidence in the future.

The indicator is applicable in the entire Baltic Sea area.

Relevance of the core indicator

Oil is an important commodity in the region with large volumes being transported across the Baltic Sea and constitutes the main fuel of the absolute majority of ships in the region. Oil and other petroleum products end up in the marine environment through intentional introduction or due to negligence, often as oil in bilge water or via dumping of waste oil or due to release during an accident. All oil spills pose a significant threat to water birds and other marine animals, both acute death and chronic toxic effects are known.

The indicator evaluates the sustainability of handling of oil and petroleum products in the Baltic Sea region, as sustainable activities should ensure minimal number of spills and volume of oil introduced to the marine environment.

Policy relevance of the core indicator

BSAP Segment and Objectives MSFD Descriptors and Criteria​
Primary link

​Enforcement of international regulations – no illegal discharges​

Annex III – Contamination by hazardous substances; introduction of synthetic compounds

Secondary link

​8.2. Effects of contaminants​

Other relevant legislation: IMO MARPOL Convention Annex I, Helsinki Convention including Annex VII ​​


Cite this indicator

HELCOM (2017) .Oil-spills affecting the marine environment. HELCOM core indicator report. Online. [Date Viewed], [Web link].

ISSN 2343-2543

Download full indicator report

HOLAS II component - Core indicator report – web-based version July 2017 (pdf)