Baltic Marine Environment
Protection Commission


Baltic Marine Environment
Protection Commission

HELCOM Explorer gives easy online access to follow implementing the Baltic Sea Action Plan

The recently updated online tool HELCOM Explorer allows to easily see how HELCOM cooperation bears fruit, and how the countries’ actions are being fulfilled when reaching the majority of their ambitious HELCOM targets and the ultimate goal: Baltic Sea in good ecological state.

The actions listed in the Explorer include the entire updated Baltic Sea Action Plan (2021), HELCOM Ministerial Meeting commitments from 2010 onwards as well as selected HELCOM Recommendations. The updated BSAP contains 199 concrete actions and measures addressing biodiversity, eutrophication, hazardous substances, and sea-based activities such as shipping and fisheries. In addition, it includes new actions on emerging or previously less highlighted pressures such as climate change, marine litter, pharmaceuticals, underwater noise, and seabed disturbance.

As most actions of the 2021 Baltic Sea Action Plan have a deadline years ahead, they now show red, Not accomplished, in the HELCOM Explorer.

The updated BSAP is also closely aligned with international and regional objectives such as the UN Sustainable Development Goals (SDGs), the targets of the Convention on Biological Diversity (CBD), or, for those of our Contracting Parties that are also EU members, the EU’s Marine Strategy Framework Directive (MSFD).  All actions are to be implemented by 2030 at the latest.

“As the HELCOM Explorer provides a comprehensive overview and a great amount of information on both joint and national actions, with easy filtering tools, it is quite a unique system in regional marine governance. Moreover, it is a very concrete indicator  of transparency for our stakeholders and to the broader audiences”, says Rüdiger Strempel, Executive Secretary of HELCOM.

Joint actions are carried out together by all HELCOM Contracting Parties, for example creating a new Recommendation, joint management guidelines, or assessments of environmental status. National actions are implemented at the country level, and they include e.g. incorporating the provisions of a HELCOM Recommendation into relevant national legislation or guidelines.

The Explorer allows for easy overview browsing, but also for more detailed filtering, according to the details of the actions in the Baltic Sea Action Plan such as segment, theme, or target year. The tool further provides information on why the action is needed (rationale), what pressures or activities are addressed by the action in question, and, for some, what is the potential effect of the measure to reduce pressures or improve the state of the Baltic Sea. All data is available for download.

The HELCOM Explorer tool to track the progress on the implementation of HELCOM commitments was first launched in 2016, and the interface was updated in 2020.

The reporting on the implementation of the joint actions is done by relevant HELCOM Working Groups and the reporting on the national actions by the countries. The first reporting on the implementation of actions in the 2021 BSAP is planned to take place in 2025, followed by the second reporting round in 2029.


Mock Employee
Laura Kaikkonen

Project Researcher

Mock Employee
Susanna Kaasinen

Associate Professional Secretary

About the Baltic Sea Action Plan (BSAP)

The Baltic Sea Action Plan (BSAP) is HELCOM’s strategic programme of measures and actions for achieving good environmental status of the sea, ultimately leading to a Baltic Sea in a healthy state.

Initially adopted by the HELCOM Contracting Parties in 2007, the 2021 BSAP is based on the original plan and maintains the same level of ambition. It also retains all actions previously agreed on that are still to be implemented, while, in addition, includes new actions to strengthen the existing efforts and tackle emerging concerns.

Guided by the HELCOM vision of “a healthy Baltic Sea environment with diverse biological components functioning in balance, resulting in a good ecological status and supporting a wide range of sustainable economic and social activities”, the updated BSAP is divided into four segments with specific goals: biodiversity, eutrophication, hazardous substances and sea-based activities.

About HELCOM Recommendations

One of the most important duties of the Helsinki Commission is to make Recommendations on measures to address certain pollution sources or areas of concern. Since the beginning of the 1980s HELCOM has adopted some 260 HELCOM Recommendations for the protection of the Baltic Sea. The implementation of various HELCOM recommendations by the HELCOM Contracting Parties plays an important role in achieving the objectives of the Baltic Sea Action Plan. The HELCOM Explorer covers the reporting on the implementation status of selected HELCOM Recommendations.


The Baltic Marine Environment Protection Commission – also known as the Helsinki Commission (HELCOM) – is an intergovernmental organization (IGO) and a regional sea convention in the Baltic Sea area, consisting of ten members: the nine Baltic Sea countries Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia and Sweden, plus the European Union. A platform for environmental policy making at the regional level, HELCOM works for a healthy Baltic Sea. Its mandate stems from a regional treaty, the Helsinki Convention, whose implementation it oversees. The HELCOM Secretariat is located in Helsinki, Finland.

On 16 May 2021, we’re celebrating the International Day of the Baltic Harbour Porpoise

The “International Day of the Baltic Harbour Porpoise” is celebrated on the third Sunday in May of each year, to raise awareness of the alarming situation of the harbour porpoise, a rather unique marine mammal. And indeed: it is the only cetacean that calls the Baltic Sea its permanent home. 

In the Baltic Sea region, harbour porpoises (Phocoena phocoena) were actively hunted until the end of the 19th century. Although this practice has stopped, their populations declined rapidly since the middle of the 20th century. They are now heavily impacted by other human pressures, most notably by-catch in fishing gear, but also pollutants, habitat deterioration and disturbance caused by underwater noise. 

The “International Day of the Baltic Harbour Porpoise” (IDBHP) was declared an international observance by the Agreement on the Conservation of Small Cetaceans in the Baltic, North East Atlantic, Irish and North Seas (UNEP/ASCOBANS).

Read more about the harbour porpoise:


Watch the video address by Rüdiger Strempel on the occasion of the “International Day of the Baltic Harbour Porpoise” 

The BSAP update is well on track at HELCOM 42-2021, the annual meeting of the Helsinki Commission

Screenshot of the HELCOM 42-2021 online meeting

More milestones on the now imminent update of the Baltic Sea Action Plan (BSAP) were reached during the 42nd Meeting of the Helsinki Commission (HELCOM 42-2021), held online from 17 to 18 March 2021, keeping the work on the new plan well on track and within the planned schedule. 

second full draft of the updated Baltic Sea Action Plan (BSAP) was presented at the meeting. Further refinements will now take place in the various HELCOM bodies tasked with the drafting of the update. The BSAP, in addition to actions and measures, will now also include a list of environmental hotspots that will need to be resolved as part of the plan’s implementation.

The updated Baltic Sea Action Plan (BSAP) is due to be adopted during the next HELCOM Ministerial Meeting which will be hosted by Germany and is scheduled to take place on 20 October 2021 in Lübeck, Germany. HELCOM Ministerials take place every three years and bring together the competent Ministers from the HELCOM countries and the EU Commissioner for the Environment.

Several key processes and documents due to be adopted alongside the updated BSAP and serving as supporting tools to reach its objectives were also green-lighted for further development at HELCOM 42-2021. These include the draft Baltic Sea Regional Nutrient Recycling Strategy and the draft Regional Maritime Spatial Planning Roadmap 2021-2030.

The HELCOM Contracting Parties also approved, in principle, the draft HELCOM Regional Action Plan on Underwater Noise. Due to be adopted in June 2021 by the HELCOM decision-makers pending final refinements, the plan will contain a set of regional and national actions for the monitoring and management of man-made underwater noise in the Baltic Sea.

On hazardous substances, the Contracting Parties agreed to modernize the overall HELCOM framework dealing with the issue, to allow a faster and more efficient response to emerging challenges caused, for instance, by a relentless introduction of new chemicals used in industry and consumer products. The new strategic direction will also enable a better understanding of the full diversity of sources and pathways of contaminants to the Baltic Sea.

Serving as a basis for this decision, HELCOM had, earlier in 2020, drafted a strategic regional policy document on hazardous substances, in cooperation with the Stockholm University Baltic Sea Centre and with the support of the Swedish Agency for Marine and Water Management (SwAM).

In a bid to improve response to spills in the Baltic Sea, the Contracting Parties also adopted the revised HELCOM Response Manual as well as the draft Multi-regional Marine HNS Response Manual which will replace the current HELCOM Response Manual Volume 2. Both manuals are primarily intended for the authorities dealing with transboundary maritime incidents affecting the waters of several countries and are intended to facilitate the coordination of international response efforts.

At HELCOM 42-2021, the revised HELCOM Recommendation 31E/6 Rev on integrated wildlife response planning in the Baltic Sea area was also adopted. The Recommendation lays out options and strategies for the response to maritime accidents such as oil spills in order to guarantee a swift mobilization of resources to safeguard and attend to affected wildlife.

To improve the protection of habitats and species in the Baltic Sea, the HELCOM Contracting Parties further agreed to cooperate with FAO and IUCN in organizing a regional HELCOM workshop on “other effective area-based conservation measures” (OECMs) in early 2022. OECMs are geographically defined areas other than marine protected areas (MPAs) but that have a positive effect on the conservation of biodiversity.  

The meeting was also an opportunity for the HELCOM Executive Secretary, Rüdiger Strempel, to highlight the achievements of the organization in 2020, noting, in his statement, that “despite the unprecedented challenges posed by the Corona pandemic, HELCOM work progressed largely as planned in 2020.” The HELCOM Activities report for the year 2020 was also presented on the same occasion.

The outcomes of the recently held HELCOM Stakeholder Conference 2021 “Practically Implementing Ecosystem-Based Management” (HSC2021) were also presented. In addition to being one of the HELCOM Voluntary Commitments to the UN Ocean Conference 2021, the HSC2021, held as an online workshop, also offered the possibility to gather considerations on Ecosystem-Based Management (EBM) from stakeholders as possible input for the BSAP update process, the HELCOM Science Agenda and HELCOM’s future work on implementation on the ecosystem approach. The results of the HSC2021 are now due to be forwarded to the relevant HELCOM groups for further consideration. 

The HELCOM 42-2021 meeting was chaired by the Chair of the Helsinki Commission, Lilian Busse, Germany and the Vice-Chair of HELCOM 2020-2021, Mr. Johannes Oelerich, Germany. Attended by all Contracting Parties, it was also the first official meeting for the newly appointed Heads of Delegation of Lithuania and Poland and, Ms. Agnė Lukoševičienė from the Ministry of Environment of Lithuania, respectively Ms. Ewelina Fałowska from the Ministry of Infrastructure of Poland. 

HELCOM updates its online tool for assessing the risk of introduction of alien species via ballast water

Aliens in the Baltic Sea? Not if shipping managers utilize the free online tool developed by HELCOM and OSPAR to minimise the introduction of non-indigenous species (NIS, also known as alien species) via the ballast water of ships. The tool has recently been updated as part of the Interreg COMPLETE project

“The updated tool now makes it even easier to evaluate the risk of introduction of alien species by ships traveling between two ports in the HELCOM-OSPAR area,” said Manuel Sala-Pérez, the COMPLETE project’s coordinator at HELCOM.  

Alien species often travel with ballast water in ships, being sucked up into ships in one port and then discarded in another where they could potentially proliferate, take over habitats and disrupt the food chain and existing biodiversity. “For fragile marine ecosystems such as the Baltic Sea, NIS can be a serious issue,” cautioned Sala-Pérez. 

The free online tool, the so-called Ballast Water Exemptions Decision Support Tool, assesses the risk of introduction of NIS in a simple way, yet based on the latest scientific knowledge on the occurrence and distribution of species as well as the environmental characteristics of each port. 

“The online tool is now more user-friendly and contains improved GIS functionalities and data visualisations,” said Sala-Pérez, adding that it also includes updates to the underlying technology such as databases and algorithms. “It should be the go-to tool for whoever is dealing with ballast water management in the Baltic and North Seas.”  

COMPLETE is an EU INTERREG Baltic Sea Region project aimed at minimizing the introduction and spread of harmful aquatic organisms and pathogens by shipping, notably via ballast water and biofouling. In the project, HELCOM led the activity tasked with updating the NIS online tool. 

HELCOM further took part in the development of a proposal for a Baltic Sea Biofouling Roadmap and a HELCOM monitoring programme on NIS. It also participated in the review process of the HELCOM-OSPAR Joint Harmonised Procedure on ballast water exemptions, particularly on risk assessments of NIS introductions, and the update of the selection criteria for target species.

HELCOM launches its BLUES project to support attaining good environmental status in the Baltic Sea

Good environmental status, or GES, and a Baltic Sea in healthy state are at the core of the HELCOM BLUES project that was officially launched online from 2 to 4 February 2021. Co-funded by the European Union and led by HELCOM, the Baltic-wide effort will run through 2022, for a total period of two years. 

To help attaining GES in the Baltic Sea, the HELCOM BLUES project will support the development of new and regionally coordinated measures addressing various pressures affecting the sea. It will also back assessments of the state of the Baltic through improved monitoring, notably on biodiversity, marine litter and underwater noise. 

“HELCOM BLUES is an opportunity to fill the gaps we have identified so far during our journey towards good environmental status in the Baltic Sea,” said Jannica Haldin, the overall project manager and HELCOM senior expert dealing with biodiversity matters. HELCOM is concluding its first analysis ever of the sufficiency of measures (SOM) currently in place for easing the pressures on the sea, with the results expected to inform the work of the new project.

“GES is a Baltic-wide objective, and we can only achieve it through a collective effort and regional cooperation,” said Jana Wolf, the HELCOM project coordinator in charge of the day-to-day operations of HELCOM BLUES. In total, 14 partners and seven subcontractors  with various backgrounds such as policy, research, academia or civil society and hailing from six Baltic Sea countries are involved in the project.

“The project also closely links to the big processes related to GES in the Baltic such as the EU Marine Strategy Framework Directive (MFSD), the HELCOM Baltic Sea Action Plan (BSAP) and the next Holistic Assessment of the Baltic Sea (HOLAS III),” said Haldin.

On the MFSD, the specific requests expressed by the EU in its initial call for project proposals – which is at the origin of HELCOM BLUES – were taken into account, notably on the development of effective regional measures to reduce existing pressures to the Baltic Sea, with a focus on biodiversity, marine litter and underwater noise. Furthermore, all results of the project will be made accessible to the Baltic Sea countries who are also EU member states to support their national obligations under the MSFD.

The outcomes of the project will also underpin the implementation of the updated Baltic Sea Action Plan that is due to be adopted in October 2021 by providing monitoring data and guidance on the implementation of measures. 

It will also support HELCOM’s next Holistic Assessment of the Baltic Sea (HOLAS III) covering the period of 2016 to 2021. The project will notably provide improved assessment data, for instance by improving the capacity for biodiversity reporting and the development of indicators on marine litter and underwater noise. 

Project activities

The project is built around seven activities:

  • Activity 1 – Analyses to support effective regional measures
  • Activity 2 – Improved regional assessment of biodiversity  
  • Activity 3 – Support for, and harmonisation of, regional work on MSFD Descriptor 10 (marine litter)  
  • Activity 4 – Support for, and harmonisation of, regional work on MSFD Descriptor 11 (underwater noise) 
  • Activity 5 – Data accessibility 
  • Activity 6 – Dissemination 
  • Activity 7 – Project Coordination 

More info

HELCOM publishes maps on fish habitats

HELCOM just published several maps on essential fish habitats, publicly available online on HELCOM’s Map and Data service. The maps were produced under the recently concluded Pan Baltic Scope project on maritime spatial planning (MSP) in the Baltic Sea region and to which HELCOM was a partner.

The maps show potential spawning areas of cod, sprat and herring, which are the commercially most important fish species in the Baltic Sea region, as well as key areas for European and Baltic flounder, perch and pikeperch. 

“With the maps on essential fish habitats, we now have another tool at our disposal to identify and evaluate marine areas of greater ecological importance,” said SLU Aqua’s Lena Bergström who was responsible for this component within the Pan Baltic Scope project. 

Combined with corresponding data for other ecosystem components, the maps on essential fish habitats can be used to identify regions of high ecological value and areas which have the potential to deliver various essential ecosystem services.

The maps can be found under Biodiversity section of the HELCOM Map and Data service: 

The maps can also be downloaded as raster files from the HELCOM Metadata catalogue.

The Pan Baltic Scope project was co-founded by the European Maritime and Fisheries Fund of the European Union. In the project, HELCOM notably collaborated on a data sharing activity to support regional cooperation and transboundary coherence in MSP which lead to the development of BASEMAPS, a web-based tool showing decentralized MSP data through open standard services.

Sea trout are back in Lithuanian river after successful restoration under the RETROUT project

©Piotr Wawrzyniuk –

Sea trout are reproducing again in parts of the Smeltalė river in Lithuania after a successful restoration exercise under the Baltic-wide RETROUT project.

“We counted 13 new sea trout nests within only two months after the restoration work was finished,” said Nerijus Nika from Klaipeda University, one of the partners responsible for the Lithuanian river restorations within RETROUT, further noting that the specifically created reproduction sections, or spawning habitats, were all intensively used by sea trout. The restoration work was completed in September 2019.

RETROUT carries out a number of river restoration demonstration cases in the project partner countries to improve the condition of sea trout populations. 

“For viable and healthy sea trout populations, we need healthy and accessible rivers. Unfortunately, many rivers potentially suitable for sea trout aren’t yet in the condition we’d like them to be,” said Henri Jokinen, the RETROUT project manager at HELCOM.

In Lithuania, the rehabilitation started with the creation of a system of meandering shallow ponds in an area of the Smeltalė river previously purposed as a surface flow treatment wetland for improved water quality. 

Since its construction 20 years ago, the wetland hadn’t been maintained, accumulating excessive sediments from defaulting sedimentation ponds as well as suffering from excessive vegetation on its banks. 

In addition, a 500 m section was modified in the Smeltaitė stream, a main tributary of Smeltalė river, using stones, gravel and logs to create three 50 m long spawning and juvenile rearing habitats. 

“According to local experts, such habitats are spawning hot spots for salmonids and lampreys in lowland streams of Lithuania,” said Jokinen. Indeed, all three created spawning habitat sections were intensively used by sea trout only two months after completion. 

In the Smeltaitė stream, the two biggest trout nests – of 7,5 m2 and 10 m2 – were found in the restored stretch, in habitats pre-evaluated to be of high priority for sea trout females. One of these sites was constantly occupied for 1.5 month by up to five different trout, a rather unusual spawning behaviour. 

With special focus on sea trout, the RETROUT project seeks to promote and develop sustainable coastal fishing tourism in the Baltic Sea region. RETROUT initiated 15 restoration cases in coastal rivers of Estonia, Lithuania, Latvia, Poland and Sweden. Measures under the project cover fishways, biotope restorations, water quality improvement, and dam removal plans. 

In the RETROUT project, HELCOM leads the work package on Assessment of status and management of sea trout rivers and stocks which focuses mainly on the ecological aspect of trout fishing, notably through assessing fish stock and river habitat status, and by evaluating river restoration practices to improve trout populations. 

The main results will be published as an assessment report and as a toolbox of best practices and guidelines for river restoration in the Baltic Sea. 

“In addition to improving the actual condition of a river, the experience we get from these demonstration cases will help us to develop the ‘Guidelines for river restoration best practices in the Baltic Sea region,’ another major outcome of the project,” said Jokinen.

The restoration of the Smeltalė river was conducted by the Klaipeda District Municipality Administration, with technical and scientific support from the Klaipeda University. 

Photos from Smeltalė river, Lithuania. © Nerijus Nika

Two sea trout in their newly restored habitat. © Tomas Ruginis

HELCOM publishes report on noise sensitivity of animals in the Baltic Sea

The recently published HELCOM report “Noise sensitivity of animals in the Baltic Sea” shows how marine mammals, fish and diving birds may react to underwater sound in the Baltic Sea.

“In the past few years, HELCOM has been keen on understanding how underwater noise impacts the different Baltic Sea animal species,” said Marta Ruiz, the HELCOM expert on underwater noise and co-author of the report.

In 2013, the HELCOM members had agreed in Copenhagen that “the level of ambient and distribution of impulsive sounds in the Baltic Sea should not have negative impact on marine life.” The report is a direct response to that announcement.

A first at the Baltic Sea scale, the report identifies species which may be impacted by noise, based on the hearing sensitivity, threat status and commercial value of the animals as well as the impact of noise and the availability of data.

Seals and harbour porpoises are particularly affected by noise due to their high hearing sensitivity. These species rely heavily on hearing throughout their entire life such as for geolocation, communicating or mating, and excessive noise may lead to behavioural changes and physiological stress.

According to the report, “spatial distribution of a species is important when considering the potential risks of impacts from noise.” The report therefore provides a prioritized list of noise sensitive Baltic Sea species and highlights their distribution, to map biologically sensitive areas which also consider periods of biological significance for those species. These areas and the list of species are expected to be updated whenever more data becomes available.

Supported by the HELCOM coordinated and EU co-financed BalticBOOST project, the report is part of the flagship publication series of HELCOM, the Baltic Sea Environment Proceedings (BSEP) that have been running since the ratification of the first Helsinki Convention in 1980.

The HELCOM report “Noise sensitivity of animals in the Baltic Sea” is now publicly available as BSEP n° 167.

Halfway there: RETROUT project for promoting sustainable fishing and viable fish stocks convenes for its mid-term meeting

The project had its mid-term meeting in Gdańsk, Poland from 8 to 9 May
2019, looking at achievements so far and the next steps to be taken.  “Work is progressing according to plans,
although some challenges need to be tackled to reach the final goals by the end
of the project in fall 2020,” said Håkan Häggström, the RETROUT from the County Administrative
Board of Stockholm, Sweden. With special focus on sea trout, RETROUT
seeks to promote and develop sustainable coastal fishing tourism in the Baltic
Sea region. Fostering thriving fish populations is a key approach of the
project, through enabling healthy and accessible river habitats for the natural
reproduction of sea trout that will eventually lead to a larger stock size. In the countries where it operates, the
project also carries out a number of river restoration initiatives to improve the
condition of sea trout populations. For example, one case study will focus on
the renewal of the riverbed to increase nursery areas, while another project is
working on building a new fish pass to facilitate the free movement of fish
past migration obstacles.  “For healthy trout populations, rivers need
to be protected and restored, for instance by removing migration hindrances and
improving spawning grounds. We need to increase the efforts for securing
self-sustaining and viable populations of migratory fish in the Baltic Sea”,
said Henri Jokinen, the RETROUT Project manager at HELCOM. In Gdańsk, HELCOM chaired the second day
work group session for the RETROUT work package on ‘Assessment of status and
management of sea trout rivers and stocks.’ This  focuses mainly on the ecological
aspect of trout fishing, notably through assessing fish stock and river habitat
status, and by evaluating river restoration practices to improve trout
populations. The main results will be published as an assessment report and as
a toolbox of best practices for river restoration in the Baltic Sea.  “So far, we have had a very useful workshop
about sea trout assessment and monitoring methods last year, we have collected
a nice data set of past river restoration cases and conducted a valuable amount
of stakeholder interviews to learn about factors of success and failure in
river restoration projects, and we advanced with the river restoration
demonstration projects carried out in the project countries, to mention some of
the achievements. We are in a good place to start on the next half of the
project,” said Jokinen. The HELCOM-led work in RETROUT is in line
with the  on salmon and
sea trout, and supports the  ‘Conservation of
Baltic Salmon (Salmo salar) and Sea Trout (Salmo trutta)
populations by the restoration of their river habitats and management of river
fisheries’. In essence, the RETROUT project aims to
stimulate sustainable economic and social development based on healthy
ecosystems, reflecting the general HELCOM priorities.With 14 partners from Sweden, Estonia,
Latvia, Lithuania and Poland, and including HELCOM, RETROUT is a three-year Interreg
project running until September 2020. RETROUT is a flagship project of the EU
Strategy for the Baltic Sea Region . It is co-financed by the  under the Natural resources
priority field. –For
more information:Henri
RETROUT Project manager 

The RETROUT project had its mid-term meeting in Gdańsk, Poland from 8 to 9 May 2019, looking at achievements so far and the next steps to be taken.

HELCOM expert interview: Jannica Haldin on biodiversity

What is biodiversity?

Biodiversity refers to the variety and variability of all life on Earth, and, contrary to common perception, it is a measure of variation at both the genetic, species, community and ecosystem level. Thus, it doesn’t only deal with species. It refers to anything alive on the planet. And it can be scaled up or down as needed, for instance, “biodiversity of the Baltic Sea”, or “biodiversity of the Gulf of Gdansk”. 

To simplify, you can think of biodiversity as building blocks. Each individual gene, each individual species, each community of species is a building block. The more different building blocks you have, the more different things you can build. And the bigger you build, the more difficult it will be to get knocked down. This also applies to the Baltic Sea, where the building blocks of biodiversity create and maintain the ecosystem.

What is the current state of biodiversity in the Baltic Sea?

The Baltic Sea is unique, there is no other sea like it in the world. This is true for its biodiversity as well. Thousands of species and millions of genes create its distinctive underwater biodiversity. This might sound like a lot, but in reality, these are only a few building blocks compared to most other areas around the world. Due to its relatively low biodiversity, the Baltic Sea is very vulnerable. 

We believe that the Baltic Sea contains around 5000 species, out of which over 2700 are macro species – species you can see with the naked eye. The majority of these species, a total of 1898, belong to the benthic invertebrate group. These are species of animals living around, on or in the bottom of the sea, such as mussels, worms and crustaceans. Of the remaining 832 species, the “plants” of the sea (multicellular algae, vascular plants and bryophytes), make up a substantial proportion, followed by the fish and lamprey group. 

Species diversity is rather low in the Baltic Sea compared to many other marine environments, as the low-salinity, brackish water environment is physiologically demanding to most organisms. 

A clear trend in biodiversity is evident for all groups, with the number of species in an area decreasing along a south to north gradient. This trend is natural and a result of the Baltics unique salinity gradient and high variability in habitat type. These two aspects area also what gives the Baltic Sea a greater biodiversity and variety of plant and animal life than might be expected under more classic conditions.

The brackish water imposes physiological stress on both marine and freshwater organisms, but there are also several examples of genetic adaptation and diversification. Most of the marine species that are present in the Baltic Sea originate from a time when the sea was saltier, and since then only had limited genetic exchange with their counterparts in fully marine waters. On a Baltic-wide scale, marine species live side by side with freshwater species. 

However, the species that have adapted to the Baltic Sea conditions often appear in great abundance. In other words, we have relatively few different species, but the Baltic Sea is quite crowded. 

As many of the species in the Baltic Sea live on the edge of their tolerance to habitat variations, any change to their living environment can lead to radical fluctuations of their abundance. The structure of biodiversity in the Baltic Sea can change significantly with even the smallest modification in environmental conditions. 

Although marine species are generally more common in the southern parts, and freshwater species dominate in the inner and less saline areas, the two groups of species create a unique food web where marine and freshwater species coexist and interact. Because the sea in its current form is quite young, the Baltic Sea still offers several ecological niches available for immigration.

This second HELCOM holistic assessment shows that most fish, birds and marine mammals, as well as benthic and pelagic habitats of the Baltic Sea are not in a healthy state. A deteriorated status is seen in different parts of the system, comprising species which live in the open water column, in coastal areas, as well as those close to the sea floor. The impact is likely to influence the ecosystem’s functioning, the resilience of the system against further environmental changes, and the services the ecosystem provides.

What are the greatest threats and pressures on Baltic Sea biodiversity?

We put pressure on the biodiversity of the Baltic Sea through our actions. Using the building block analogy: everything we do – the pressures we exert – pushes the building blocks further out of place. Depending on the pressure, the blocks get pushed a little or a lot, and it can be only a few blocks or all of them at once. Push too hard and the structure starts to topple. 

Natural systems are complex, and each building block is connected to hundreds of others. We therefore can’t always be sure what impacts we are causing through our activities. But we do know that the more things we do at the same time, the more pressure we put on the system, pushing simultaneously from different sides. And we also know that, like a tower of building blocks, once the first blocks start falling, they can take other blocks with them in their fall. When we start losing genes or species, there is a risk of a domino effect for other species and biodiversity elements.

In order to ensure that the entire system doesn’t collapse, that we don’t lose biodiversity, and that we keep the ecosystem functioning, we need to limit the amount and intensity of the pressure that we cause through our actions. This is done through better managing human activities.

For improving the management of our activities, we need to know which are the ones causing the most pressure, and which can be considered the greatest threat. These need to be targeted first. This is more complex than it seems: Getting the answer right is vital to ensure that we cause the least damage through our activities, and that our conservation efforts yield maximum results.

Due to the comparatively large amount of data that we have on pressures in the Baltic Sea, such as through the Baltic Sea Pressure Index, we have a fairly good idea of what the main pressures in the Baltic Sea are, where they occur, if they are widespread or local, etc. 

Theoretically, the more widespread and the stronger a pressure is, the worse it is from a biodiversity perspective. Major pressures on the Baltic Sea – eutrophication, hazardous substances, introduction of non-indigenous species, and effects of commercial fishing – are all at higher than sustainable levels. 

To understand which human pressures have the greatest impact on biodiversity, we need to know where the pressures and the biodiversity intersect, and how they interact. Unfortunately, we have far less information about these interactions than on the pressures themselves. 

While we are used to looking at the pressures individually, when it comes to the actual effect they have on the living environment – us humans included – we need to understand how pressures act and affect a biodiversity component together. This is what we refer to as cumulative impacts. HELCOM has been working on a cumulative impacts index to get a better idea of this. Each gene, species or community in the Baltic Sea is affected by several pressures at once. Sometimes, the effects of the combined pressures add up to more than the sum of the parts. 

When talking about threats, this might be viewed differently. There can be very strong, and even widespread pressures, that in reality are less of a threat because they are direct. This means that we know their source, and that we know what to do to fix them. So, although the need for action is acute, the long-term threat to biodiversity can be considered less significant –  provided we do something about it now.

On the other end of the spectrum, we have diffuse – or indirect – pressures. These are pressures for which the source is either not known, difficult to manage, or we might not yet know how to manage them. A good example for this is climate change: In the long term, it might be a much bigger threat because we don’t know how to fix it.

What about the HELCOM indicators on biodiversity? What is their use? 

HELCOM uses core indicators as a way of measuring how the sea is doing. It’s like a fever thermometer. Scientist have come together to agree on a threshold, above which we think that biodiversity is doing ok, and below which it shows that something is wrong. We can use these to “take the temperature” of a given biodiversity component and get an idea of what the current state is as well as see if the sea is getting healthier or not, or if we are getting closer to the threshold.

HELCOM biodiversity core indicators currently look at the status of the Baltic Sea as reflected by marine mammals, seabirds, fish, benthic biotopes and pelagic plankton communities. 

What are the trends in regards to biodiversity in the Baltic Sea? 

So what trends are we seeing for biodiversity? Unfortunately, it is not so positive. For the biodiversity core indicators there are cases of inadequate status in all levels of the food web; only a few core indicators have acceptable levels in part of the Baltic Sea, and none of them in all assessed areas. The overall results suggest that the environmental impact on species in the Baltic Sea are far-reaching and not restricted to certain geographic areas or certain parts of the food web. 

However, we should also recall what the state the Baltic Sea environment could have looked like without the work that has been done so far. We know that pressures such as inputs of nutrients and several hazardous substances are decreasing, and that several former pollution hot spots have been removed.

Many pressures have been acting on the Baltic Sea for a long time. Legacies such as nutrients and contaminants will still show unacceptable levels in the marine environment long after their inputs have ceased. Ecosystem models show that responses to nutrient reductions act on the time scale of decades.

So, recovery might take time. But if we limit the amount of pressure we put on the environment it is anticipated that biodiversity will show signs of improvement in the coming years. For this, continued efforts to improve the environmental status of biodiversity are of key importance.

Baltic Sea and ecosystem services as a life-support system in the region: how important is it? 

Let’s get back to the idea of biodiversity as building blocks. Now imagine that every structure you build with your blocks has a function: one cleans the air, one cleans the water, one makes food, etc. This is of course simplified but it is illustrative.

If you only have a few blocks, you can only build one copy of each of the structures, so if one of them is knocked down, for instance the air one, you won’t be able to breathe anymore.

But the more copies you have, the less likely it is that if something gets knocked down, you will lose that function. This is why high biodiversity is considered important. Each unit and each level of biodiversity fulfils a multitude of functions we need to survive, and the more complex the system, the more difficult it is to topple it.

These functions are called ecosystem services and are a natural effect of all the interactions going on in an ecosystem and its biodiversity. Ecosystem services are defined as “the benefits people derive from ecosystems”. Besides provisioning services or goods like food and raw materials, plants, animals, fungi and micro-organisms provide essential regulating services such as pollination of crops, prevention of soil erosion and water purification, and a vast array of cultural services, like recreation and a sense of place.

In spite of the ecological, cultural and economic importance of these services, ecosystems (and the biodiversity that underpins them) are still being degraded and lost as we put more pressures on the ecosystem then it can take. One major reason for this is that the importance of ecosystems to human welfare is still underestimated and not fully recognized or incorporated into every day planning and decision-making.

To what extend does the Baltic Sea’s biodiversity have effects on us humans? 

We humans are part of this world. There is no humans versus the rest of nature, and this is also true for biodiversity. People depend on biodiversity in their daily lives, in ways that are not always obvious or appreciated. If we go back to the idea of toppling the blocks: when a structure crumbles, it affects us as much as all the other parts of the ecosystem. 

The World Health Organisation (WHO) acknowledges that human health ultimately depends on ecosystem products and services, and that these are necessary for good human health and productive livelihoods. Biodiversity loss can have significant direct human health impacts if ecosystem services are no longer adequate to meet social needs. Indirectly, changes in ecosystem services also affect livelihoods, income, local migration, and, in some occasions, may even cause political conflict.

What is HELCOM currently doing on biodiversity? 

HELCOM is the governing body of the Convention on the Protection of the Marine Environment of the Baltic Sea Area. This means that HELCOM works to improve the state of the sea as a whole, which intrinsically means improving the situation for biodiversity. The Helsinki Commission provides a platform for the states around the Baltic Sea and the EU to agree on policies, plans and develop guidelines, recommendations, etc. that the countries can use to manage human activities. 

HELCOM’s vision for the future is a healthy Baltic Sea environment with diverse biological components functioning in balance, resulting in a good ecological status and supporting a wide range of sustainable economic and social activities. 

The HELCOM Contracting Parties have declared their firm determination to assure the ecological restoration of the Baltic Sea, ensuring the possibility of self-regeneration of the marine environment and preservation of its ecological balance. They have agreed that each country individually, as well as where needed jointly, take all appropriate measures to conserve natural habitats and biological diversity and to protect the ecological processes of the Baltic Sea.

This will all be incorporated or maintained in the update of the Baltic Sea Action Plan, which will guide HELCOMs work in the coming years.

HELCOM has a number of Recommendations that deal with biodiversity and conservation, the newest of which was approved as recently as March this year.

HELCOM also works to improve and extend the system of marine protected areas in the Baltic, creating spaces were pressures are limited and biodiversity can be maintained, in the efforts to achieve HELCOMs ultimate aim: to Protect the Marine Environment of the Baltic Sea.