• It took decades for the Baltic Sea’s ecosystem to reach its current degraded state and recovery will not happen quickly
• One of the most important steps to protect the Baltic Sea is reducing nutrient inputs from land that fuel eutrophication
• World Wide Fund for Nature (WWF): Overfishing continues to reduce populations of many fish species in the Baltic ecosystem, the European eel is on the brink of extinction, and only around 500 harbor porpoises remain

ANKARA

Marine life in the Baltic Sea has come under growing threat in recent years due to the increasing effects of global warming, human waste, and the sea’s unique geographical conditions.

Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany, and Denmark — all countries bordering the Baltic Sea — are working, largely in cooperation with the EU, to take measures against these threats.

The Baltic Marine Environment Protection Commission (HELCOM) continues to implement the Baltic Sea Action Plan, which has been in place for five years and aims to protect fish, birds, mammals, and specific habitats.

Anadolu's ongoing "Baltic Sea" file examines the threats facing the natural life in the Baltic Sea and the policies adopted by coastal states.

Eutrophication

One of the biggest problems confronting the Baltic Sea ecosystem is eutrophication.

Eutrophication is the excessive enrichment of water with nutrients — particularly nitrogen and phosphorus — from land-based sources such as agriculture, sewage, and industrial discharges. This leads to massive growth of algae, especially phytoplankton.

These algal blooms block sunlight from reaching underwater plants and seagrasses, while the decomposition of dying algae consumes large amounts of oxygen in deeper waters, creating dead zones where fish, shellfish, and most marine organisms cannot survive.

While the Baltic Sea is almost entirely landlocked and its outlet shallow and its waters remarkably fresh, its salinity is showing a decreasing trend. It is predicted that oxygen deficiency in the ecosystem will increase and the water will become more acidic.

Speaking to Anadolu, Anna Klemela, a researcher from the Finland-based Baltic Sea Action Group (BSAG) civil society organizatiobn, said that one of the most important steps to take to protect the Baltic Sea is to reduce nutrient inputs from land that fuel eutrophication.

She noted that the majority of these nutrients originate from agriculture and forestry.

Measures for the Baltic Sea include limiting sewage discharges into the sea, as well as addressing the use of artificial fertilizers to increase soil productivity, which are washed into the sea via groundwater, exacerbating the eutrophication problem.

In this context, HELCOM promotes practices such as efficient fertilizer management and sustainable agriculture.

Human activities also negatively impact the Baltic ecosystem

Human activities such as overfishing and poor waste management also pose major threats to natural life in the Baltic Sea.

Overfishing has led to a sharp decline in cod populations, along with a noticeable reduction in the size of fish, often by about 20 centimeters.

Germany's GEOMAR Helmholtz Centre for Ocean Research points out that intensive fishing has caused lasting genetic changes in cod DNA, while also driving a steep drop in their numbers.

According to the World Wide Fund for Nature (WWF), overfishing continues to reduce the populations of many fish species in the Baltic ecosystem, the European eel is on the brink of extinction, and only around 500 harbor porpoises remain.

The future of the Baltic Sea

Long-term monitoring and modeling studies by organizations such as HELCOM and BSAG indicate that the state of the Baltic Sea would be significantly worse today without the nutrient reduction measures implemented since the 1980s.

Despite these efforts, underwater biodiversity in the Baltic Sea continues to decline.

Combined with the ongoing effects of eutrophication and accelerating climate change — which further intensifies risks such as oxygen depletion, habitat shifts, and species loss — this spells bad news for many of the sea's unique species.

The ecosystem has reached its current degraded state over several decades, and experts warn that full recovery will take considerable time.

Under EU-HELCOM cooperation and the Baltic Sea Action Plan updated in 2021 — targeting implementation of actions by 2030 at the latest — the nine coastal countries continue joint efforts to reduce nutrient loads, improve water quality, protect biodiversity, and strengthen ecosystem resilience through binding commitments and regular monitoring.

The EU is also providing direct financial support for the removal and management of unexploded ordnance, chemical leaks, and shipwrecks dating back to World War II on the Baltic seabed, as these continue to pose serious risks to marine life and critical underwater infrastructure such as cables and energy lines.

The 2022 Nord Stream pipeline explosions have heightened concerns over the vulnerability of subsea energy infrastructure, prompting further EU scrutiny and investment in seabed security and environmental remediation efforts.