A challenging environment
Marine life is still adapting to conditions in the Baltic, a young sea which first formed as a giant freshwater lake at the end of the last Ice Age, and only became permanently connected to the open seas around 8,000 years ago.
Conditions in the Baltic Sea are naturally challenging for marine species. Winters are harsh, and salinity varies considerably both between different waters and over time. The Baltic Sea is nevertheless home to many species of plants, animals and microorganisms in a great variety of different habitats. A total of 133 distinct marine and coastal habitat types have in fact been classified by HELCOM for conservation purposes, but most of these habitats are threatened by human activity. Major threats to biodiversity include pollution, eutrophication, disturbance and overfishing.
The variety of life
Biodiversity varies around the Baltic due to physical factors, notably depth, the nature of the sea bed, light penetration, oxygen content and especially salinity. The Skagerrak, with a salinity of 30 psu (practical salinity unit, i.e. parts per thousand), is home to some 2,000 marine animal species, including sharks, rays and lobsters. But in the southern waters of the Baltic Proper, where salinity is much lower (10 psu) only around 150 animal species can be found. Ecosystems are generally most productive in coastal waters, where most marine species largely breed, feed and shelter.
Excess nutrients threaten biodiversity
Eutrophication- the presence of excessive nutrients - has caused marked changes in Baltic ecosystems. The water is much less transparent than it was 30-50 years ago, due to the presence of more planktonic algae. This has forced plants that need light for photosynthesis out of deeper waters. Bladder wrack (Fucus vesiculosus) has also become less common along many rocky shorelines, while eel-grass (Zostera marina) - a plant that occupies a crucial ecological niche on sandy sea-beds in the southern and western waters of the Baltic - has also declined.
Special biodiversity features
Birds returning to their old haunts
Preserving biodiversity - HELCOM in action
The 1992 Helsinki Convention was the first regional agreement ever to cover international marine nature conservation over an entire sea. Today, HELCOM HABITAT takes care of nature conservation and integrated coastal zone management issues.
The most threatened habitats and species are dependent on legal protection.
In 1995, 62 marine and coastal areas were designated as Baltic Sea Protected Areas (BSPAs). Millions of seabirds use these areas as staging posts during migration, and more than 30 species breed in them. But very few of the designated areas have been fully incorporated into the system yet, even though many are also otherwise protected in theory. Progress is also needed with the designation of additional offshore areas for enhanced protection.
Take a closer look at the Baltic Sea Protected Areas on our special map!
Marine mammals and birds are suffering from pollution, by-catches, and habitat destruction caused by fishing. HELCOM is working to restrict the use of harmful fishing equipment such as salmon drift nets and bottom-set gill nets. The survival of the Baltic wild salmon (Salmo salar) is threatened by a reduction in its genetic diversity due to artificial breeding.
A special HELCOM sturgeon project has been set up to prevent the extinction of the Baltic variety of the sturgeon in the wild.
Chairman of HELCOM HABITAT
P.O. Box 94
Tel: +358 20 5644457
Fax: +358 20 5644350
Mr. Juha-Markku Leppänen
Tel: +358 9 6220 2227
As shipping has increased during the last twenty years, more and more alien species have been arriving in the Baltic Sea as stowaways. Other non-native species have also been intentionally introduced. Inland waterways eventually connected to the Black Sea and the Caspian Sea have helped still more exotic invaders to find there way to the Baltic. Once alien species establish a foothold, they can spread into through the to other regions of the Baltic at speeds of up to 480 kilometres a year.
Non-native species can seriously disrupt ecosystems, and harm livelihoods. Fishermen in the Gulf of Riga and the Gulf of Finland remember the sudden arrival in 1992 of an alien water flea species. These tiny animals soon started to clog up the gills of fish and fishing nets, leading to serious economic losses. By 1998 the species had spread as far as Stockholm and Gotland.
To help prevent the spread of alien species HELCOM is also supporting a proposed International Convention for the Control and Management of Ships' Ballast Water and Sediments.
Marine alien species of Estonia
Birds returning to their old haunts
The cormorant (Phalacracorax carbo) has recently been making a spectacular comeback around the Baltic, after being almost hunted into extinction earliy in the 20th Century. During the 1990s, a southwestern population stabilized at around 50,000 breeding pairs, and another population has rapidly been expanding eastwards, with Finland's first breeding pair reported in 1996. Conservationists argue that cormorants mainly feed on fish of minor economic value, but since they also raid fishing nets and fish farms, an international management plan prepared under the Bonn Convention has advocated controlled culls to limit cormorant populations.
The white-tailed sea eagle (Haliaeetus albicilla) is also recovering around the Baltic, with its population almost doubling between 1991 and 1998, and its range expanding again into countries like Lithuania and Denmark where eagles have not bred for decades. But the white-tailed sea eagle still needs protection, since as a predator at the top of the food chain, it is highly susceptible pollution.
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