BS11 Threatened marine species

This is an impact (I) indicator. DPSIR = drivers, pressures, state, impact, responses. Moderate negative trend in the 20th century before 1990 (frame). A weak negative trend has continued since 1990 (arrow).

>> Background information

Status

According to the Red List of Finnish Species published in 2010, the Baltic Sea is a primary habitat for 0.8% of all threatened species of Finland. The reason behind this small number is the low total number of species in the Baltic Sea. The brackish water conditions of the Baltic Sea are difficult for both marine and fresh water species. The proportion of marine species of all well known species in Finland is approximately one percent, the same as the proportion of threatened species mentioned above.

Most of the total 17 threatened Baltic Sea species are birds (5), fish (4) and algae (3). The rest of the species are vascular plants, caddisflies and beetles.

There is a large number of unknown species in the Baltic Sea, which conservation status has been impossible to assess due to lack of data. These include the species-rich group of micro algae as well as such groups as red algae and shellfish. Baltic Sea provides a secondary habitat for many threatened fresh water species.

Development

The recent changes in species' red-list classes do not imply for better or worse status of the Baltic Sea. Between years 2000 and 2010 there have been five positive and seven negative changes in conservation status of species.

Of the birds, the declining trend of the Black-Headed Gull population has ended and parly reversed. Also the rare Caspian Tern has become slightly more common. Similar positive development applies also to Vimba Bream, Black Guillemon and Grey Seal, which status was changed from Near Threatened to Least Concern.

The biggest negative change in conservation status concerned the seaspawning Grayling population, which was now assessed as Critically Endangered. Its former conservation status was Near Threatened. Also the status of Greater Scoup is of concern. It changed from Vulnerable to Endangered.

The Shelduck, nesting in open flood meadows and sandy beaches has commonly decreased. The status of the species changed from Near Threatened to Vulnerable. The other species whose status have weakened include Widgeongrass, Velvet Scoter, Common Eider and a water beetle species laccobius decorus. Also their status changed from Near Threatened to Vulnerable.

Threats
The threatened species of the Baltic Sea are at risk of wide range of factors from eutrophication and overgrowth of seashores to hunting, fishing and random factors. Eutrophication and overgrowth are the primary reasons for all vascular plants and Stoneworts. Moreover, as the species' distribution area is very limited, also small-scale changes may be critical.

Threatened fish, such as European Eel and Spined Loach, are threatened by changes in the chemical water quality, especially eutrophication. Spined Loach, that is found only in few sand and clay shores in the Eastern part of the Gulf of Finland, is threatened by hydraulic construction, as well as Grayling that spawns in the coasts of outer islands of the Bothnian Bay. Climate change is assessed to further weaken the status of Grayling and seaspawning Lesser Sparsely-rakered Whitefish.

Disturbance and construction threatens nesting and the nesting sites of Little Tern and White-Tailed Eagle. The primary reason for the vulnerability of the White-Tailed Eagle are chemical disturbances. However, environmental toxins do not harm its nesting as much as in previous decades.

The main reason for of the endangered status of the Greater Scaup is hunting, but also eutrophication of the Baltic Sea poses a threat to it. The Common Guillemot, which nests only on very few outer islets, is threatened by random factors related to contamination of the sea and diseases.
This indicator will be completely updated as the new list of threatened species is completed in 2020. Small revisions and additions may be done before that.

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Updated (14.05.2013)